OPENSSL(1)

NAME
openssl - OpenSSL command line tool

SYNOPSIS
openssl command [command_opt ...] [command_arg ...]

openssl list-standard-commands | list-message-digest-commands | list-cipher-commands | list-cipher-algorithms | list-message-digest-algorithms | list-public-key-algorithms

openssl no-command

DESCRIPTION
OpenSSL is a cryptography toolkit implementing the Transport Layer Security (TLS v1) network protocol, as well as related cryptography standards.

The openssl program is a command line tool for using the various cryptography functions of openssl's crypto library from the shell.

The pseudo-commands list-standard-commands, list-message-digest-commands, and list-cipher-commands output a list (one entry per line) of the names of all standard commands, message digest commands, or cipher commands, respectively, that are available in the present openssl utility.

The pseudo-commands list-cipher-algorithms and list-message-digest-algorithms list all cipher and message digest names, one entry per line. Aliases are listed as:

    from => to

The pseudo-command list-public-key-algorithms lists all supported public key algorithms.

The pseudo-command no-command tests whether a command of the specified name is available. If command does not exist, it returns 0 and prints no-command; otherwise it returns 1 and prints command. In both cases, the output goes to stdout and nothing is printed to stderr. Additional command line arguments are always ignored. Since for each cipher there is a command of the same name, this provides an easy way for shell scripts to test for the availability of ciphers in the openssl program.

Note: no-command is not able to detect pseudo-commands such as quit, list-...-commands, or no-command itself.

ASN1PARSE

openssl asn1parse
    [-i] [-dlimit number] [-dump] [-genconf file] [-genstr str] [-in file] [-inform der | pem | txt] [-length number] [-noout] [-offset number] [-oid file] [-out file] [-strparse offset]

The asn1parse command is a diagnostic utility that can parse ASN.1 structures. It can also be used to extract data from ASN.1 formatted data.

The options are as follows:

-dlimit number
    Dump the first number bytes of unknown data in hex form.

-dump
    Dump unknown data in hex form.

-genconf file, -genstr str
    Generate encoded data based on string str, file file, or both, using the format described in ASN1_generate_nconf(3). If only file is present then the string is obtained from the default section using the name “asn1”. The encoded data is passed through the ASN.1 parser and printed out as though it came from a file; the contents can thus be examined and written to a file using the -out option.

-i  Indent the output according to the "depth" of the structures.

-in file
    The input file to read from, or standard input if not specified.

-inform der | pem | txt
    The input format.

-length number
    Number of bytes to parse; the default is until end of file.

-noout
    Do not output the parsed version of the input file.

-offset number
    Starting offset to begin parsing; the default is start of file.

-oid file
    A file containing additional object identifiers (OIDs). If an OID (object identifier) is not part of openssl's internal table, it will be represented in numerical form (for example 1.2.3.4).

    Each line consists of three columns: the first column is the OID in numerical format and should be followed by whitespace. The second column is the "short name", which is a single word followed by whitespace. The final column is the rest of the line and is the "long name". asn1parse displays the long name.

-out file
    The DER-encoded output file; the default is no encoded output (useful when combined with -strparse).

-strparse offset
    Parse the content octets of the ASN.1 object starting at offset. This option can be used multiple times to "drill down" into a nested structure.

CA

openssl ca
    [-batch] [-cert file] [-config file] [-create_serial] [-crl_CA_compromise time] [-crl_compromise time] [-crl_hold instruction] [-crl_reason reason] [-crldays days] [-crlexts section] [-crlhours hours] [-crlsec seconds] [-days arg] [-enddate date] [-extensions section] [-extfile file] [-gencrl] [-in file] [-infiles] [-key password] [-keyfile file] [-keyform pem | der] [-md alg] [-msie_hack] [-multivalue-rdn] [-name section] [-noemailDN] [-notext] [-out file] [-outdir directory] [-passin arg] [-policy arg] [-preserveDN] [-revoke file] [-selfsign] [-sigopt nm:v] [-spkac file] [-ss_cert file] [-startdate date] [-status serial] [-subj arg] [-updatedb] [-utf8] [-verbose]

The ca command is a minimal certificate authority (CA) application. It can be used to sign certificate requests in a variety of forms and generate certificate revocation lists (CRLs). It also maintains a text database of issued certificates and their status.

The options relevant to CAs are as follows:

-batch
    Batch mode. In this mode no questions will be asked and all certificates will be certified automatically.

-cert file
    The CA certificate file.

-config file
    Specify an alternative configuration file.

-create_serial
    If reading the serial from the text file as specified in the configuration fails, create a new random serial to be used as the next serial number.

-days arg
    The number of days to certify the certificate for.

-enddate date
    Set the expiry date. The format of the date is [YY]YYMMDDHHMMSSZ, with all four year digits required for dates from 2050 onwards.

-extensions section
    The section of the configuration file containing certificate extensions to be added when a certificate is issued (defaults to x509_extensions unless the -extfile option is used). If no extension section is present, a V1 certificate is created. If the extension section is present (even if it is empty), then a V3 certificate is created. See the x509v3.cnf(5) manual page for details of the extension section format.

-extfile file
    An additional configuration file to read certificate extensions from (using the default section unless the -extensions option is also used).

-in file
    An input file containing a single certificate request to be signed by the CA.

-infiles
    If present, this should be the last option; all subsequent arguments are assumed to be the names of files containing certificate requests.

-key password
    The password used to encrypt the private key. Since on some systems the command line arguments are visible, this option should be used with caution.

-keyfile file
    The private key to sign requests with.

-keyform pem | der
    Private key file format. The default is pem.

-md alg
    The message digest to use. Possible values include md5 and sha1. This option also applies to CRLs.

-msie_hack
    This is a legacy option to make ca work with very old versions of the IE certificate enrollment control "certenr3". It used UniversalStrings for almost everything. Since the old control has various security bugs, its use is strongly discouraged. The newer control "Xenroll" does not need this option.

-multivalue-rdn
    This option causes the -subj argument to be interpreted with full support for multivalued RDNs, for example "/DC=org/DC=OpenSSL/DC=users/UID=123456+CN=John Doe". If -multivalue-rdn is not used, the UID value is set to "123456+CN=John Doe".

-name section
    Specifies the configuration file section to use (overrides default_ca in the ca section).

-noemailDN
    The DN of a certificate can contain the EMAIL field if present in the request DN, however it is good policy just having the email set into the altName extension of the certificate. When this option is set, the EMAIL field is removed from the certificate's subject and set only in the, eventually present, extensions. The email_in_dn keyword can be used in the configuration file to enable this behaviour.

-notext
    Don't output the text form of a certificate to the output file.

-out file
    The output file to output certificates to. The default is standard output. The certificate details will also be printed out to this file in PEM format, except that -spkac outputs DER format.

-outdir directory
    The directory to output certificates to. The certificate will be written to a file consisting of the serial number in hex with ".pem" appended.

-passin arg
    The key password source.

-policy arg
    Define the CA "policy" to use. The policy section in the configuration file consists of a set of variables corresponding to certificate DN fields. The values may be one of "match" (the value must match the same field in the CA certificate), "supplied" (the value must be present), or "optional" (the value may be present). Any fields not mentioned in the policy section are silently deleted, unless the -preserveDN option is set, but this can be regarded more of a quirk than intended behaviour.

-preserveDN
    Normally, the DN order of a certificate is the same as the order of the fields in the relevant policy section. When this option is set, the order is the same as the request. This is largely for compatibility with the older IE enrollment control which would only accept certificates if their DNs matched the order of the request. This is not needed for Xenroll.

-selfsign
    Indicates the issued certificates are to be signed with the key the certificate requests were signed with, given with -keyfile. Certificate requests signed with a different key are ignored. If -gencrl, -spkac, or -ss_cert are given, -selfsign is ignored.

    A consequence of using -selfsign is that the self-signed certificate appears among the entries in the certificate database (see the configuration option database) and uses the same serial number counter as all other certificates signed with the self-signed certificate.

-sigopt nm:v
    Pass options to the signature algorithm during sign or certify operations. The names and values of these options are algorithm-specific.

-spkac file
    A file containing a single Netscape signed public key and challenge, and additional field values to be signed by the CA. This will usually come from the KEYGEN tag in an HTML form to create a new private key. It is, however, possible to create SPKACs using the spkac utility.

    The file should contain the variable SPKAC set to the value of the SPKAC and also the required DN components as name value pairs. If it's necessary to include the same component twice, then it can be preceded by a number and a ‘’..

-ss_cert file
    A single self-signed certificate to be signed by the CA.

-startdate date
    Set the start date. The format of the date is [YY]YYMMDDHHMMSSZ, with all four year digits required for dates from 2050 onwards.

-subj arg
    Supersedes the subject name given in the request. The arg must be formatted as /type0=value0/type1=value1/ type2=...; characters may be escaped by ‘\’ (backslash), no spaces are skipped.

-utf8
    Interpret field values read from a terminal or obtained from a configuration file as UTF-8 strings. By default, they are interpreted as ASCII.

-verbose
    Print extra details about the operations being performed.

The options relevant to CRLs are as follows:

-crl_CA_compromise time
    This is the same as -crl_compromise, except the revocation reason is set to CACompromise.

-crl_compromise time
    Set the revocation reason to keyCompromise and the compromise time to time. time should be in GeneralizedTime format, i.e. YYYYMMDDHHMMSSZ.

-crl_hold instruction
    Set the CRL revocation reason code to certificateHold and the hold instruction to instruction which must be an OID. Although any OID can be used, only holdInstructionNone (the use of which is discouraged by RFC 2459), holdInstructionCallIssuer or holdInstructionReject will normally be used.

-crl_reason reason
    Revocation reason, where reason is one of: unspecified, keyCompromise, CACompromise, affiliationChanged, superseded, cessationOfOperation, certificateHold or removeFromCRL. The matching of reason is case insensitive. Setting any revocation reason will make the CRL v2. In practice, removeFromCRL is not particularly useful because it is only used in delta CRLs which are not currently implemented.

-crldays days
    The number of days before the next CRL is due. This is the days from now to place in the CRL nextUpdate field.

-crlexts section
    The section of the configuration file containing CRL extensions to include. If no CRL extension section is present then a V1 CRL is created; if the CRL extension section is present (even if it is empty) then a V2 CRL is created. The CRL extensions specified are CRL extensions and not CRL entry extensions. It should be noted that some software can't handle V2 CRLs. See the x509v3.cnf(5) manual page for details of the extension section format.

-crlhours hours
    The number of hours before the next CRL is due.

-crlsec seconds
    The number of seconds before the next CRL is due.

-gencrl
    Generate a CRL based on information in the index file.

-revoke file
    A file containing a certificate to revoke.

-status serial
    Show the status of the certificate with serial number serial.

-updatedb
    Update the database index to purge expired certificates.

Many of the options can be set in the ca section of the configuration file (or in the default section of the configuration file), specified using default_ca or -name. The options preserve and msie_hack are read directly from the ca section.

Many of the configuration file options are identical to command line options. Where the option is present in the configuration file and the command line, the command line value is used. Where an option is described as mandatory, then it must be present in the configuration file or the command line equivalent (if any) used.

certificate
    The same as -cert. It gives the file containing the CA certificate. Mandatory.

copy_extensions
    Determines how extensions in certificate requests should be handled. If set to none or this option is not present, then extensions are ignored and not copied to the certificate. If set to copy, then any extensions present in the request that are not already present are copied to the certificate. If set to copyall, then all extensions in the request are copied to the certificate: if the extension is already present in the certificate it is deleted first.

    The copy_extensions option should be used with caution. If care is not taken, it can be a security risk. For example, if a certificate request contains a basicConstraints extension with CA:TRUE and the copy_extensions value is set to copyall and the user does not spot this when the certificate is displayed, then this will hand the requester a valid CA certificate.

    This situation can be avoided by setting copy_extensions to copy and including basicConstraints with CA:FALSE in the configuration file. Then if the request contains a basicConstraints extension, it will be ignored.

    The main use of this option is to allow a certificate request to supply values for certain extensions such as subjectAltName.

crl_extensions
    The same as -crlexts.

crlnumber
    A text file containing the next CRL number to use in hex. The CRL number will be inserted in the CRLs only if this file exists. If this file is present, it must contain a valid CRL number.

database
    The text database file to use. Mandatory. This file must be present, though initially it will be empty.

default_crl_hours, default_crl_days
    The same as the -crlhours and -crldays options. These will only be used if neither command line option is present. At least one of these must be present to generate a CRL.

default_days
    The same as the -days option. The number of days to certify a certificate for.

default_enddate
    The same as the -enddate option. Either this option or default_days (or the command line equivalents) must be present.

default_md
    The same as the -md option. The message digest to use. Mandatory.

default_startdate
    The same as the -startdate option. The start date to certify a certificate for. If not set, the current time is used.

email_in_dn
    The same as -noemailDN. If the EMAIL field is to be removed from the DN of the certificate, simply set this to "no". If not present, the default is to allow for the EMAIL field in the certificate's DN.

msie_hack
    The same as -msie_hack.

name_opt, cert_opt
    These options allow the format used to display the certificate details when asking the user to confirm signing. All the options supported by the x509 utilities' -nameopt and -certopt switches can be used here, except that no_signame and no_sigdump are permanently set and cannot be disabled (this is because the certificate signature cannot be displayed because the certificate has not been signed at this point).

    For convenience, the value ca_default is accepted by both to produce a reasonable output.

    If neither option is present, the format used in earlier versions of openssl is used. Use of the old format is strongly discouraged because it only displays fields mentioned in the policy section, mishandles multicharacter string types and does not display extensions.

new_certs_dir
    The same as the -outdir command line option. It specifies the directory where new certificates will be placed. Mandatory.

oid_file
    This specifies a file containing additional object identifiers. Each line of the file should consist of the numerical form of the object identifier followed by whitespace, then the short name followed by whitespace and finally the long name.

oid_section
    This specifies a section in the configuration file containing extra object identifiers. Each line should consist of the short name of the object identifier followed by ‘=’ and the numerical form. The short and long names are the same when this option is used.

policy
    The same as -policy. Mandatory.

preserve
    The same as -preserveDN.

private_key
    Same as the -keyfile option. The file containing the CA private key. Mandatory.

serial
    A text file containing the next serial number to use in hex. Mandatory. This file must be present and contain a valid serial number.

unique_subject
    If the value yes is given, the valid certificate entries in the database must have unique subjects. If the value no is given, several valid certificate entries may have the exact same subject. The default value is yes.

    Note that it is valid in some circumstances for certificates to be created without any subject. In cases where there are multiple certificates without subjects this does not count as a duplicate.

x509_extensions
    The same as -extensions.

CERTHASH

openssl certhash
    [-nv] dir ...

The certhash command calculates a hash value of ".pem" file in the specified directory list and creates symbolic links for each file, where the name of the link is the hash value. See the SSL_CTX_load_verify_locations(3) manual page for how hash links are used.

The links created are of the form "HHHHHHHH.D", where each ‘H’ is a hexadecimal character and ‘D’ is a single decimal digit. The hashes for CRLs look similar, except the letter ‘r’ appears after the period, like this: "HHHHHHHH.rD". When processing a directory, certhash will first remove all links that have a name in that syntax and invalid reference.

Multiple objects may have the same hash; they will be indicated by incrementing the ‘D’ value. Duplicates are found by comparing the full SHA256 fingerprint. A warning will be displayed if a duplicate is found.

A warning will also be displayed if there are files that cannot be parsed as either a certificate or a CRL.

The options are as follows:

-n  Perform a dry-run, and do not make any changes.

-v  Print extra details about the processing.

dir ...
    Specify the directories to process.

CIPHERS
openssl ciphers [-hsVv] [-tls1_2] [-tls1_3] [control]

The ciphers command converts the control string from the format documented in SSL_CTX_set_cipher_list(3) into an ordered SSL cipher suite preference list. If no control string is specified, the DEFAULT list is printed.

The options are as follows:

-h,?
    Print a brief usage message.

-s  Only list ciphers that are supported by the TLS method.

-tls1_2 | -tls1_3
    In combination with the -s option, list the ciphers which could be used if the specified protocol version were negotiated.

-V  Verbose. List ciphers with cipher suite code in hex format, cipher name, and a complete description of protocol version, key exchange, authentication, encryption, and mac algorithms.

-v  Like -V, but without cipher suite codes.

CMS

openssl cms
    [ -aes128 | -aes192 | -aes256 | -camellia128 | -camellia192 | -camellia256 | -des | -des3 | -rc2-40 | -rc2-64 | -rc2-128] [-CAfile file] [-CApath directory] [-binary] [-certfile file] [-certsout file] [-cmsout] [-compress] [-content file] [-crlfeol] [-data_create] [-data_out] [-debug_decrypt] [-decrypt] [-digest_create] [-digest_verify] [-econtent_type type] [-encrypt] [-EncryptedData_decrypt] [-EncryptedData_encrypt] [-from addr] [-in file] [-inform der | pem | smime] [-inkey file] [-keyform der | pem] [-keyid] [-keyopt nm:v] [-md digest] [-no_attr_verify] [-no_content_verify] [-no_signer_cert_verify] [-noattr] [-nocerts] [-nodetach] [-nointern] [-nooldmime] [-noout] [-nosigs] [-nosmimecap] [-noverify] [-out file] [-outform der | pem | smime] [-passin src] [-print] [-pwri_password arg] [-rctform der | pem | smime] [-receipt_request_all | -receipt_request_first] [-receipt_request_from addr] [-receipt_request_print] [-receipt_request_to addr] [-recip file] [-resign] [-secretkey key] [-secretkeyid id] [-sign] [-sign_receipt] [-signer file] [-stream | -indef | -noindef] [-subject s] [-text] [-to addr] [-uncompress] [-verify] [-verify_receipt file] [-verify_retcode] [cert.pem ...]

The cms command handles S/MIME v3.1 mail. It can encrypt, decrypt, sign and verify, compress and uncompress S/MIME messages.

The MIME message must be sent without any blank lines between the headers and the output. Some mail programs will automatically add a blank line. Piping the mail directly to sendmail is one way to achieve the correct format.

The supplied message to be signed or encrypted must include the necessary MIME headers or many S/MIME clients won't display it properly (if at all). You can use the -text option to automatically add plain text headers.

A "signed and encrypted" message is one where a signed message is then encrypted. This can be produced by encrypting an already signed message.

There are various operation options that set the type of operation to be performed. The meaning of the other options varies according to the operation type.

-encrypt
    Encrypt mail for the given recipient certificates. Input file is the message to be encrypted. The output file is the encrypted mail in MIME format. The actual CMS type is EnvelopedData. Note that no revocation check is done for the recipient cert, so if that key has been compromised, others may be able to decrypt the text.

-decrypt
    Decrypt mail using the supplied certificate and private key. Expects an encrypted mail message in MIME format for the input file. The decrypted mail is written to the output file.

-sign
    Sign mail using the supplied certificate and private key. Input file is the message to be signed. The signed message in MIME format is written to the output file.

-verify
    Verify signed mail. Expects a signed mail message on input and outputs the signed data. Both clear text and opaque signing are supported.

-cmsout
    Take an input message and write out a PEM encoded CMS structure.

-resign
    Resign a message. Take an existing message and one or more new signers. This operation uses an existing message digest when adding a new signer. This means that attributes must be present in at least one existing signer using the same message digest or this operation will fail.

-data_create
    Create a CMS Data type.

-data_out
    Output a content from the input CMS Data type.

-digest_create
    Create a CMS DigestedData type.

-digest_verify
    Verify a CMS DigestedData type and output the content.

-compress
    Create a CMS CompressedData type. Must be compiled with zlib support for this option to work.

-uncompress
    Uncompress a CMS CompressedData type and output the content. Must be compiled with zlib support for this option to work.

-EncryptedData_encrypt
    Encrypt a content using supplied symmetric key and algorithm using a CMS EncryptedData type.

-EncryptedData_decrypt
    Decrypt a CMS EncryptedData type using supplied symmetric key.

-sign_receipt
    Generate and output a signed receipt for the supplied message. The input message must contain a signed receipt request. Functionality is otherwise similar to the -sign operation.

    -verify_receipt file Verify a signed receipt in file. The input message must contain the original receipt request. Functionality is otherwise similar to the -verify operation.

The remaining options are as follows:

    -aes128 | -aes192 | -aes256 | -camellia128 | -camellia192 | -camellia256 | -des | -des3 | -rc2-40 | -rc2-64 | -rc2-128 The encryption algorithm to use. 128-, 192-, or 256-bit AES, 128-, 192-, or 256-bit CAMELLIA, DES (56 bits), triple DES (168 bits), or 40-, 64-, or 128-bit RC2, respectively; if not specified, triple DES is used. Only used with -encrypt and -EncryptedData_encrypt commands.

-binary
    Normally the input message is converted to "canonical" format which is effectively using CR/LF as end of line, as required by the S/MIME specification. When this option is present, no translation occurs. This is useful when handling binary data which may not be in MIME format.

-CAfile file
    A file containing trusted CA certificates, used with -verify and -verify_receipt.

-CApath directory
    A directory containing trusted CA certificates, used with -verify and -verify_receipt. This directory must be a standard certificate directory: that is a hash of each subject name (using x509 -hash) should be linked to each certificate.

cert.pem ...
    One or more certificates of message recipients: used when encrypting a message.

-certfile file
    Allows additional certificates to be specified. When signing, these will be included with the message. When verifying, these will be searched for the signer's certificates. The certificates should be in PEM format.

-certsout file
    A file that any certificates contained in the message are written to.

    -check_ss_sig, -crl_check, -crl_check_all, -extended_crl, -ignore_critical, -issuer_checks, -policy, -policy_check, -purpose, -x509_strict Set various certificate chain validation options. See the verify command for details.

-content file
    A file containing the detached content. This is only useful with the -verify command. This is only usable if the CMS structure is using the detached signature form where the content is not included. This option will override any content if the input format is S/MIME and it uses the multipart/signed MIME content type.

-crlfeol
    Output a S/MIME message with CR/LF end of line.

-debug_decrypt
    Set the CMS_DEBUG_DECRYPT flag when decrypting. This option should be used with caution, since this can be used to disable the MMA attack protection and return an error if no recipient can be found. See the CMS_decrypt(3) manual page for details of the flag.

    -from addr, -subject s, -to addr The relevant mail headers. These are included outside the signed portion of a message so they may be included manually. If signing then many S/MIME mail clients check the signer's certificate's email address matches that specified in the From: address.

-econtent_type type
    Set the encapsulated content type, used with -sign. If not supplied, the Data type is used. The type argument can be any valid OID name in either text or numerical format.

-in file
    The input message to be encrypted or signed or the message to be decrypted or verified.

-inform der | pem | smime
    The input format for the CMS structure. The default is smime, which reads an S/MIME format message. pem and der format change this to expect PEM and DER format CMS structures instead. This currently only affects the input format of the CMS structure; if no CMS structure is being input (for example with -encrypt or -sign) this option has no effect.

-inkey file
    The private key to use when signing or decrypting. This must match the corresponding certificate. If this option is not specified then the private key must be included in the certificate file specified with the -recip or -signer file. When signing, this option can be used multiple times to specify successive keys.

-keyform der | pem
    Input private key format. The default is pem.

-keyid
    Use subject key identifier to identify certificates instead of issuer name and serial number. The supplied certificate must include a subject key identifier extension. Supported by -sign and -encrypt operations.

-keyopt nm:v
    Set customised parameters for the preceding key or certificate for encryption and signing. It can currently be used to set RSA-PSS for signing, RSA-OAEP for encryption or to modify default parameters for ECDH. This option can be used multiple times.

-md digest
    The digest algorithm to use when signing or resigning. If not present then the default digest algorithm for the signing key will be used (usually SHA1).

-no_attr_verify
    Do not verify the signer's attribute of a signature.

-no_content_verify
    Do not verify the content of a signed message.

-no_signer_cert_verify
    Do not verify the signer's certificate of a signed message.

-noattr
    Do not include attributes. Normally when a message is signed a set of attributes are included which include the signing time and supported symmetric algorithms. With this option they are not included.

-nocerts
    Do not include the signer's certificate. This will reduce the size of the signed message but the verifier must have a copy of the signer's certificate available locally (passed using the -certfile option for example).

-nodetach
    When signing a message, use opaque signing. This form is more resistant to translation by mail relays but it cannot be read by mail agents that do not support S/MIME. Without this option cleartext signing with the MIME type multipart/signed is used.

-nointern
    Only the certificates specified in the -certfile option are used. When verifying a message, normally certificates (if any) included in the message are searched for the signing certificate. The supplied certificates can still be used as untrusted CAs however.

-nooldmime
    Output an old S/MIME content type like "application/x-pkcs7-".

-noout
    Do not output the parsed CMS structure for the -cmsout operation. This is useful when combined with the -print option or if the syntax of the CMS structure is being checked.

-nosigs
    Do not try to verify the signatures on the message.

-nosmimecap
    Exclude the list of supported algorithms from signed attributes; other options such as signing time and content type are still included.

-noverify
    Do not verify the signer's certificate of a signed message.

-out file
    The message text that has been decrypted or verified or the output MIME format message that has been signed or verified.

-outform der | pem | smime
    This specifies the output format for the CMS structure. The default is smime, which writes an S/MIME format message. pem and der format change this to write PEM and DER format CMS structures instead. This currently only affects the output format of the CMS structure; if no CMS structure is being output (for example with -verify or -decrypt) this option has no effect.

-passin src
    The private key password source.

-print
    Print out all fields of the CMS structure for the -cmsout operation. This is mainly useful for testing purposes.

-pwri_password arg
    Specify PasswordRecipientInfo (PWRI) password to use. Supported by the -encrypt and -decrypt operations.

-rctform der | pem | smime
    Specify the format for a signed receipt for use with the -receipt_verify operation. The default is smime.

-receipt_request_all | -receipt_request_first
    Indicate requests should be provided by all recipient or first tier recipients (those mailed directly and not from a mailing list), for the -sign operation to include a signed receipt request. Ignored if -receipt_request_from is included.

-receipt_request_from addr
    Add an explicit email address where receipts should be supplied.

-receipt_request_print
    Print out the contents of any signed receipt requests for the -verify operation.

-receipt_request_to addr
    Add an explicit email address where signed receipts should be sent to. This option must be supplied if a signed receipt is requested.

-recip file
    When decrypting a message, this specifies the recipient's certificate. The certificate must match one of the recipients of the message or an error occurs. When encrypting a message, this option may be used multiple times to specify each recipient. This form must be used if customised parameters are required (for example to specify RSA-OAEP). Only certificates carrying RSA, Diffie-Hellman or EC keys are supported by this option.

-secretkey key
    Specify symmetric key to use. The key must be supplied in hex format and be consistent with the algorithm used. Supported by the -EncryptedData_encrypt, -EncryptedData_decrypt, -encrypt and -decrypt operations. When used with -encrypt or -decrypt, the supplied key is used to wrap or unwrap the content encryption key using an AES key in the KEKRecipientInfo type.

-secretkeyid id
    The key identifier for the supplied symmetric key for KEKRecipientInfo type. This option must be present if the -secretkey option is used with -encrypt. With -decrypt operations the id is used to locate the relevant key; if it is not supplied then an attempt is used to decrypt any KEKRecipientInfo structures.

-signer file
    A signing certificate when signing or resigning a message; this option can be used multiple times if more than one signer is required. If a message is being verified then the signers certificates will be written to this file if the verification was successful.

    -stream | -indef | -noindef The -stream and -indef options are equivalent and enable streaming I/O for encoding operations. This permits single pass processing of data without the need to hold the entire contents in memory, potentially supporting very large files. Streaming is automatically set for S/MIME signing with detached data if the output format is smime; it is currently off by default for all other operations. -noindef disable streaming I/O where it would produce an indefinite length constructed encoding. This option currently has no effect.

-text
    Add plain text (text/plain) MIME headers to the supplied message if encrypting or signing. If decrypting or verifying, it strips off text headers: if the decrypted or verified message is not of MIME type text/plain then an error occurs.

-verify_retcode
    Set verification error code to exit code to indicate what verification error has occurred. Supported by -verify operation only. Exit code value minus 32 shows verification error code. See verify command for the list of verification error code.

The exit codes for cms are as follows:

0   The operation was completely successful.
1   An error occurred parsing the command options.
2   One of the input files could not be read.
3   An error occurred creating the CMS file or when reading the MIME message.
4   An error occurred decrypting or verifying the message.
5   The message was verified correctly but an error occurred writing out the signer's certificates.
6   An error occurred writing the output file.
32+ A verify error occurred while -verify_retcode is specified.

CRL

openssl crl
    [-CAfile file] [-CApath dir] [-crlnumber] [-fingerprint] [-hash] [-hash_old] [-in file] [-inform der | pem] [-issuer] [-lastupdate] [-nameopt option] [-nextupdate] [-noout] [-out file] [-outform der | pem] [-text] [-verify]

The crl command processes CRL files in DER or PEM format.

The options are as follows:

-CAfile file
    Verify the signature on a CRL by looking up the issuing certificate in file.

-CApath directory
    Verify the signature on a CRL by looking up the issuing certificate in dir. This directory must be a standard certificate directory, i.e. a hash of each subject name (using x509 -hash) should be linked to each certificate.

-crlnumber
    Print the CRL number.

-fingerprint
    Print the CRL fingerprint.

-hash
    Output a hash of the issuer name. This can be used to look up CRLs in a directory by issuer name.

-hash_old
    Output an old-style (MD5) hash of the issuer name.

-in file
    The input file to read from, or standard input if not specified.

-inform der | pem
    The input format.

-issuer
    Output the issuer name.

-lastupdate
    Output the thisUpdate field. This option is misnamed for historical reasons.

-nameopt option
    Specify certificate name options.

-nextupdate
    Output the nextUpdate field.

-noout
    Do not output the encoded version of the CRL.

-out file
    The output file to write to, or standard output if not specified.

-outform der | pem
    The output format.

-text
    Print the CRL in plain text.

-verify
    Verify the signature on the CRL.

CRL2PKCS7

openssl crl2pkcs7
    [-certfile file] [-in file] [-inform der | pem] [-nocrl] [-out file] [-outform der | pem]

The crl2pkcs7 command takes an optional CRL and one or more certificates and converts them into a PKCS#7 degenerate "certificates only" structure.

The options are as follows:

-certfile file
    Add the certificates in PEM file to the PKCS#7 structure. This option can be used more than once to read certificates from multiple files.

-in file
    Read the CRL from file, or standard input if not specified.

-inform der | pem
    The input format.

-nocrl
    Normally, a CRL is included in the output file. With this option, no CRL is included in the output file and a CRL is not read from the input file.

-out file
    Write the PKCS#7 structure to file, or standard output if not specified.

-outform der | pem
    The output format.

DGST

openssl dgst
    [-cdr] [-binary] [- digest] [-hex] [-hmac key] [-keyform pem] [-mac algorithm] [-macopt nm:v] [-out file] [-passin arg] [-prverify file] [-sign file] [-signature file] [-sigopt nm:v] [-verify file] [file ...]

The digest functions output the message digest of a supplied file or files in hexadecimal form. They can also be used for digital signing and verification.

The options are as follows:

-binary
    Output the digest or signature in binary form.

-c  Print the digest in two-digit groups separated by colons.

-d  Print BIO debugging information.

- digest
    Use the specified message digest. The default is SHA256. The available digests can be displayed using openssl list-message-digest-commands. The following are equivalent: openssl dgst -sha256 and openssl sha256.

-hex
    Digest is to be output as a hex dump. This is the default case for a "normal" digest as opposed to a digital signature.

-hmac key
    Create a hashed MAC using key.

-keyform pem
    Specifies the key format to sign the digest with.

-mac algorithm
    Create a keyed Message Authentication Code (MAC). The most popular MAC algorithm is HMAC (hash-based MAC), but there are other MAC algorithms which are not based on hash. MAC keys and other options should be set via the -macopt parameter.

-macopt nm:v
    Passes options to the MAC algorithm, specified by -mac. The following options are supported by HMAC:

    key:string
        Specifies the MAC key as an alphanumeric string (use if the key contain printable characters only). String length must conform to any restrictions of the MAC algorithm.

    hexkey:string
        Specifies the MAC key in hexadecimal form (two hex digits per byte). Key length must conform to any restrictions of the MAC algorithm.

-out file
    The output file to write to, or standard output if not specified.

-passin arg
    The key password source.

-prverify file
    Verify the signature using the private key in file. The output is either "Verification OK" or "Verification Failure".

-r  Print the digest in coreutils format.

-sign file
    Digitally sign the digest using the private key in file.

-signature file
    The actual signature to verify.

-sigopt nm:v
    Pass options to the signature algorithm during sign or verify operations. The names and values of these options are algorithm-specific.

-verify file
    Verify the signature using the public key in file. The output is either "Verification OK" or "Verification Failure".

file ...
    File or files to digest. If no files are specified then standard input is used.

DHPARAM

openssl dhparam
    [-2 | -5] [-C] [-check] [-dsaparam] [-in file] [-inform der | pem] [-noout] [-out file] [-outform der | pem] [-text] [numbits]

The dhparam command is used to manipulate DH parameter files. Only the older PKCS#3 DH is supported, not the newer X9.42 DH.

The options are as follows:

-2, -5
    The generator to use; 2 is the default. If present, the input file is ignored and parameters are generated instead.

-C  Convert the parameters into C code. The parameters can then be loaded by calling the get_dhnumbits function.

-check
    Check the DH parameters.

-dsaparam
    Read or create DSA parameters, converted to DH format on output. Otherwise, "strong" primes (such that (p-1)/2 is also prime) will be used for DH parameter generation.

    DH parameter generation with the -dsaparam option is much faster, and the recommended exponent length is shorter, which makes DH key exchange more efficient. Beware that with such DSA-style DH parameters, a fresh DH key should be created for each use to avoid small-subgroup attacks that may be possible otherwise.

-in file
    The input file to read from, or standard input if not specified.

-inform der | pem
    The input format.

-noout
    Do not output the encoded version of the parameters.

-out file
    The output file to write to, or standard output if not specified.

-outform der | pem
    The output format.

-text
    Print the DH parameters in plain text.

numbits
    Generate a parameter set of size numbits. It must be the last option. If not present, a value of 2048 is used. If this value is present, the input file is ignored and parameters are generated instead.

DSA

openssl dsa
    [ -aes128 | -aes192 | -aes256 | -des | -des3] [-in file] [-inform der | pem | pvk] [-modulus] [-noout] [-out file] [-outform der | pem | pvk] [-passin arg] [-passout arg] [-pubin] [-pubout] [-pvk-none | -pvk-strong | -pvk-weak] [-text]

The dsa command processes DSA keys. They can be converted between various forms and their components printed out.

Note: This command uses the traditional SSLeay compatible format for private key encryption: newer applications should use the more secure PKCS#8 format using the pkcs8 command.

The options are as follows:

    -aes128 | -aes192 | -aes256 | -des | -des3 Encrypt the private key with the AES, DES, or the triple DES ciphers, respectively, before outputting it. A pass phrase is prompted for. If none of these options are specified, the key is written in plain text. This means that using the dsa utility to read an encrypted key with no encryption option can be used to remove the pass phrase from a key, or by setting the encryption options it can be used to add or change the pass phrase. These options can only be used with PEM format output files.

-in file
    The input file to read from, or standard input if not specified. If the key is encrypted, a pass phrase will be prompted for.

-inform der | pem | pvk
    The input format.

-modulus
    Print the value of the public key component of the key.

-noout
    Do not output the encoded version of the key.

-out file
    The output file to write to, or standard output if not specified. If any encryption options are set then a pass phrase will be prompted for.

-outform der | pem | pvk
    The output format.

-passin arg
    The key password source.

-passout arg
    The output file password source.

-pubin
    Read in a public key, not a private key.

-pubout
    Output a public key, not a private key. Automatically set if the input is a public key.

    -pvk-none | -pvk-strong | -pvk-weak Enable or disable PVK encoding. The default is -pvk-strong.

-text
    Print the public/private key in plain text.

DSAPARAM

openssl dsaparam
    [-C] [-genkey] [-in file] [-inform der | pem] [-noout] [-out file] [-outform der | pem] [-text] [numbits]

The dsaparam command is used to manipulate or generate DSA parameter files.

The options are as follows:

-C  Convert the parameters into C code. The parameters can then be loaded by calling the get_dsaXXX function.

-genkey
    Generate a DSA key either using the specified or generated parameters.

-in file
    The input file to read from, or standard input if not specified. If the numbits parameter is included, then this option is ignored.

-inform der | pem
    The input format.

-noout
    Do not output the encoded version of the parameters.

-out file
    The output file to write to, or standard output if not specified.

-outform der | pem
    The output format.

-text
    Print the DSA parameters in plain text.

numbits
    Generate a parameter set of size numbits. If this option is included, the input file is ignored.

EC

openssl ec
    [-conv_form arg] [-des] [-des3] [-in file] [-inform der | pem] [-noout] [-out file] [-outform der | pem] [-param_enc arg] [-param_out] [-passin arg] [-passout arg] [-pubin] [-pubout] [-text]

The ec command processes EC keys. They can be converted between various forms and their components printed out. openssl uses the private key format specified in “SEC 1: Elliptic Curve Cryptography” (https://www.secg.org/). To convert an EC private key into the PKCS#8 private key format use the pkcs8 command.

The options are as follows:

-conv_form arg
    Specify how the points on the elliptic curve are converted into octet strings. Possible values are: compressed, uncompressed (the default), and hybrid. For more information regarding the point conversion forms see the X9.62 standard. Note: Due to patent issues the compressed option is disabled by default for binary curves and can be enabled by defining the preprocessor macro OPENSSL_EC_BIN_PT_COMP at compile time.

-des | -des3
    Encrypt the private key with DES, triple DES, or any other cipher supported by openssl. A pass phrase is prompted for. If none of these options are specified, the key is written in plain text. This means that using the ec utility to read in an encrypted key with no encryption option can be used to remove the pass phrase from a key, or by setting the encryption options it can be used to add or change the pass phrase. These options can only be used with PEM format output files.

-in file
    The input file to read a key from, or standard input if not specified. If the key is encrypted, a pass phrase will be prompted for.

-inform der | pem
    The input format.

-noout
    Do not output the encoded version of the key.

-out file
    The output filename to write to, or standard output if not specified. If any encryption options are set then a pass phrase will be prompted for.

-outform der | pem
    The output format.

-param_enc arg
    Specify how the elliptic curve parameters are encoded. Possible value are: named_curve, i.e. the EC parameters are specified by an OID; or explicit, where the EC parameters are explicitly given (see RFC 3279 for the definition of the EC parameter structures). The default value is named_curve. Note: the implicitlyCA alternative, as specified in RFC 3279, is currently not implemented.

-param_out
    Print the elliptic curve parameters.

-passin arg
    The key password source.

-passout arg
    The output file password source.

-pubin
    Read in a public key, not a private key.

-pubout
    Output a public key, not a private key. Automatically set if the input is a public key.

-text
    Print the public/private key in plain text.

ECPARAM

openssl ecparam
    [-C] [-check] [-conv_form arg] [-genkey] [-in file] [-inform der | pem] [-list_curves] [-name arg] [-no_seed] [-noout] [-out file] [-outform der | pem] [-param_enc arg] [-text]

The ecparam command is used to manipulate or generate EC parameter files. openssl is not able to generate new groups so ecparam can only create EC parameters from known (named) curves.

The options are as follows:

-C  Convert the EC parameters into C code. The parameters can then be loaded by calling the get_ec_group_XXX function.

-check
    Validate the elliptic curve parameters.

-conv_form arg
    Specify how the points on the elliptic curve are converted into octet strings. Possible values are: compressed, uncompressed (the default), and hybrid. For more information regarding the point conversion forms see the X9.62 standard. Note: Due to patent issues the compressed option is disabled by default for binary curves and can be enabled by defining the preprocessor macro OPENSSL_EC_BIN_PT_COMP at compile time.

-genkey
    Generate an EC private key using the specified parameters.

-in file
    The input file to read from, or standard input if not specified.

-inform der | pem
    The input format.

-list_curves
    Print a list of all currently implemented EC parameter names and exit.

-name arg
    Use the EC parameters with the specified "short" name.

-no_seed
    Do not include the seed for the parameter generation in the ECParameters structure (see RFC 3279).

-noout
    Do not output the encoded version of the parameters.

-out file
    The output file to write to, or standard output if not specified.

-outform der | pem
    The output format.

-param_enc arg
    Specify how the elliptic curve parameters are encoded. Possible value are: named_curve, i.e. the EC parameters are specified by an OID, or explicit, where the EC parameters are explicitly given (see RFC 3279 for the definition of the EC parameter structures). The default value is named_curve. Note: the implicitlyCA alternative, as specified in RFC 3279, is currently not implemented.

-text
    Print the EC parameters in plain text.

ENC

openssl enc
    -ciphername [-AadePpv] [-base64] [-bufsize number] [-debug] [-in file] [-iter iterations] [-iv IV] [-K key] [-k password] [-kfile file] [-md digest] [-none] [-nopad] [-nosalt] [-out file] [-pass arg] [-pbkdf2] [-S salt] [-salt]

The symmetric cipher commands allow data to be encrypted or decrypted using various block and stream ciphers using keys based on passwords or explicitly provided. Base64 encoding or decoding can also be performed either by itself or in addition to the encryption or decryption. The program can be called either as openssl ciphername or openssl enc -ciphername.

Some of the ciphers do not have large keys and others have security implications if not used correctly. All the block ciphers normally use PKCS#5 padding, also known as standard block padding. If padding is disabled, the input data must be a multiple of the cipher block length.

The options are as follows:

-A  If the -a option is set, then base64 process the data on one line.

-a, -base64
    Base64 process the data. This means that if encryption is taking place, the data is base64-encoded after encryption. If decryption is set, the input data is base64-decoded before being decrypted.

-bufsize number
    Set the buffer size for I/O.

-d  Decrypt the input data.

-debug
    Debug the BIOs used for I/O.

-e  Encrypt the input data. This is the default.

-in file
    The input file to read from, or standard input if not specified.

-iter iterations
    Use the pbkdf2 key derivation function, with iterations as the number of iterations.

-iv IV
    The actual IV (initialisation vector) to use: this must be represented as a string comprised only of hex digits. When only the key is specified using the -K option, the IV must explicitly be defined. When a password is being specified using one of the other options, the IV is generated from this password.

-K key
    The actual key to use: this must be represented as a string comprised only of hex digits. If only the key is specified, the IV must also be specified using the -iv option. When both a key and a password are specified, the key given with the -K option will be used and the IV generated from the password will be taken. It probably does not make much sense to specify both key and password.

-k password
    The password to derive the key from. Superseded by the -pass option.

-kfile file
    Read the password to derive the key from the first line of file. Superseded by the -pass option.

-md digest
    Use digest to create a key from a pass phrase. Currently, the default value is sha256.

-none
    Use NULL cipher (no encryption or decryption of input).

-nopad
    Disable standard block padding.

-nosalt
    Don't use a salt in the key derivation routines. This option should never be used since it makes it possible to perform efficient dictionary attacks on the password and to attack stream cipher encrypted data.

-out file
    The output file to write to, or standard output if not specified.

-P  Print out the salt, key, and IV used, then immediately exit; don't do any encryption or decryption.

-p  Print out the salt, key, and IV used.

-pass arg
    The password source.

-pbkdf2
    Use the pbkdf2 key derivation function, with the default of 10000 iterations.

-S salt
    The actual salt to use: this must be represented as a string comprised only of hex digits.

-salt
    Use a salt in the key derivation routines (the default). When the salt is being used, the first eight bytes of the encrypted data are reserved for the salt: it is randomly generated when encrypting a file and read from the encrypted file when it is decrypted.

-v  Print extra details about the processing.

ERRSTR
openssl errstr [-stats] errno ...

The errstr command performs error number to error string conversion, generating a human-readable string representing the error code errno. The string is obtained through the ERR_error_string_n(3) function and has the following format:

    error:[error code]:[library name]:[function name]:[reason string]

[error code] is an 8-digit hexadecimal number. The remaining fields [library name], [function name], and [reason string] are all ASCII text.

The options are as follows:

-stats
    Print debugging statistics about various aspects of the hash table.

GENDSA

openssl gendsa
    [ -aes128 | -aes192 | -aes256 | -camellia128 | -camellia192 | -camellia256 | -des | -des3 | -idea] [-out file] [-passout arg] paramfile

The gendsa command generates a DSA private key from a DSA parameter file (typically generated by the openssl dsaparam command). DSA key generation is little more than random number generation so it is much quicker than, for example, RSA key generation.

The options are as follows:

    -aes128 | -aes192 | -aes256 | -camellia128 | -camellia192 | -camellia256 | -des | -des3 | -idea Encrypt the private key with the AES, CAMELLIA, DES, triple DES or the IDEA ciphers, respectively, before outputting it. A pass phrase is prompted for. If none of these options are specified, no encryption is used.

-out file
    The output file to write to, or standard output if not specified.

-passout arg
    The output file password source.

paramfile
    Specify the DSA parameter file to use. The parameters in this file determine the size of the private key.

GENPKEY

openssl genpkey
    [-algorithm alg] [cipher] [-genparam] [-out file] [-outform der | pem] [-paramfile file] [-pass arg] [-pkeyopt opt:value] [-text]

The genpkey command generates private keys. The use of this program is encouraged over the algorithm specific utilities because additional algorithm options can be used.

The options are as follows:

-algorithm alg
    The public key algorithm to use, such as RSA, DSA, or DH. This option must precede any -pkeyopt options. The options -paramfile and -algorithm are mutually exclusive.

cipher
    Encrypt the private key with the supplied cipher. Any algorithm name accepted by EVP_get_cipherbyname(3) is acceptable.

-genparam
    Generate a set of parameters instead of a private key. This option must precede any -algorithm, -paramfile, or -pkeyopt options.

-out file
    The output file to write to, or standard output if not specified.

-outform der | pem
    The output format.

-paramfile file
    Some public key algorithms generate a private key based on a set of parameters, which can be supplied using this option. If this option is used, the public key algorithm used is determined by the parameters. This option must precede any -pkeyopt options. The options -paramfile and -algorithm are mutually exclusive.

-pass arg
    The output file password source.

-pkeyopt opt:value
    Set the public key algorithm option opt to value, as follows:

    rsa_keygen_bits:numbits
        (RSA) The number of bits in the generated key. The default is 2048.

    rsa_keygen_pubexp:value
        (RSA) The RSA public exponent value. This can be a large decimal or hexadecimal value if preceded by 0x. The default is 65537.

    dsa_paramgen_bits:numbits
        (DSA) The number of bits in the generated parameters. The default is 1024.

    dh_paramgen_prime_len:numbits
        (DH) The number of bits in the prime parameter p.

    dh_paramgen_generator:value
        (DH) The value to use for the generator g.

    ec_paramgen_curve:curve
        (EC) The elliptic curve to use.

-text
    Print the private/public key in plain text.

GENRSA

openssl genrsa
    [-3 | -f4] [ -aes128 | -aes192 | -aes256 | -camellia128 | -camellia192 | -camellia256 | -des | -des3 | -idea] [-out file] [-passout arg] [numbits]

The genrsa command generates an RSA private key, which essentially involves the generation of two prime numbers. When generating the key, various symbols will be output to indicate the progress of the generation. A ‘’. represents each number which has passed an initial sieve test; ‘+’ means a number has passed a single round of the Miller-Rabin primality test; ‘*’ means the number has failed primality testing and needs to be generated afresh. A newline means that the number has passed all the prime tests (the actual number depends on the key size).

The options are as follows:

-3 | -f4
    The public exponent to use, either 3 or 65537. The default is 65537.

    -aes128 | -aes192 | -aes256 | -camellia128 | -camellia192 | -camellia256 | -des | -des3 | -idea Encrypt the private key with the AES, CAMELLIA, DES, triple DES or the IDEA ciphers, respectively, before outputting it. If none of these options are specified, no encryption is used. If encryption is used, a pass phrase is prompted for, if it is not supplied via the -passout option.

-out file
    The output file to write to, or standard output if not specified.

-passout arg
    The output file password source.

numbits
    The size of the private key to generate in bits. This must be the last option specified. The default is 2048.

OCSP

openssl ocsp
    [-CA file] [-CAfile file] [-CApath directory] [-cert file] [-dgst alg] [-header name value] [-host hostname:port] [-ignore_err] [-index indexfile] [-issuer file] [-ndays days] [-nmin minutes] [-no_cert_checks] [-no_cert_verify] [-no_certs] [-no_chain] [-no_explicit] [-no_intern] [-no_nonce] [-no_signature_verify] [-nonce] [-noverify] [-nrequest number] [-out file] [-path path] [-port portnum] [-req_text] [-reqin file] [-reqout file] [-resp_key_id] [-resp_no_certs] [-resp_text] [-respin file] [-respout file] [-rkey file] [-rother file] [-rsigner file] [-serial num] [-sign_other file] [-signer file] [-signkey file] [-status_age age] [-text] [-timeout seconds] [-trust_other] [-url responder_url] [-VAfile file] [-validity_period nsec] [-verify_other file]

The Online Certificate Status Protocol (OCSP) enables applications to determine the (revocation) state of an identified certificate (RFC 2560).

The ocsp command performs many common OCSP tasks. It can be used to print out requests and responses, create requests and send queries to an OCSP responder, and behave like a mini OCSP server itself.

The options are as follows:

-CAfile file, -CApath directory
    A file or path containing trusted CA certificates, used to verify the signature on the OCSP response.

-cert file
    Add the certificate file to the request. The issuer certificate is taken from the previous -issuer option, or an error occurs if no issuer certificate is specified.

-dgst alg
    Use the digest algorithm alg for certificate identification in the OCSP request. By default SHA1 is used.

    -host hostname:port, -path path Send the OCSP request to hostname on port. -path specifies the HTTP path name to use, or / by default.

-header name value
    Add the header name with the specified value to the OCSP request that is sent to the responder. This may be repeated.

-issuer file
    The current issuer certificate, in PEM format. Can be used multiple times and must come before any -cert options.

-no_cert_checks
    Don't perform any additional checks on the OCSP response signer's certificate. That is, do not make any checks to see if the signer's certificate is authorised to provide the necessary status information: as a result this option should only be used for testing purposes.

-no_cert_verify
    Don't verify the OCSP response signer's certificate at all. Since this option allows the OCSP response to be signed by any certificate, it should only be used for testing purposes.

-no_certs
    Don't include any certificates in the signed request.

-no_chain
    Do not use certificates in the response as additional untrusted CA certificates.

-no_explicit
    Don't check the explicit trust for OCSP signing in the root CA certificate.

-no_intern
    Ignore certificates contained in the OCSP response when searching for the signer's certificate. The signer's certificate must be specified with either the -verify_other or -VAfile options.

-no_signature_verify
    Don't check the signature on the OCSP response. Since this option tolerates invalid signatures on OCSP responses, it will normally only be used for testing purposes.

-nonce, -no_nonce
    Add an OCSP nonce extension to a request, or disable an OCSP nonce addition. Normally, if an OCSP request is input using the -respin option no nonce is added: using the -nonce option will force the addition of a nonce. If an OCSP request is being created (using the -cert and -serial options), a nonce is automatically added; specifying -no_nonce overrides this.

-noverify
    Don't attempt to verify the OCSP response signature or the nonce values. This is normally only be used for debugging since it disables all verification of the responder's certificate.

-out file
    Specify the output file to write to, or standard output if not specified.

-req_text, -resp_text, -text
    Print out the text form of the OCSP request, response, or both, respectively.

-reqin file, -respin file
    Read an OCSP request or response file from file. These options are ignored if an OCSP request or response creation is implied by other options (for example with the -serial, -cert, and -host options).

-reqout file, -respout file
    Write out the DER-encoded certificate request or response to file.

-serial num
    Same as the -cert option except the certificate with serial number num is added to the request. The serial number is interpreted as a decimal integer unless preceded by ‘0x’. Negative integers can also be specified by preceding the value with a minus sign.

-sign_other file
    Additional certificates to include in the signed request.

-signer file, -signkey file
    Sign the OCSP request using the certificate specified in the -signer option and the private key specified by the -signkey option. If the -signkey option is not present, then the private key is read from the same file as the certificate. If neither option is specified, the OCSP request is not signed.

-timeout seconds
    Connection timeout to the OCSP responder in seconds.

-trust_other
    The certificates specified by the -verify_other option should be explicitly trusted and no additional checks will be performed on them. This is useful when the complete responder certificate chain is not available or trusting a root CA is not appropriate.

-url responder_url
    Specify the responder URL. Both HTTP and HTTPS (SSL/TLS) URLs can be specified.

-VAfile file
    A file containing explicitly trusted responder certificates. Equivalent to the -verify_other and -trust_other options.

-validity_period nsec, -status_age age
    The range of times, in seconds, which will be tolerated in an OCSP response. Each certificate status response includes a notBefore time and an optional notAfter time. The current time should fall between these two values, but the interval between the two times may be only a few seconds. In practice the OCSP responder and clients' clocks may not be precisely synchronised and so such a check may fail. To avoid this the -validity_period option can be used to specify an acceptable error range in seconds, the default value being 5 minutes.

    If the notAfter time is omitted from a response, it means that new status information is immediately available. In this case the age of the notBefore field is checked to see it is not older than age seconds old. By default, this additional check is not performed.

-verify_other file
    A file containing additional certificates to search when attempting to locate the OCSP response signing certificate. Some responders omit the actual signer's certificate from the response, so this can be used to supply the necessary certificate.

The options for the OCSP server are as follows:

-CA file
    CA certificate corresponding to the revocation information in indexfile.

-ignore_err
    Ignore the invalid response.

-index indexfile
    indexfile is a text index file in ca format containing certificate revocation information.

    If this option is specified, ocsp is in responder mode, otherwise it is in client mode. The requests the responder processes can be either specified on the command line (using the -issuer and -serial options), supplied in a file (using the -respin option), or via external OCSP clients (if port or url is specified).

    If this option is present, then the -CA and -rsigner options must also be present.

-nmin minutes, -ndays days
    Number of minutes or days when fresh revocation information is available: used in the nextUpdate field. If neither option is present, the nextUpdate field is omitted, meaning fresh revocation information is immediately available.

-nrequest number
    Exit after receiving number requests (the default is unlimited).

-port portnum
    Port to listen for OCSP requests on. May also be specified using the -url option.

-resp_key_id
    Identify the signer certificate using the key ID; the default is to use the subject name.

-resp_no_certs
    Don't include any certificates in the OCSP response.

-rkey file
    The private key to sign OCSP responses with; if not present, the file specified in the -rsigner option is used.

-rother file
    Additional certificates to include in the OCSP response.

-rsigner file
    The certificate to sign OCSP responses with.

Initially the OCSP responder certificate is located and the signature on the OCSP request checked using the responder certificate's public key. Then a normal certificate verify is performed on the OCSP responder certificate building up a certificate chain in the process. The locations of the trusted certificates used to build the chain can be specified by the -CAfile and -CApath options or they will be looked for in the standard openssl certificates directory.

If the initial verify fails, the OCSP verify process halts with an error. Otherwise the issuing CA certificate in the request is compared to the OCSP responder certificate: if there is a match then the OCSP verify succeeds.

Otherwise the OCSP responder certificate's CA is checked against the issuing CA certificate in the request. If there is a match and the OCSPSigning extended key usage is present in the OCSP responder certificate, then the OCSP verify succeeds.

Otherwise the root CA of the OCSP responder's CA is checked to see if it is trusted for OCSP signing. If it is, the OCSP verify succeeds.

If none of these checks is successful, the OCSP verify fails. What this effectively means is that if the OCSP responder certificate is authorised directly by the CA it is issuing revocation information about (and it is correctly configured), then verification will succeed.

If the OCSP responder is a global responder, which can give details about multiple CAs and has its own separate certificate chain, then its root CA can be trusted for OCSP signing. Alternatively, the responder certificate itself can be explicitly trusted with the -VAfile option.

PASSWD

openssl passwd
    [-1 | -apr1 | -crypt] [-in file] [-noverify] [-quiet] [-reverse] [-salt string] [-stdin] [-table] [password]

The passwd command computes the hash of a password.

The options are as follows:

-1  Use the MD5 based BSD password algorithm "1".

-apr1
    Use the "apr1" algorithm ( Apache variant of the BSD algorithm).

-crypt
    Use the "crypt" algorithm (the default).

-in file
    Read passwords from file.

-noverify
    Don't verify when reading a password from the terminal.

-quiet
    Don't output warnings when passwords given on the command line are truncated.

-reverse
    Switch table columns. This only makes sense in conjunction with the -table option.

-salt string
    Use the salt specified by string. When reading a password from the terminal, this implies -noverify.

-stdin
    Read passwords from standard input.

-table
    In the output list, prepend the cleartext password and a TAB character to each password hash.

PKCS7

openssl pkcs7
    [-in file] [-inform der | pem] [-noout] [-out file] [-outform der | pem] [-print] [-print_certs] [-text]

The pkcs7 command processes PKCS#7 files in DER or PEM format. The PKCS#7 routines only understand PKCS#7 v 1.5 as specified in RFC 2315.

The options are as follows:

-in file
    The input file to read from, or standard input if not specified.

-inform der | pem
    The input format.

-noout
    Don't output the encoded version of the PKCS#7 structure (or certificates if -print_certs is set).

-out file
    The output to write to, or standard output if not specified.

-outform der | pem
    The output format.

-print
    Print the ASN.1 representation of PKCS#7 structure.

-print_certs
    Print any certificates or CRLs contained in the file, preceded by their subject and issuer names in a one-line format.

-text
    Print certificate details in full rather than just subject and issuer names.

PKCS8

openssl pkcs8
    [-in file] [-inform der | pem] [-nocrypt] [-noiter] [-out file] [-outform der | pem] [-passin arg] [-passout arg] [-topk8] [-v1 alg] [-v2 alg]

The pkcs8 command processes private keys (both encrypted and unencrypted) in PKCS#8 format with a variety of PKCS#5 (v1.5 and v2.0) and PKCS#12 algorithms. The default encryption is only 56 bits; keys encrypted using PKCS#5 v2.0 algorithms and high iteration counts are more secure.

The options are as follows:

-in file
    The input file to read from, or standard input if not specified. If the key is encrypted, a pass phrase will be prompted for.

-inform der | pem
    The input format.

-nocrypt
    Generate an unencrypted PrivateKeyInfo structure. This option does not encrypt private keys at all and should only be used when absolutely necessary.

-noiter
    Use an iteration count of 1. See the PKCS12 section below for a detailed explanation of this option.

-out file
    The output file to write to, or standard output if none is specified. If any encryption options are set, a pass phrase will be prompted for.

-outform der | pem
    The output format.

-passin arg
    The key password source.

-passout arg
    The output file password source.

-topk8
    Read a traditional format private key and write a PKCS#8 format key.

-v1 alg
    Specify a PKCS#5 v1.5 or PKCS#12 algorithm to use.

    PBE-MD5-DES
        56-bit DES.
    PBE-SHA1-RC2-64 | PBE-MD5-RC2-64 | PBE-SHA1-DES
        64-bit RC2 or 56-bit DES.
    PBE-SHA1-RC4-128 | PBE-SHA1-RC4-40 | PBE-SHA1-3DES
    PBE-SHA1-2DES | PBE-SHA1-RC2-128 | PBE-SHA1-RC2-40
        PKCS#12 password-based encryption algorithm, which allow strong encryption algorithms like triple DES or 128-bit RC2.

-v2 alg
    Use PKCS#5 v2.0 algorithms. Supports algorithms such as 168-bit triple DES or 128-bit RC2, however not many implementations support PKCS#5 v2.0 yet (if using private keys with openssl this doesn't matter).

    alg is the encryption algorithm to use; valid values include des, des3, and rc2. It is recommended that des3 is used.

PKCS12

openssl pkcs12
    [ -aes128 | -aes192 | -aes256 | -camellia128 | -camellia192 | -camellia256 | -des | -des3 | -idea] [-cacerts] [-CAfile file] [-caname name] [-CApath directory] [-certfile file] [-certpbe alg] [-chain] [-clcerts] [-CSP name] [-descert] [-export] [-in file] [-info] [-inkey file] [-keyex] [-keypbe alg] [-keysig] [-LMK] [-macalg alg] [-maciter] [-name name] [-nocerts] [-nodes] [-noiter] [-nokeys] [-nomac] [-nomaciter] [-nomacver] [-noout] [-out file] [-passin arg] [-passout arg] [-password arg] [-twopass]

The pkcs12 command allows PKCS#12 files (sometimes referred to as PFX files) to be created and parsed. By default, a PKCS#12 file is parsed; a PKCS#12 file can be created by using the -export option.

The options for parsing a PKCS12 file are as follows:

    -aes128 | -aes192 | -aes256 | -camellia128 | -camellia192 | -camellia256 | -des | -des3 | -idea Encrypt private keys using AES, CAMELLIA, DES, triple DES or the IDEA ciphers, respectively. The default is triple DES.

-cacerts
    Only output CA certificates (not client certificates).

-clcerts
    Only output client certificates (not CA certificates).

-in file
    The input file to read from, or standard input if not specified.

-info
    Output additional information about the PKCS#12 file structure, algorithms used, and iteration counts.

-nocerts
    Do not output certificates.

-nodes
    Do not encrypt private keys.

-nokeys
    Do not output private keys.

-nomacver
    Do not attempt to verify the integrity MAC before reading the file.

-noout
    Do not output the keys and certificates to the output file version of the PKCS#12 file.

-out file
    The output file to write to, or standard output if not specified.

-passin arg
    The key password source.

-passout arg
    The output file password source.

-twopass
    Prompt for separate integrity and encryption passwords: most software always assumes these are the same so this option will render such PKCS#12 files unreadable.

The options for PKCS12 file creation are as follows:

-CAfile file
    CA storage as a file.

-CApath directory
    CA storage as a directory. The directory must be a standard certificate directory: that is, a hash of each subject name (using x509 -hash) should be linked to each certificate.

-caname name
    Specify the "friendly name" for other certificates. May be used multiple times to specify names for all certificates in the order they appear.

-certfile file
    A file to read additional certificates from.

-certpbe alg, -keypbe alg
    Specify the algorithm used to encrypt the private key and certificates to be selected. Any PKCS#5 v1.5 or PKCS#12 PBE algorithm name can be used. If a cipher name (as output by the list-cipher-algorithms command) is specified then it is used with PKCS#5 v2.0. For interoperability reasons it is advisable to only use PKCS#12 algorithms.

-chain
    Include the entire certificate chain of the user certificate. The standard CA store is used for this search. If the search fails, it is considered a fatal error.

-CSP name
    Write name as a Microsoft CSP name.

-descert
    Encrypt the certificate using triple DES; this may render the PKCS#12 file unreadable by some "export grade" software. By default, the private key is encrypted using triple DES and the certificate using 40-bit RC2.

-export
    Create a PKCS#12 file (rather than parsing one).

-in file
    The input file to read from, or standard input if not specified. The order doesn't matter but one private key and its corresponding certificate should be present. If additional certificates are present, they will also be included in the PKCS#12 file.

-inkey file
    File to read a private key from. If not present, a private key must be present in the input file.

-keyex | -keysig
    Specify whether the private key is to be used for key exchange or just signing. Normally, "export grade" software will only allow 512-bit RSA keys to be used for encryption purposes, but arbitrary length keys for signing. The -keysig option marks the key for signing only. Signing only keys can be used for S/MIME signing, authenticode (ActiveX control signing) and SSL client authentication.

-LMK
    Add local machine keyset attribute to private key.

-macalg alg
    Specify the MAC digest algorithm. The default is SHA1.

-maciter
    Included for compatibility only: it used to be needed to use MAC iterations counts but they are now used by default.

-name name
    Specify the "friendly name" for the certificate and private key. This name is typically displayed in list boxes by software importing the file.

-nomac
    Don't attempt to provide the MAC integrity.

-nomaciter, -noiter
    Affect the iteration counts on the MAC and key algorithms.

    To discourage attacks by using large dictionaries of common passwords, the algorithm that derives keys from passwords can have an iteration count applied to it: this causes a certain part of the algorithm to be repeated and slows it down. The MAC is used to check the file integrity but since it will normally have the same password as the keys and certificates it could also be attacked. By default, both MAC and encryption iteration counts are set to 2048; using these options the MAC and encryption iteration counts can be set to 1. Since this reduces the file security, you should not use these options unless you really have to. Most software supports both MAC and key iteration counts.

-out file
    The output file to write to, or standard output if not specified.

-passin arg
    The key password source.

-passout arg
    The output file password source.

-password arg
    With -export, -password is equivalent to -passout. Otherwise, -password is equivalent to -passin.

PKEY

openssl pkey
    [-check] [cipher] [-in file] [-inform der | pem] [-noout] [-out file] [-outform der | pem] [-passin arg] [-passout arg] [-pubcheck] [-pubin] [-pubout] [-text] [-text_pub]

The pkey command processes public or private keys. They can be converted between various forms and their components printed out.

The options are as follows:

-check
    Check the validity of a key pair.

cipher
    Encrypt the private key with the specified cipher. Any algorithm name accepted by EVP_get_cipherbyname(3) is acceptable, such as des3.

-in file
    The input file to read from, or standard input if not specified. If the key is encrypted, a pass phrase will be prompted for.

-inform der | pem
    The input format.

-noout
    Do not output the encoded version of the key.

-out file
    The output file to write to, or standard output if not specified. If any encryption options are set then a pass phrase will be prompted for.

-outform der | pem
    The output format.

-passin arg
    The key password source.

-passout arg
    The output file password source.

-pubcheck
    Check the validity of a public key or the public component of a key pair.

-pubin
    Read in a public key, not a private key.

-pubout
    Output a public key, not a private key. Automatically set if the input is a public key.

-text
    Print the public/private key in plain text.

-text_pub
    Print out only public key components even if a private key is being processed.

PKEYPARAM
openssl pkeyparam [-check] [-in file] [-noout] [-out file] [-text]

The pkeyparam command processes public or private keys. The key type is determined by the PEM headers.

The options are as follows:

-check
    check the correctness of parameters.

-in file
    The input file to read from, or standard input if not specified.

-noout
    Do not output the encoded version of the parameters.

-out file
    The output file to write to, or standard output if not specified.

-text
    Print the parameters in plain text.

PKEYUTL

openssl pkeyutl
    [-asn1parse] [-certin] [-decrypt] [-derive] [-encrypt] [-hexdump] [-in file] [-inkey file] [-keyform der | pem] [-out file] [-passin arg] [-peerform der | pem] [-peerkey file] [-pkeyopt opt:value] [-pubin] [-rev] [-sigfile file] [-sign] [-verify] [-verifyrecover]

The pkeyutl command can be used to perform public key operations using any supported algorithm.

The options are as follows:

-asn1parse
    ASN.1 parse the output data. This is useful when combined with the -verifyrecover option when an ASN.1 structure is signed.

-certin
    The input is a certificate containing a public key.

-decrypt
    Decrypt the input data using a private key.

-derive
    Derive a shared secret using the peer key.

-encrypt
    Encrypt the input data using a public key.

-hexdump
    Hex dump the output data.

-in file
    The input file to read from, or standard input if not specified.

-inkey file
    The input key file. By default it should be a private key.

-keyform der | pem
    The key format.

-out file
    The output file to write to, or standard output if not specified.

-passin arg
    The key password source.

-peerform der | pem
    The peer key format.

-peerkey file
    The peer key file, used by key derivation (agreement) operations.

-pkeyopt opt:value
    Set the public key algorithm option opt to value. Unless otherwise mentioned, all algorithms support the format digest:alg, which specifies the digest to use for sign, verify, and verifyrecover operations. The value alg should represent a digest name as used in the EVP_get_digestbyname(3) function.

    The RSA algorithm supports the encrypt, decrypt, sign, verify, and verifyrecover operations in general. Some padding modes only support some of these operations however.

    rsa_padding_mode:mode
        This sets the RSA padding mode. Acceptable values for mode are pkcs1 for PKCS#1 padding; none for no padding; oaep for OAEP mode; x931 for X9.31 mode; and pss for PSS.

        In PKCS#1 padding if the message digest is not set then the supplied data is signed or verified directly instead of using a DigestInfo structure. If a digest is set then a DigestInfo structure is used and its length must correspond to the digest type. For oeap mode only encryption and decryption is supported. For x931 if the digest type is set it is used to format the block data; otherwise the first byte is used to specify the X9.31 digest ID. Sign, verify, and verifyrecover can be performed in this mode. For pss mode only sign and verify are supported and the digest type must be specified.

    rsa_pss_saltlen:len
        For pss mode only this option specifies the salt length. Two special values are supported: -1 sets the salt length to the digest length. When signing, -2 sets the salt length to the maximum permissible value. When verifying, -2 causes the salt length to be automatically determined based on the PSS block structure.

    The DSA algorithm supports the sign and verify operations. Currently there are no additional options other than digest. Only the SHA1 digest can be used and this digest is assumed by default.

    The DH algorithm supports the derive operation and no additional options.

    The EC algorithm supports the sign, verify, and derive operations. The sign and verify operations use ECDSA and derive uses ECDH. Currently there are no additional options other than digest. Only the SHA1 digest can be used and this digest is assumed by default.

-pubin
    The input file is a public key.

-rev
    Reverse the order of the input buffer.

-sigfile file
    Signature file (verify operation only).

-sign
    Sign the input data and output the signed result. This requires a private key.

-verify
    Verify the input data against the signature file and indicate if the verification succeeded or failed.

-verifyrecover
    Verify the input data and output the recovered data.

PRIME
openssl prime [-bits n] [-checks n] [-generate] [-hex] [-safe] p

The prime command is used to generate prime numbers, or to check numbers for primality. Results are probabilistic: they have an exceedingly high likelihood of being correct, but are not guaranteed.

The options are as follows:

-bits n
    Specify the number of bits in the generated prime number. Must be used in conjunction with -generate.

-checks n
    Perform a Miller-Rabin probabilistic primality test with n iterations. The default is 20.

-generate
    Generate a pseudo-random prime number. Must be used in conjunction with -bits.

-hex
    Output in hex format.

-safe
    Generate only "safe" prime numbers (i.e. a prime p so that (p-1)/2 is also prime).

p   Test if number p is prime.

RAND

openssl rand
    [-base64] [-hex] [-out file] num

The rand command outputs num pseudo-random bytes.

The options are as follows:

-base64
    Perform base64 encoding on the output.

-hex
    Specify hexadecimal output.

-out file
    The output file to write to, or standard output if not specified.

REQ

openssl req
    [-addext ext] [-batch] [-config file] [-days n] [-extensions section] [-in file] [-inform der | pem] [-key keyfile] [-keyform der | pem] [-keyout file] [-md4 | -md5 | -sha1] [-modulus] [-multivalue-rdn] [-nameopt option] [-new] [-newhdr] [-newkey arg] [-nodes] [-noout] [-out file] [-outform der | pem] [-passin arg] [-passout arg] [-pkeyopt opt:value] [-pubkey] [-reqexts section] [-reqopt option] [-set_serial n] [-sigopt nm:v] [-subj arg] [-subject] [-text] [-utf8] [-verbose] [-verify] [-x509]

The req command primarily creates and processes certificate requests in PKCS#10 format. It can additionally create self-signed certificates, for use as root CAs, for example.

The options are as follows:

-addext ext
    Add a specific extension to the certificate (if the -x509 option is present) or certificate request. The argument must have the form of a key=value pair as it would appear in a config file. This option can be given multiple times.

-batch
    Non-interactive mode.

-config file
    Specify an alternative configuration file.

-days n
    Specify the number of days to certify the certificate for. The default is 30 days. Used with the -x509 option.

-extensions section, -reqexts section
    Specify alternative sections to include certificate extensions (with -x509) or certificate request extensions, allowing several different sections to be used in the same configuration file.

-in file
    The input file to read a request from, or standard input if not specified. A request is only read if the creation options -new and -newkey are not specified.

-inform der | pem
    The input format.

-key keyfile
    The file to read the private key from. It also accepts PKCS#8 format private keys for PEM format files.

-keyform der | pem
    The format of the private key file specified in the -key argument. The default is pem.

-keyout file
    The file to write the newly created private key to. If this option is not specified, the filename present in the configuration file is used.

-md5 | -sha1 | -sha256
    The message digest to sign the request with. This overrides the digest algorithm specified in the configuration file.

    Some public key algorithms may override this choice. For instance, DSA signatures always use SHA1.

-modulus
    Print the value of the modulus of the public key contained in the request.

-multivalue-rdn
    This option causes the -subj argument to be interpreted with full support for multivalued RDNs, for example "/DC=org/DC=OpenSSL/DC=users/UID=123456+CN=John Doe". If -multivalue-rdn is not used, the UID value is set to "123456+CN=John Doe".

-nameopt option, -reqopt option
    Determine how the subject or issuer names are displayed. option can be a single option or multiple options separated by commas. Alternatively, these options may be used more than once to set multiple options. See the X509 section below for details.

-new
    Generate a new certificate request. The user is prompted for the relevant field values. The actual fields prompted for and their maximum and minimum sizes are specified in the configuration file and any requested extensions.

    If the -key option is not used, it will generate a new RSA private key using information specified in the configuration file.

-newhdr
    Add the word NEW to the PEM file header and footer lines on the outputted request. Some software and CAs need this.

-newkey arg
    Create a new certificate request and a new private key. The argument takes one of several forms.

    rsa:nbits generates an RSA key nbits in size. If nbits is omitted, the default key size is used.

    dsa:file generates a DSA key using the parameters in file.

    param:file generates a key using the parameters or certificate in file.

    All other algorithms support the form algorithm:file, where file may be an algorithm parameter file, created by the genpkey -genparam command or an X.509 certificate for a key with appropriate algorithm. file can be omitted, in which case any parameters can be specified via the -pkeyopt option.

-nodes
    Do not encrypt the private key.

-noout
    Do not output the encoded version of the request.

-out file
    The output file to write to, or standard output if not specified.

-outform der | pem
    The output format.

-passin arg
    The key password source.

-passout arg
    The output file password source.

-pkeyopt opt:value
    Set the public key algorithm option opt to value.

-pubkey
    Output the public key.

-reqopt option
    Customise the output format used with -text. The option argument can be a single option or multiple options separated by commas. See also the discussion of -certopt in the x509 command.

-set_serial n
    Serial number to use when outputting a self-signed certificate. This may be specified as a decimal value or a hex value if preceded by ‘0x’. It is possible to use negative serial numbers but this is not recommended.

-sigopt nm:v
    Pass options to the signature algorithm during sign operation. The names and values of these options are algorithm-specific.

-subj arg
    Replaces the subject field of an input request with the specified data and output the modified request. arg must be formatted as /type0=value0/type1=value1/type2=...; characters may be escaped by ‘\’ (backslash); no spaces are skipped.

-subject
    Print the request subject (or certificate subject if -x509 is specified).

-text
    Print the certificate request in plain text.

-utf8
    Interpret field values as UTF8 strings, not ASCII.

-verbose
    Print extra details about the operations being performed.

-verify
    Verify the signature on the request.

-x509
    Output a self-signed certificate instead of a certificate request. This is typically used to generate a test certificate or a self-signed root CA. The extensions added to the certificate (if any) are specified in the configuration file. Unless specified using the -set_serial option, 0 is used for the serial number.

The configuration options are specified in the "req" section of the configuration file. The options available are as follows:

attributes
    The section containing any request attributes: its format is the same as distinguished_name. Typically these may contain the challengePassword or unstructuredName types. They are currently ignored by the openssl request signing utilities, but some CAs might want them.

default_bits
    The default key size, in bits. The default is 2048. It is used if the -new option is used and can be overridden by using the -newkey option.

default_keyfile
    The default file to write a private key to, or standard output if not specified. It can be overridden by the -keyout option.

default_md
    The digest algorithm to use. Possible values include md5, sha1 and sha256 (the default). It can be overridden on the command line.

distinguished_name
    The section containing the distinguished name fields to prompt for when generating a certificate or certificate request. The format is described below.

encrypt_key
    If set to "no" and a private key is generated, it is not encrypted. It is equivalent to the -nodes option. For compatibility, encrypt_rsa_key is an equivalent option.

input_password | output_password
    The passwords for the input private key file (if present) and the output private key file (if one will be created). The command line options -passin and -passout override the configuration file values.

oid_file
    A file containing additional OBJECT IDENTIFIERS. Each line of the file should consist of the numerical form of the object identifier, followed by whitespace, then the short name followed by whitespace and finally the long name.

oid_section
    Specify a section in the configuration file containing extra object identifiers. Each line should consist of the short name of the object identifier followed by ‘=’ and the numerical form. The short and long names are the same when this option is used.

prompt
    If set to "no", it disables prompting of certificate fields and just takes values from the config file directly. It also changes the expected format of the distinguished_name and attributes sections.

req_extensions
    The configuration file section containing a list of extensions to add to the certificate request. It can be overridden by the -reqexts option.

string_mask
    Limit the string types for encoding certain fields. The following values may be used, limiting strings to the indicated types:

    utf8only
        UTF8String. This is the default, as recommended by PKIX in RFC 2459.

    default
        PrintableString, IA5String, T61String, BMPString, UTF8String.

    pkix
        PrintableString, IA5String, BMPString, UTF8String. Inspired by the PKIX recommendation in RFC 2459 for certificates generated before 2004, but differs by also permitting IA5String.

    nombstr
        PrintableString, IA5String, T61String, UniversalString. A workaround for some ancient software that had problems with the variable-sized BMPString and UTF8String types.

    MASK:number
        An explicit bitmask of permitted types, where number is a C-style hex, decimal, or octal number that's a bit-wise OR of B_ASN1_* values from <openssl/asn1.h>.

utf8
    If set to "yes", field values are interpreted as UTF8 strings.

x509_extensions
    The configuration file section containing a list of extensions to add to a certificate generated when the -x509 switch is used. It can be overridden by the -extensions command line switch.

There are two separate formats for the distinguished name and attribute sections. If the -prompt option is set to "no", then these sections just consist of field names and values. If the -prompt option is absent or not set to "no", then the file contains field prompting information of the form:

    fieldName="prompt"
    fieldName_default="default field value"
    fieldName_min= 2
    fieldName_max= 4

"fieldName" is the field name being used, for example commonName (or CN). The "prompt" string is used to ask the user to enter the relevant details. If the user enters nothing, the default value is used; if no default value is present, the field is omitted. A field can still be omitted if a default value is present, if the user just enters the ‘’. character.

The number of characters entered must be between the fieldName_min and fieldName_max limits: there may be additional restrictions based on the field being used (for example countryName can only ever be two characters long and must fit in a PrintableString).

Some fields (such as organizationName) can be used more than once in a DN. This presents a problem because configuration files will not recognize the same name occurring twice. To avoid this problem, if the fieldName contains some characters followed by a full stop, they will be ignored. So, for example, a second organizationName can be input by calling it "1.organizationName".

The actual permitted field names are any object identifier short or long names. These are compiled into openssl and include the usual values such as commonName, countryName, localityName, organizationName, organizationalUnitName, stateOrProvinceName. Additionally, emailAddress is included as well as name, surname, givenName, initials and dnQualifier.

Additional object identifiers can be defined with the oid_file or oid_section options in the configuration file. Any additional fields will be treated as though they were a DirectoryString.

RSA

openssl rsa
    [-aes128 | -aes192 | -aes256 | -des | -des3] [-check] [-in file] [-inform der | net | pem | pvk] [-modulus] [-noout] [-out file] [-outform der | net | pem | pvk] [-passin arg] [-passout arg] [-pubin] [-pubout] [-pvk-none | -pvk-strong | -pvk-weak] [-RSAPublicKey_in] [-RSAPublicKey_out] [-text]

The rsa command processes RSA keys. They can be converted between various forms and their components printed out. rsa uses the traditional SSLeay compatible format for private key encryption: newer applications should use the more secure PKCS#8 format using the pkcs8 utility.

The options are as follows:

-aes128 | -aes192 | -aes256 | -des | -des3
    Encrypt the private key with the AES, DES, or the triple DES ciphers, respectively, before outputting it. A pass phrase is prompted for. If none of these options are specified, the key is written in plain text. This means that using the rsa utility to read in an encrypted key with no encryption option can be used to remove the pass phrase from a key, or by setting the encryption options it can be used to add or change the pass phrase. These options can only be used with PEM format output files.

-check
    Check the consistency of an RSA private key.

-in file
    The input file to read from, or standard input if not specified. If the key is encrypted, a pass phrase will be prompted for.

-inform der | net | pem | pvk
    The input format.

-noout
    Do not output the encoded version of the key.

-modulus
    Print the value of the modulus of the key.

-out file
    The output file to write to, or standard output if not specified.

-outform der | net | pem | pvk
    The output format.

-passin arg
    The key password source.

-passout arg
    The output file password source.

-pubin
    Read in a public key, not a private key.

-pubout
    Output a public key, not a private key. Automatically set if the input is a public key.

    -pvk-none | -pvk-strong | -pvk-weak Enable or disable PVK encoding. The default is -pvk-strong.

-RSAPublicKey_in, -RSAPublicKey_out
    Same as -pubin and -pubout except RSAPublicKey format is used instead.

-text
    Print the public/private key components in plain text.

RSAUTL

openssl rsautl
    [-asn1parse] [-certin] [-decrypt] [-encrypt] [-hexdump] [-in file] [-inkey file] [-keyform der | pem] [-oaep | -pkcs | -raw | -x931] [-out file] [-passin arg] [-pubin] [-rev] [-sign] [-verify]

The rsautl command can be used to sign, verify, encrypt and decrypt data using the RSA algorithm.

The options are as follows:

-asn1parse
    Asn1parse the output data; this is useful when combined with the -verify option.

-certin
    The input is a certificate containing an RSA public key.

-decrypt
    Decrypt the input data using an RSA private key.

-encrypt
    Encrypt the input data using an RSA public key.

-hexdump
    Hex dump the output data.

-in file
    The input to read from, or standard input if not specified.

-inkey file
    The input key file; by default an RSA private key.

-keyform der | pem
    The private key format. The default is pem.

-oaep | -pkcs | -raw | -x931
    The padding to use: PKCS#1 OAEP, PKCS#1 v1.5 (the default), no padding, or ANSI X9.31, respectively. For signatures, only -pkcs and -raw can be used.

-out file
    The output file to write to, or standard output if not specified.

-passin arg
    The key password source.

-pubin
    The input file is an RSA public key.

-rev
    Reverse the order of the input buffer.

-sign
    Sign the input data and output the signed result. This requires an RSA private key.

-verify
    Verify the input data and output the recovered data.

S_CLIENT

openssl s_client
    [-4 | -6] [-alpn protocols] [-bugs] [-CAfile file] [-CApath directory] [-cert file] [-certform der | pem] [-check_ss_sig] [-cipher cipherlist] [-connect host[:port]] [-crl_check] [-crl_check_all] [-crlf] [-debug] [-dtls] [-dtls1_2] [-extended_crl] [-groups list] [-host host] [-ign_eof] [-ignore_critical] [-issuer_checks] [-key keyfile] [-keyform der | pem] [-keymatexport label] [-keymatexportlen len] [-legacy_server_connect] [-msg] [-mtu mtu] [-nbio] [-nbio_test] [-no_comp] [-no_ign_eof] [-no_legacy_server_connect] [-no_ticket] [-no_tls1_2] [-no_tls1_3] [-pass arg] [-pause] [-policy_check] [-port port] [-prexit] [-proxy host:port] [-quiet] [-reconnect] [-servername name] [-serverpref] [-sess_in file] [-sess_out file] [-showcerts] [-starttls protocol] [-state] [-status] [-timeout] [-tls1_2] [-tls1_3] [-tlsextdebug] [-use_srtp profiles] [-verify depth] [-verify_return_error] [-x509_strict] [-xmpphost host]

The s_client command implements a generic SSL/TLS client which connects to a remote host using SSL/TLS.

If a connection is established with an SSL server, any data received from the server is displayed and any key presses will be sent to the server. When used interactively (which means neither -quiet nor -ign_eof have been given), the session will be renegotiated if the line begins with an R; if the line begins with a Q or if end of file is reached, the connection will be closed down.

The options are as follows:

-4  Attempt connections using IPv4 only.

-6  Attempt connections using IPv6 only.

-alpn protocols
    Enable the Application-Layer Protocol Negotiation. protocols is a comma-separated list of protocol names that the client should advertise support for.

-bugs
    Enable various workarounds for buggy implementations.

-CAfile file
    A file containing trusted certificates to use during server authentication and to use when attempting to build the client certificate chain.

-CApath directory
    The directory to use for server certificate verification. This directory must be in "hash format"; see -verify for more information. These are also used when building the client certificate chain.

-cert file
    The certificate to use, if one is requested by the server. The default is not to use a certificate.

-certform der | pem
    The certificate format. The default is pem.

    -check_ss_sig, -crl_check, -crl_check_all, -extended_crl, -ignore_critical, -issuer_checks, -policy_check, -x509_strict Set various certificate chain validation options. See the verify command for details.

-cipher cipherlist
    Modify the cipher list sent by the client. Although the server determines which cipher suite is used, it should take the first supported cipher in the list sent by the client. See the ciphers command for more information.

-connect host[:port]
    The host and port to connect to. If not specified, an attempt is made to connect to the local host on port 4433. Alternatively, the host and port pair may be separated using a forward-slash character, which is useful for numeric IPv6 addresses.

-crlf
    Translate a line feed from the terminal into CR+LF, as required by some servers.

-debug
    Print extensive debugging information, including a hex dump of all traffic.

-dtls
    Permit any version of DTLS.

-dtls1_2
    Permit only DTLS1.2.

-groups list
    Set the supported elliptic curve groups to the colon separated list of group NIDs or names as documented in SSL_CTX_set1_groups_list(3).

-host host
    The host to connect to. The default is localhost.

-ign_eof
    Inhibit shutting down the connection when end of file is reached in the input.

-key keyfile
    The private key to use. If not specified, the certificate file will be used.

-keyform der | pem
    The private key format. The default is pem.

-keymatexport label
    Export keying material using label.

-keymatexportlen len
    Export len bytes of keying material (default 20).

-legacy_server_connect, -no_legacy_server_connect
    Allow or disallow initial connection to servers that don't support RI.

-msg
    Show all protocol messages with hex dump.

-mtu mtu
    Set the link layer MTU.

-nbio
    Turn on non-blocking I/O.

-nbio_test
    Test non-blocking I/O.

-no_ign_eof
    Shut down the connection when end of file is reached in the input. Can be used to override the implicit -ign_eof after -quiet.

-no_tls1_2 | -no_tls1_3
    Disable the use of TLS1.2 and 1.3, respectively.

-no_ticket
    Disable RFC 4507 session ticket support.

-pass arg
    The private key password source.

-pause
    Pause 1 second between each read and write call.

-port port
    The port to connect to. The default is 4433.

-prexit
    Print session information when the program exits. This will always attempt to print out information even if the connection fails. Normally, information will only be printed out once if the connection succeeds. This option is useful because the cipher in use may be renegotiated or the connection may fail because a client certificate is required or is requested only after an attempt is made to access a certain URL. Note that the output produced by this option is not always accurate because a connection might never have been established.

-proxy host:port
    Use the HTTP proxy at host and port. The connection to the proxy is done in cleartext and the -connect argument is given to the proxy. If not specified, localhost is used as final destination. After that, switch the connection through the proxy to the destination to TLS.

-quiet
    Inhibit printing of session and certificate information. This implicitly turns on -ign_eof as well.

-reconnect
    Reconnect to the same server 5 times using the same session ID; this can be used as a test that session caching is working.

-servername name
    Include the TLS Server Name Indication (SNI) extension in the ClientHello message, using the specified server name.

-showcerts
    Display the whole server certificate chain: normally only the server certificate itself is displayed.

-serverpref
    Use the server's cipher preferences.

-sess_in file
    Load TLS session from file. The client will attempt to resume a connection from this session.

-sess_out file
    Output TLS session to file.

-starttls protocol
    Send the protocol-specific messages to switch to TLS for communication. protocol is a keyword for the intended protocol. Currently, the supported keywords are "ftp", "imap", "smtp", "pop3", and "xmpp".

-state
    Print the SSL session states.

-status
    Send a certificate status request to the server (OCSP stapling). The server response (if any) is printed out.

-timeout
    Enable send/receive timeout on DTLS connections.

-tls1_2 | -tls1_3
    Permit only TLS1.2 or 1.3 respectively.

-tlsextdebug
    Print a hex dump of any TLS extensions received from the server.

-use_srtp profiles
    Offer SRTP key management with a colon-separated profile list.

-verify depth
    Turn on server certificate verification, with a maximum length of depth. Currently the verify operation continues after errors so all the problems with a certificate chain can be seen. As a side effect the connection will never fail due to a server certificate verify failure.

-verify_return_error
    Return verification error.

-xmpphost hostname
    When used with -starttls xmpp, specify the host for the "to" attribute of the stream element. If this option is not specified then the host specified with -connect will be used.

S_SERVER

openssl s_server
    [-accept port] [-alpn protocols] [-bugs] [-CAfile file] [-CApath directory] [-cert file] [-cert2 file] [-certform der | pem] [-cipher cipherlist] [-context id] [-crl_check] [-crl_check_all] [-crlf] [-dcert file] [-dcertform der | pem] [-debug] [-dhparam file] [-dkey file] [-dkeyform der | pem] [-dpass arg] [-dtls] [-dtls1] [-dtls1_2] [-groups list] [-HTTP] [-id_prefix arg] [-key keyfile] [-key2 keyfile] [-keyform der | pem] [-keymatexport label] [-keymatexportlen len] [-msg] [-mtu mtu] [-naccept num] [-named_curve arg] [-nbio] [-nbio_test] [-no_cache] [-no_dhe] [-no_ecdhe] [-no_ticket] [-no_tls1_2] [-no_tls1_3] [-no_tmp_rsa] [-nocert] [-pass arg] [-quiet] [-servername name] [-servername_fatal] [-serverpref] [-state] [-status] [-status_timeout nsec] [-status_url url] [-status_verbose] [-timeout] [-tls1_2] [-tls1_3] [-tlsextdebug] [-use_srtp profiles] [-Verify depth] [-verify depth] [-verify_return_error] [-WWW] [-www]

The s_server command implements a generic SSL/TLS server which listens for connections on a given port using SSL/TLS.

If a connection request is established with a client and neither the -www nor the -WWW option has been used, then any data received from the client is displayed and any key presses are sent to the client. Certain single letter commands perform special operations:

P   Send plain text, which should cause the client to disconnect.
Q   End the current SSL connection and exit.
q   End the current SSL connection, but still accept new connections.
R   Renegotiate the SSL session and request a client certificate.
r   Renegotiate the SSL session.
S   Print out some session cache status information.

The options are as follows:

-accept port
    Listen on TCP port for connections. The default is port 4433.

-alpn protocols
    Enable the Application-Layer Protocol Negotiation. protocols is a comma-separated list of supported protocol names.

-bugs
    Enable various workarounds for buggy implementations.

-CAfile file
    A file containing trusted certificates to use during client authentication and to use when attempting to build the server certificate chain. The list is also used in the list of acceptable client CAs passed to the client when a certificate is requested.

-CApath directory
    The directory to use for client certificate verification. This directory must be in "hash format"; see -verify for more information. These are also used when building the server certificate chain.

-cert file
    The certificate to use: most server's cipher suites require the use of a certificate and some require a certificate with a certain public key type. For example, the DSS cipher suites require a certificate containing a DSS (DSA) key. If not specified, the file server.pem will be used.

-cert2 file
    The certificate to use for servername.

-certform der | pem
    The certificate format. The default is pem.

-cipher cipherlist
    Modify the cipher list used by the server. This allows the cipher list used by the server to be modified. When the client sends a list of supported ciphers, the first client cipher also included in the server list is used. Because the client specifies the preference order, the order of the server cipherlist is irrelevant. See the ciphers command for more information.

-context id
    Set the SSL context ID. It can be given any string value.

-crl_check, -crl_check_all
    Check the peer certificate has not been revoked by its CA. The CRLs are appended to the certificate file. -crl_check_all checks all CRLs of all CAs in the chain.

-crlf
    Translate a line feed from the terminal into CR+LF.

-dcert file, -dkey file
    Specify an additional certificate and private key; these behave in the same manner as the -cert and -key options except there is no default if they are not specified (no additional certificate or key is used). By using RSA and DSS certificates and keys, a server can support clients which only support RSA or DSS cipher suites by using an appropriate certificate.

-dcertform der | pem, -dkeyform der | pem, -dpass arg
    Additional certificate and private key format, and private key password source, respectively.

-debug
    Print extensive debugging information, including a hex dump of all traffic.

-dhparam file
    The DH parameter file to use. The ephemeral DH cipher suites generate keys using a set of DH parameters. If not specified, an attempt is made to load the parameters from the server certificate file. If this fails, a static set of parameters hard coded into the s_server program will be used.

-dtls
    Permit any version of DTLS.

-dtls1_2
    Permit only DTLS1.2.

-groups list
    Set the supported elliptic curve groups to the colon separated list of group NIDs or names as documented in SSL_CTX_set1_groups_list(3).

-HTTP
    Emulate a simple web server. Pages are resolved relative to the current directory. For example if the URL https://myhost/page.html is requested, the file ./page.html will be loaded. The files loaded are assumed to contain a complete and correct HTTP response (lines that are part of the HTTP response line and headers must end with CRLF).

-id_prefix arg
    Generate SSL/TLS session IDs prefixed by arg. This is mostly useful for testing any SSL/TLS code that wish to deal with multiple servers, when each of which might be generating a unique range of session IDs.

-key keyfile
    The private key to use. If not specified, the certificate file will be used.

-key2 keyfile
    The private key to use for servername.

-keyform der | pem
    The private key format. The default is pem.

-keymatexport label
    Export keying material using label.

-keymatexportlen len
    Export len bytes of keying material (default 20).

-msg
    Show all protocol messages with hex dump.

-mtu mtu
    Set the link layer MTU.

-naccept num
    Terminate server after num connections.

-named_curve arg
    Specify the elliptic curve name to use for ephemeral ECDH keys. This option is deprecated; use -groups instead.

-nbio
    Turn on non-blocking I/O.

-nbio_test
    Test non-blocking I/O.

-no_cache
    Disable session caching.

-no_dhe
    Disable ephemeral DH cipher suites.

-no_ecdhe
    Disable ephemeral ECDH cipher suites.

-no_ticket
    Disable RFC 4507 session ticket support.

-no_tls1_2 | -no_tls1_3
    Disable the use of TLS1.2 and 1.3, respectively.

-no_tmp_rsa
    Disable temporary RSA key generation.

-nocert
    Do not use a certificate. This restricts the cipher suites available to the anonymous ones (currently just anonymous DH).

-pass arg
    The private key password source.

-quiet
    Inhibit printing of session and certificate information.

-servername name
    Set the TLS Server Name Indication (SNI) extension with name.

-servername_fatal
    Send fatal alert if servername does not match. The default is warning alert.

-serverpref
    Use server's cipher preferences.

-state
    Print the SSL session states.

-status
    Enables certificate status request support (OCSP stapling).

-status_timeout nsec
    Sets the timeout for OCSP response in seconds.

-status_url url
    Sets a fallback responder URL to use if no responder URL is present in the server certificate. Without this option, an error is returned if the server certificate does not contain a responder address.

-status_verbose
    Enables certificate status request support (OCSP stapling) and gives a verbose printout of the OCSP response.

-timeout
    Enable send/receive timeout on DTLS connections.

-tls1_2 | -tls1_3
    Permit only TLS1.2, or 1.3, respectively.

-tlsextdebug
    Print a hex dump of any TLS extensions received from the server.

-use_srtp profiles
    Offer SRTP key management with a colon-separated profile list.

-verify_return_error
    Return verification error.

-WWW
    Emulate a simple web server. Pages are resolved relative to the current directory. For example if the URL https://myhost/page.html is requested, the file ./page.html will be loaded.

-www
    Send a status message to the client when it connects, including information about the ciphers used and various session parameters. The output is in HTML format so this option will normally be used with a web browser.

-Verify depth, -verify depth
    Request a certificate chain from the client, with a maximum length of depth. With -Verify, the client must supply a certificate or an error occurs; with -verify, a certificate is requested but the client does not have to send one.

S_TIME

openssl s_time
    [-bugs] [-CAfile file] [-CApath directory] [-cert file] [-cipher cipherlist] [-connect host[:port]] [-key keyfile] [-nbio] [-new] [-no_shutdown] [-reuse] [-time seconds] [-verify depth] [-www page]

The s_time command implements a generic SSL/TLS client which connects to a remote host using SSL/TLS. It can request a page from the server and includes the time to transfer the payload data in its timing measurements. It measures the number of connections within a given timeframe, the amount of data transferred (if any), and calculates the average time spent for one connection.

The options are as follows:

-bugs
    Enable various workarounds for buggy implementations.

-CAfile file
    A file containing trusted certificates to use during server authentication and to use when attempting to build the client certificate chain.

-CApath directory
    The directory to use for server certificate verification. This directory must be in "hash format"; see verify for more information. These are also used when building the client certificate chain.

-cert file
    The certificate to use, if one is requested by the server. The default is not to use a certificate.

-cipher cipherlist
    Modify the cipher list sent by the client. Although the server determines which cipher suite is used, it should take the first supported cipher in the list sent by the client. See the ciphers command for more information.

-connect host[:port]
    The host and port to connect to.

-key keyfile
    The private key to use. If not specified, the certificate file will be used.

-nbio
    Turn on non-blocking I/O.

-new
    Perform the timing test using a new session ID for each connection. If neither -new nor -reuse are specified, they are both on by default and executed in sequence.

-no_shutdown
    Shut down the connection without sending a "close notify" shutdown alert to the server.

-reuse
    Perform the timing test using the same session ID for each connection. If neither -new nor -reuse are specified, they are both on by default and executed in sequence.

-time seconds
    Limit s_time benchmarks to the number of seconds. The default is 30 seconds.

-verify depth
    Turn on server certificate verification, with a maximum length of depth. Currently the verify operation continues after errors, so all the problems with a certificate chain can be seen. As a side effect, the connection will never fail due to a server certificate verify failure.

-www page
    The page to GET from the server. A value of ‘/’ gets the index.htm[l] page. If this parameter is not specified, s_time will only perform the handshake to establish SSL connections but not transfer any payload data.

SESS_ID

openssl sess_id
    [-cert] [-context ID] [-in file] [-inform der | pem] [-noout] [-out file] [-outform der | pem] [-text]

The sess_id program processes the encoded version of the SSL session structure and optionally prints out SSL session details (for example the SSL session master key) in human-readable format.

The options are as follows:

-cert
    If a certificate is present in the session, it will be output using this option; if the -text option is also present, then it will be printed out in text form.

-context ID
    Set the session ID. The ID can be any string of characters.

-in file
    The input file to read from, or standard input if not specified.

-inform der | pem
    The input format. der uses an ASN.1 DER-encoded format containing session details. The precise format can vary from one version to the next. pem is the default format: it consists of the DER format base64-encoded with additional header and footer lines.

-noout
    Do not output the encoded version of the session.

-out file
    The output file to write to, or standard output if not specified.

-outform der | pem
    The output format.

-text
    Print the various public or private key components in plain text, in addition to the encoded version.

The output of sess_id is composed as follows:

Protocol
    The protocol in use.
Cipher
    The actual raw SSL or TLS cipher code.
Session-ID
    The SSL session ID, in hex format.
Session-ID-ctx
    The session ID context, in hex format.
Master-Key
    The SSL session master key.
Key-Arg
    The key argument; this is only used in SSL v2.
Start Time
    The session start time. UNIX format.
Timeout
    The timeout, in seconds.
Verify return code
    The return code when a certificate is verified.

Since the SSL session output contains the master key, it is possible to read the contents of an encrypted session using this information. Therefore appropriate security precautions should be taken if the information is being output by a "real" application. This is, however, strongly discouraged and should only be used for debugging purposes.

SMIME

openssl smime
    [ -aes128 | -aes192 | -aes256 | -des | -des3 | -rc2-40 | -rc2-64 | -rc2-128] [-binary] [-CAfile file] [-CApath directory] [-certfile file] [-check_ss_sig] [-content file] [-crl_check] [-crl_check_all] [-decrypt] [-encrypt] [-extended_crl] [-from addr] [-ignore_critical] [-in file] [-indef] [-inform der | pem | smime] [-inkey file] [-issuer_checks] [-keyform der | pem] [-md digest] [-noattr] [-nocerts] [-nochain] [-nodetach] [-noindef] [-nointern] [-nosigs] [-nosmimecap] [-noverify] [-out file] [-outform der | pem | smime] [-passin arg] [-pk7out] [-policy_check] [-recip file] [-resign] [-sign] [-signer file] [-stream] [-subject s] [-text] [-to addr] [-verify] [-x509_strict] [cert.pem ...]

The smime command handles S/MIME mail. It can encrypt, decrypt, sign, and verify S/MIME messages.

The MIME message must be sent without any blank lines between the headers and the output. Some mail programs will automatically add a blank line. Piping the mail directly to an MTA is one way to achieve the correct format.

The supplied message to be signed or encrypted must include the necessary MIME headers or many S/MIME clients won't display it properly (if at all). Use the -text option to automatically add plain text headers.

A "signed and encrypted" message is one where a signed message is then encrypted. This can be produced by encrypting an already signed message.

There are a number of operations that can be performed, as follows:

-decrypt
    Decrypt mail using the supplied certificate and private key. The input file is an encrypted mail message in MIME format. The decrypted mail is written to the output file.

-encrypt
    Encrypt mail for the given recipient certificates. The input is the message to be encrypted. The output file is the encrypted mail, in MIME format.

-pk7out
    Take an input message and write out a PEM-encoded PKCS#7 structure.

-resign
    Resign a message: take an existing message and one or more new signers.

-sign
    Sign mail using the supplied certificate and private key. The input file is the message to be signed. The signed message, in MIME format, is written to the output file.

-verify
    Verify signed mail. The input is a signed mail message and the output is the signed data. Both clear text and opaque signing is supported.

The remaining options are as follows:

    -aes128 | -aes192 | -aes256 | -des | -des3 | -rc2-40 | -rc2-64 | -rc2-128 The encryption algorithm to use. 128-, 192-, or 256-bit AES, DES (56 bits), triple DES (168 bits), or 40-, 64-, or 128-bit RC2, respectively; if not specified, 40-bit RC2 is used. Only used with -encrypt.

-binary
    Normally, the input message is converted to "canonical" format which uses CR/LF as end of line, as required by the S/MIME specification. When this option is present, no translation occurs. This is useful when handling binary data which may not be in MIME format.

-CAfile file
    A file containing trusted CA certificates; only used with -verify.

-CApath directory
    A directory containing trusted CA certificates; only used with -verify. This directory must be a standard certificate directory: that is, a hash of each subject name (using x509 -hash) should be linked to each certificate.

cert.pem ...
    One or more certificates of message recipients: used when encrypting a message.

-certfile file
    Allows additional certificates to be specified. When signing, these will be included with the message. When verifying, these will be searched for the signers' certificates. The certificates should be in PEM format.

    -check_ss_sig, -crl_check, -crl_check_all, -extended_crl, -ignore_critical, -issuer_checks, -policy_check, -x509_strict Set various certificate chain validation options. See the verify command for details.

-content file
    A file containing the detached content. This is only useful with the -verify option, and only usable if the PKCS#7 structure is using the detached signature form where the content is not included. This option will override any content if the input format is S/MIME and it uses the multipart/signed MIME content type.

    -from addr, -subject s, -to addr The relevant mail headers. These are included outside the signed portion of a message so they may be included manually. When signing, many S/MIME mail clients check that the signer's certificate email address matches the From: address.

-in file
    The input file to read from.

-indef
    Enable streaming I/O for encoding operations. This permits single pass processing of data without the need to hold the entire contents in memory, potentially supporting very large files. Streaming is automatically set for S/MIME signing with detached data if the output format is SMIME; it is currently off by default for all other operations.

-inform der | pem | smime
    The input format.

-inkey file
    The private key to use when signing or decrypting, which must match the corresponding certificate. If this option is not specified, the private key must be included in the certificate file specified with the -recip or -signer file. When signing, this option can be used multiple times to specify successive keys.

-keyform der | pem
    Input private key format. The default is pem.

-md digest
    The digest algorithm to use when signing or resigning. If not present then the default digest algorithm for the signing key is used (usually SHA1).

-noattr
    Do not include attributes.

-nocerts
    Do not include the signer's certificate. This will reduce the size of the signed message but the verifier must have a copy of the signer's certificate available locally (passed using the -certfile option, for example).

-nochain
    Do not do chain verification of signers' certificates: that is, don't use the certificates in the signed message as untrusted CAs.

-nodetach
    When signing a message, use opaque signing: this form is more resistant to translation by mail relays but it cannot be read by mail agents that do not support S/MIME. Without this option cleartext signing with the MIME type multipart/signed is used.

-noindef
    Disable streaming I/O where it would produce an encoding of indefinite length (currently has no effect).

-nointern
    Only use certificates specified in the -certfile. The supplied certificates can still be used as untrusted CAs.

-nosigs
    Do not try to verify the signatures on the message.

-nosmimecap
    Exclude the list of supported algorithms from signed attributes, other options such as signing time and content type are still included.

-noverify
    Do not verify the signer's certificate of a signed message.

-out file
    The output file to write to.

-outform der | pem | smime
    The output format. The default is smime, which writes an S/MIME format message. pem and der change this to write PEM and DER format PKCS#7 structures instead. This currently only affects the output format of the PKCS#7 structure; if no PKCS#7 structure is being output (for example with -verify or -decrypt) this option has no effect.

-passin arg
    The key password source.

-recip file
    The recipients certificate when decrypting a message. This certificate must match one of the recipients of the message or an error occurs.

-signer file
    A signing certificate when signing or resigning a message; this option can be used multiple times if more than one signer is required. If a message is being verified, the signer's certificates will be written to this file if the verification was successful.

-stream
    The same as -indef.

-text
    Add plain text (text/plain) MIME headers to the supplied message if encrypting or signing. If decrypting or verifying, it strips off text headers: if the decrypted or verified message is not of MIME type text/plain then an error occurs.

The exit codes for smime are as follows:

0   The operation was completely successful.
1   An error occurred parsing the command options.
2   One of the input files could not be read.
3   An error occurred creating the file or when reading the message.
4   An error occurred decrypting or verifying the message.
5   An error occurred writing certificates.

SPEED

openssl speed
    [algorithm] [-decrypt] [-elapsed] [-evp algorithm] [-mr] [-multi number] [-unaligned number]

The speed command is used to test the performance of cryptographic algorithms.

algorithm
    Perform the test using algorithm. The default is to test all algorithms.

-decrypt
    Time decryption instead of encryption; must be used with -evp.

-elapsed
    Measure time in real time instead of CPU user time.

-evp algorithm
    Perform the test using one of the algorithms accepted by EVP_get_cipherbyname(3).

-mr Produce machine readable output.

-multi number
    Run number benchmarks in parallel.

-unaligned number
    Use allocated buffers with an offset of number bytes from the alignment provided by malloc(3). number should be between 0 and 16.

SPKAC

openssl spkac
    [-challenge string] [-in file] [-key keyfile] [-noout] [-out file] [-passin arg] [-pubkey] [-spkac spkacname] [-spksect section] [-verify]

The spkac command processes signed public key and challenge (SPKAC) files. It can print out their contents, verify the signature, and produce its own SPKACs from a supplied private key.

The options are as follows:

-challenge string
    The challenge string, if an SPKAC is being created.

-in file
    The input file to read from, or standard input if not specified. Ignored if the -key option is used.

-key keyfile
    Create an SPKAC file using the private key in keyfile. The -in, -noout, -spksect, and -verify options are ignored, if present.

-noout
    Do not output the text version of the SPKAC.

-out file
    The output file to write to, or standard output if not specified.

-passin arg
    The key password source.

-pubkey
    Output the public key of an SPKAC.

-spkac spkacname
    An alternative name for the variable containing the SPKAC. The default is "SPKAC". This option affects both generated and input SPKAC files.

-spksect section
    An alternative name for the section containing the SPKAC.

-verify
    Verify the digital signature on the supplied SPKAC.

TS

openssl ts
    -query [-md4 | -md5 | -ripemd160 | -sha1] [-cert] [-config configfile] [-data file_to_hash] [-digest digest_bytes] [-in request.tsq] [-no_nonce] [-out request.tsq] [-policy object_id] [-text]

openssl ts
    -reply [-chain certs_file.pem] [-config configfile] [-in response.tsr] [-inkey private.pem] [-out response.tsr] [-passin arg] [-policy object_id] [-queryfile request.tsq] [-section tsa_section] [-signer tsa_cert.pem] [-text] [-token_in] [-token_out]

openssl ts
    -verify [-CAfile trusted_certs.pem] [-CApath trusted_cert_path] [-data file_to_hash] [-digest digest_bytes] [-in response.tsr] [-queryfile request.tsq] [-token_in] [-untrusted cert_file.pem]

The ts command is a basic Time Stamping Authority (TSA) client and server application as specified in RFC 3161 (Time-Stamp Protocol, TSP). A TSA can be part of a PKI deployment and its role is to provide long term proof of the existence of specific data. Here is a brief description of the protocol:

1.  The TSA client computes a one-way hash value for a data file and sends the hash to the TSA.

2.  The TSA attaches the current date and time to the received hash value, signs them and sends the time stamp token back to the client. By creating this token the TSA certifies the existence of the original data file at the time of response generation.

3.  The TSA client receives the time stamp token and verifies the signature on it. It also checks if the token contains the same hash value that it had sent to the TSA.

There is one DER-encoded protocol data unit defined for transporting a time stamp request to the TSA and one for sending the time stamp response back to the client. The ts command has three main functions: creating a time stamp request based on a data file; creating a time stamp response based on a request; and verifying if a response corresponds to a particular request or a data file.

There is no support for sending the requests/responses automatically over HTTP or TCP yet as suggested in RFC 3161. Users must send the requests either by FTP or email.

The -query switch can be used for creating and printing a time stamp request with the following options:

-cert
    Expect the TSA to include its signing certificate in the response.

-config configfile
    Specify an alternative configuration file. Only the OID section is used.

-data file_to_hash
    The data file for which the time stamp request needs to be created. The default is standard input.

-digest digest_bytes
    Specify the message imprint explicitly without the data file. The imprint must be specified in a hexadecimal format, two characters per byte, the bytes optionally separated by colons. The number of bytes must match the message digest algorithm in use.

-in request.tsq
    A previously created time stamp request in DER format that will be printed into the output file. Useful for examining the content of a request in human-readable format.

-md4 | -md5 | -ripemd160 | -sha | -sha1
    The message digest to apply to the data file. It supports all the message digest algorithms that are supported by the dgst command. The default is SHA1.

-no_nonce
    Specify no nonce in the request. The default, to include a 64-bit long pseudo-random nonce, is recommended to protect against replay attacks.

-out request.tsq
    The output file to write to, or standard output if not specified.

-policy object_id
    The policy that the client expects the TSA to use for creating the time stamp token. Either dotted OID notation or OID names defined in the config file can be used. If no policy is requested, the TSA uses its own default policy.

-text
    Output in human-readable text format instead of DER.

A time stamp response (TimeStampResp) consists of a response status and the time stamp token itself (ContentInfo), if the token generation was successful. The -reply command is for creating a time stamp response or time stamp token based on a request and printing the response/token in human-readable format. If -token_out is not specified the output is always a time stamp response (TimeStampResp), otherwise it is a time stamp token (ContentInfo).

-chain certs_file.pem
    The collection of PEM certificates that will be included in the response in addition to the signer certificate if the -cert option was used for the request. This file is supposed to contain the certificate chain for the signer certificate from its issuer upwards. The -reply command does not build a certificate chain automatically.

-config configfile
    Specify an alternative configuration file.

-in response.tsr
    Specify a previously created time stamp response (or time stamp token, if -token_in is also specified) in DER format that will be written to the output file. This option does not require a request; it is useful, for example, to examine the content of a response or token or to extract the time stamp token from a response. If the input is a token and the output is a time stamp response, a default "granted" status info is added to the token.

-inkey private.pem
    The signer private key of the TSA in PEM format. Overrides the signer_key config file option.

-out response.tsr
    The response is written to this file. The format and content of the file depends on other options (see -text and -token_out). The default is stdout.

-passin arg
    The key password source.

-policy object_id
    The default policy to use for the response. Either dotted OID notation or OID names defined in the config file can be used. If no policy is requested, the TSA uses its own default policy.

-queryfile request.tsq
    The file containing a DER-encoded time stamp request.

-section tsa_section
    The config file section containing the settings for response generation.

-signer tsa_cert.pem
    The PEM signer certificate of the TSA. The TSA signing certificate must have exactly one extended key usage assigned to it: timeStamping. The extended key usage must also be critical, otherwise the certificate is going to be refused. Overrides the signer_cert variable of the config file.

-text
    Output in human-readable text format instead of DER.

-token_in
    The input is a DER-encoded time stamp token (ContentInfo) instead of a time stamp response (TimeStampResp).

-token_out
    The output is a time stamp token (ContentInfo) instead of a time stamp response (TimeStampResp).

The -verify command is for verifying if a time stamp response or time stamp token is valid and matches a particular time stamp request or data file. The -verify command does not use the configuration file.

-CAfile trusted_certs.pem
    The file containing a set of trusted self-signed PEM CA certificates. See verify for additional details. Either this option or -CApath must be specified.

-CApath trusted_cert_path
    The directory containing the trusted CA certificates of the client. See verify for additional details. Either this option or -CAfile must be specified.

-data file_to_hash
    The response or token must be verified against file_to_hash. The file is hashed with the message digest algorithm specified in the token. The -digest and -queryfile options must not be specified with this one.

-digest digest_bytes
    The response or token must be verified against the message digest specified with this option. The number of bytes must match the message digest algorithm specified in the token. The -data and -queryfile options must not be specified with this one.

-in response.tsr
    The time stamp response that needs to be verified, in DER format. This option in mandatory.

-queryfile request.tsq
    The original time stamp request, in DER format. The -data and -digest options must not be specified with this one.

-token_in
    The input is a DER-encoded time stamp token (ContentInfo) instead of a time stamp response (TimeStampResp).

-untrusted cert_file.pem
    Additional untrusted PEM certificates which may be needed when building the certificate chain for the TSA's signing certificate. This file must contain the TSA signing certificate and all intermediate CA certificates unless the response includes them.

Options specified on the command line always override the settings in the config file:

tsa section, default_tsa
    This is the main section and it specifies the name of another section that contains all the options for the -reply option. This section can be overridden with the -section command line switch.

oid_file
    See ca for a description.

oid_section
    See ca for a description.

serial
    The file containing the hexadecimal serial number of the last time stamp response created. This number is incremented by 1 for each response. If the file does not exist at the time of response generation, a new file is created with serial number 1. This parameter is mandatory.

signer_cert
    TSA signing certificate, in PEM format. The same as the -signer command line option.

certs
    A set of PEM-encoded certificates that need to be included in the response. The same as the -chain command line option.

signer_key
    The private key of the TSA, in PEM format. The same as the -inkey command line option.

default_policy
    The default policy to use when the request does not mandate any policy. The same as the -policy command line option.

other_policies
    Comma separated list of policies that are also acceptable by the TSA and used only if the request explicitly specifies one of them.

digests
    The list of message digest algorithms that the TSA accepts. At least one algorithm must be specified. This parameter is mandatory.

accuracy
    The accuracy of the time source of the TSA in seconds, milliseconds and microseconds. For example, secs:1, millisecs:500, microsecs:100. If any of the components is missing, zero is assumed for that field.

clock_precision_digits
    The maximum number of digits, which represent the fraction of seconds, that need to be included in the time field. The trailing zeroes must be removed from the time, so there might actually be fewer digits or no fraction of seconds at all. The maximum value is 6; the default is 0.

ordering
    If this option is yes, the responses generated by this TSA can always be ordered, even if the time difference between two responses is less than the sum of their accuracies. The default is no.

tsa_name
    Set this option to yes if the subject name of the TSA must be included in the TSA name field of the response. The default is no.

ess_cert_id_chain
    The SignedData objects created by the TSA always contain the certificate identifier of the signing certificate in a signed attribute (see RFC 2634, Enhanced Security Services). If this option is set to yes and either the certs variable or the -chain option is specified then the certificate identifiers of the chain will also be included in the SigningCertificate signed attribute. If this variable is set to no, only the signing certificate identifier is included. The default is no.

VERIFY

openssl verify
    [-CAfile file] [-CApath directory] [-check_ss_sig] [-CRLfile file] [-crl_check] [-crl_check_all] [-explicit_policy] [-extended_crl] [-help] [-ignore_critical] [-inhibit_any] [-inhibit_map] [-issuer_checks] [-legacy_verify] [-policy_check] [-purpose purpose] [-trusted file] [-untrusted file] [-verbose] [-x509_strict] [certificates]

The verify command verifies certificate chains.

The options are as follows:

-CAfile file
    A file of trusted certificates. The file should contain multiple certificates in PEM format, concatenated together.

-CApath directory
    A directory of trusted certificates. The certificates, or symbolic links to them, should have names of the form hash.0, where hash is the hashed certificate subject name (see the -hash option of the x509 utility).

-check_ss_sig
    Verify the signature on the self-signed root CA. This is disabled by default because it doesn't add any security.

-CRLfile file
    The file should contain one or more CRLs in PEM format.

-crl_check
    Check end entity certificate validity by attempting to look up a valid CRL. If a valid CRL cannot be found, an error occurs.

-crl_check_all
    Check the validity of all certificates in the chain by attempting to look up valid CRLs.

-explicit_policy
    Set policy variable require-explicit-policy (RFC 3280).

-extended_crl
    Enable extended CRL features such as indirect CRLs and alternate CRL signing keys.

-help
    Print a usage message.

-ignore_critical
    Ignore critical extensions instead of rejecting the certificate.

-inhibit_any
    Set policy variable inhibit-any-policy (RFC 3280).

-inhibit_map
    Set policy variable inhibit-policy-mapping (RFC 3280).

-issuer_checks
    Print diagnostics relating to searches for the issuer certificate of the current certificate showing why each candidate issuer certificate was rejected. The presence of rejection messages does not itself imply that anything is wrong: during the normal verify process several rejections may take place.

-legacy_verify
    Use the legacy X.509 certificate chain verification code.

-policy_check
    Enable certificate policy processing.

-purpose purpose
    The intended use for the certificate. Without this option no chain verification will be done. Currently accepted uses are sslclient, sslserver, nssslserver, smimesign, smimeencrypt, crlsign, any, and ocsphelper.

-trusted file
    A file of trusted certificates. The file should contain multiple certificates.

-untrusted file
    A file of untrusted certificates. The file should contain multiple certificates.

-verbose
    Print extra information about the operations being performed.

-x509_strict
    Disable workarounds for broken certificates which have to be disabled for strict X.509 compliance.

certificates
    One or more PEM certificates to verify. If no certificate files are included, an attempt is made to read a certificate from standard input. If the first certificate filename begins with a dash, use a lone dash to mark the last option.

The verify program uses the same functions as the internal SSL and S/MIME verification, with one crucial difference: wherever possible an attempt is made to continue after an error, whereas normally the verify operation would halt on the first error. This allows all the problems with a certificate chain to be determined.

The verify operation consists of a number of separate steps. Firstly a certificate chain is built up starting from the supplied certificate and ending in the root CA. It is an error if the whole chain cannot be built up. The chain is built up by looking up the issuer's certificate of the current certificate. If a certificate is found which is its own issuer, it is assumed to be the root CA.

All certificates whose subject name matches the issuer name of the current certificate are subject to further tests. The relevant authority key identifier components of the current certificate (if present) must match the subject key identifier (if present) and issuer and serial number of the candidate issuer; in addition the keyUsage extension of the candidate issuer (if present) must permit certificate signing.

The lookup first looks in the list of untrusted certificates and if no match is found the remaining lookups are from the trusted certificates. The root CA is always looked up in the trusted certificate list: if the certificate to verify is a root certificate, then an exact match must be found in the trusted list.

The second operation is to check every untrusted certificate's extensions for consistency with the supplied purpose. If the -purpose option is not included, then no checks are done. The supplied or "leaf" certificate must have extensions compatible with the supplied purpose and all other certificates must also be valid CA certificates. The precise extensions required are described in more detail in the X509 section below.

The third operation is to check the trust settings on the root CA. The root CA should be trusted for the supplied purpose. A certificate with no trust settings is considered to be valid for all purposes.

The final operation is to check the validity of the certificate chain. The validity period is checked against the current system time and the notBefore and notAfter dates in the certificate. The certificate signatures are also checked at this point.

If all operations complete successfully, the certificate is considered valid. If any operation fails then the certificate is not valid. When a verify operation fails, the output messages can be somewhat cryptic. The general form of the error message is:

    server.pem: /C=AU/ST=Queensland/O=CryptSoft Pty Ltd/CN=Test CA (1024-bit)
    error 24 at 1 depth lookup:invalid CA certificate

The first line contains the name of the certificate being verified, followed by the subject name of the certificate. The second line contains the error number as defined by the X509_V_ERR_* constants in <openssl/x509_vfy.h>, the associated error message documented in X509_STORE_CTX_get_error(3), and the depth. The depth is the number of the certificate being verified when a problem was detected starting with zero for the certificate being verified itself, then 1 for the CA that signed the certificate and so on.

VERSION
openssl version [-abdfopv]

The version command is used to print out version information about openssl.

The options are as follows:

-a  All information: this is the same as setting all the other flags.

-b  The date the current version of openssl was built.

-d  OPENSSLDIR setting.

-f  Compilation flags.

-o  Option information: various options set when the library was built.

-p  Platform setting.

-v  The current openssl version.

X509

openssl x509
    [-C] [-addreject arg] [-addtrust arg] [-alias] [-CA file] [-CAcreateserial] [-CAform der | pem] [-CAkey file] [-CAkeyform der | pem] [-CAserial file] [-certopt option] [-checkend arg] [-clrext] [-clrreject] [-clrtrust] [-dates] [-days arg] [-email] [-enddate] [-extensions section] [-extfile file] [-fingerprint] [-hash] [-in file] [-inform der | net | pem] [-issuer] [-issuer_hash] [-issuer_hash_old] [-keyform der | pem] [-md5 | -sha1] [-modulus] [-nameopt option] [-next_serial] [-noout] [-ocsp_uri] [-ocspid] [-out file] [-outform der | net | pem] [-passin arg] [-pubkey] [-purpose] [-req] [-serial] [-set_serial n] [-setalias arg] [-signkey file] [-sigopt nm:v] [-startdate] [-subject] [-subject_hash] [-subject_hash_old] [-text] [-trustout] [-x509toreq]

The x509 command is a multi-purpose certificate utility. It can be used to display certificate information, convert certificates to various forms, sign certificate requests like a "mini CA", or edit certificate trust settings.

The following are x509 input, output, and general purpose options:

-in file
    The input file to read from, or standard input if not specified.

-inform der | net | pem
    The input format. Normally, the command will expect an X.509 certificate, but this can change if other options such as -req are present.

-md5 | -sha1
    The digest to use. This affects any signing or display option that uses a message digest, such as the -fingerprint, -signkey, and -CA options. If not specified, MD5 is used. SHA1 is always used with DSA keys.

-out file
    The output file to write to, or standard output if none is specified.

-outform der | net | pem
    The output format.

-passin arg
    The key password source.

The following are x509 display options:

-C  Output the certificate in the form of a C source file.

-certopt option
    Customise the output format used with -text, either using a list of comma-separated options or by specifying -certopt multiple times. The default behaviour is to print all fields. The options are as follows:

    ca_default
        Equivalent to no_issuer, no_pubkey, no_header, no_version, no_sigdump, and no_signame.
    compatible
        Equivalent to no output options at all.
    ext_default
        Print unsupported certificate extensions.
    ext_dump
        Hex dump unsupported extensions.
    ext_error
        Print an error message for unsupported certificate extensions.
    ext_parse
        ASN.1 parse unsupported extensions.
    no_aux
        Do not print certificate trust information.
    no_extensions
        Do not print X509V3 extensions.
    no_header
        Do not print header (Certificate and Data) information.
    no_issuer
        Do not print the issuer name.
    no_pubkey
        Do not print the public key.
    no_serial
        Do not print the serial number.
    no_sigdump
        Do not give a hexadecimal dump of the certificate signature.
    no_signame
        Do not print the signature algorithm used.
    no_subject
        Do not print the subject name.
    no_validity
        Do not print the notBefore and notAfter (validity) fields.
    no_version
        Do not print the version number.

-dates
    Print the start and expiry date of a certificate.

-email
    Output the email addresses, if any.

-enddate
    Print the expiry date of the certificate; that is, the notAfter date.

-fingerprint
    Print the digest of the DER-encoded version of the whole certificate.

-hash
    A synonym for -subject_hash.

-issuer
    Print the issuer name.

-issuer_hash
    Print the hash of the certificate issuer name.

-issuer_hash_old
    Print the hash of the certificate issuer name using the older algorithm as used by openssl versions before 1.0.0.

-modulus
    Print the value of the modulus of the public key contained in the certificate.

-nameopt option
    Customise how the subject or issuer names are displayed, either using a list of comma-separated options or by specifying -nameopt multiple times. The default behaviour is to use the oneline format. The options, which can be preceded by a dash to turn them off, are as follows:

    align
        Align field values for a more readable output. Only usable with sep_multiline.

    compat
        Use the old format, equivalent to specifying no options at all.

    dn_rev
        Reverse the fields of the DN, as required by RFC 2253. As a side effect, this also reverses the order of multiple AVAs.

    dump_all
        Dump all fields. When used with dump_der, it allows the DER encoding of the structure to be unambiguously determined.

    dump_der
        Any fields that need to be hexdumped are dumped using the DER encoding of the field. Otherwise just the content octets will be displayed. Both options use the RFC 2253 #XXXX... format.

    dump_nostr
        Dump non-character string types (for example OCTET STRING); usually, non-character string types are displayed as though each content octet represents a single character.

    dump_unknown
        Dump any field whose OID is not recognised by openssl.

    esc_2253
        Escape the "special" characters required by RFC 2253 in a field that is “,+"<>;”. Additionally, ‘#’ is escaped at the beginning of a string and a space character at the beginning or end of a string.

    esc_ctrl
        Escape control characters. That is, those with ASCII values less than 0x20 (space) and the delete (0x7f) character. They are escaped using the RFC 2253 \XX notation (where XX are two hex digits representing the character value).

    esc_msb
        Escape characters with the MSB set; that is, with ASCII values larger than 127.

    multiline
        A multiline format. Equivalent to esc_ctrl, esc_msb, sep_multiline, space_eq, lname, and align.

    no_type
        Do not attempt to interpret multibyte characters. That is, content octets are merely dumped as though one octet represents each character. This is useful for diagnostic purposes but results in rather odd looking output.

    nofname, sname, lname, oid
        Alter how the field name is displayed: nofname does not display the field at all; sname uses the short name form (CN for commonName, for example); lname uses the long form. oid represents the OID in numerical form and is useful for diagnostic purpose.

    oneline
        A one line format which is more readable than RFC2253. Equivalent to esc_2253, esc_ctrl, esc_msb, utf8, dump_nostr, dump_der, use_quote, sep_comma_plus_spc, space_eq, and sname.

    RFC2253
        Displays names compatible with RFC 2253. Equivalent to esc_2253, esc_ctrl, esc_msb, utf8, dump_nostr, dump_unknown, dump_der, sep_comma_plus, dn_rev, and sname.

    sep_comma_plus, sep_comma_plus_space, sep_semi_plus_space, sep_multiline
        Determine the field separators: the first character is between RDNs and the second between multiple AVAs (multiple AVAs are very rare and their use is discouraged). The options ending in "space" additionally place a space after the separator to make it more readable. sep_multiline uses a linefeed character for the RDN separator and a spaced ‘+’ for the AVA separator, as well as indenting the fields by four characters. If no field separator is specified then sep_comma_plus_space is used by default.

    show_type
        Show the type of the ASN.1 character string. The type precedes the field contents. For example "BMPSTRING: Hello World".

    space_eq
        Place spaces round the ‘=’ character which follows the field name.

    use_quote
        Escape some characters by surrounding the whole string with ‘"’ characters. Without the option, all escaping is done with the ‘\’ character.

    utf8
        Convert all strings to UTF8 format first, as required by RFC 2253. On a UTF8 compatible terminal, the use of this option (and not setting esc_msb) may result in the correct display of multibyte characters. Usually, multibyte characters larger than 0xff are represented using the format \UXXXX for 16 bits and \WXXXXXXXX for 32 bits, and any UTF8Strings are converted to their character form first.

-next_serial
    Print the next serial number.

-noout
    Do not output the encoded version of the request.

-ocsp_uri
    Print the OCSP responder addresses, if any.

-ocspid
    Print OCSP hash values for the subject name and public key.

-pubkey
    Print the public key.

-serial
    Print the certificate serial number.

-sigopt nm:v
    Pass options to the signature algorithm during sign or certify operations. The names and values of these options are algorithm-specific.

-startdate
    Print the start date of the certificate; that is, the notBefore date.

-subject
    Print the subject name.

-subject_hash
    Print the hash of the certificate subject name. This is used in openssl to form an index to allow certificates in a directory to be looked up by subject name.

-subject_hash_old
    Print the hash of the certificate subject name using the older algorithm as used by openssl versions before 1.0.0.

-text
    Print the full certificate in text form.

A trusted certificate is a certificate which has several additional pieces of information attached to it such as the permitted and prohibited uses of the certificate and an alias. When a certificate is being verified, at least one certificate must be trusted. By default, a trusted certificate must be stored locally and be a root CA. The following are x509 trust settings options:

-addreject arg
    Add a prohibited use. Accepts the same values as the -addtrust option.

-addtrust arg
    Add a trusted certificate use. Any object name can be used here, but currently only clientAuth (SSL client use), serverAuth (SSL server use), and emailProtection (S/MIME email) are used.

-alias
    Output the certificate alias.

-clrreject
    Clear all the prohibited or rejected uses of the certificate.

-clrtrust
    Clear all the permitted or trusted uses of the certificate.

-purpose
    Perform tests on the certificate extensions. The same code is used when verifying untrusted certificates in chains, so this section is useful if a chain is rejected by the verify code.

    The basicConstraints extension CA flag is used to determine whether the certificate can be used as a CA. If the CA flag is true, it is a CA; if the CA flag is false, it is not a CA. All CAs should have the CA flag set to true.

    If the basicConstraints extension is absent, then the certificate is considered to be a possible CA; other extensions are checked according to the intended use of the certificate. A warning is given in this case because the certificate should really not be regarded as a CA. However it is allowed to be a CA to work around some broken software.

    If the certificate is a V1 certificate (and thus has no extensions) and it is self-signed, it is also assumed to be a CA but a warning is again given. This is to work around the problem of Verisign roots which are V1 self-signed certificates.

    If the keyUsage extension is present, then additional restraints are made on the uses of the certificate. A CA certificate must have the keyCertSign bit set if the keyUsage extension is present.

    The extended key usage extension places additional restrictions on the certificate uses. If this extension is present, whether critical or not, the key can only be used for the purposes specified.

    A complete description of each test is given below. The comments about basicConstraints and keyUsage and V1 certificates above apply to all CA certificates.

    SSL Client
        The extended key usage extension must be absent or include the web client authentication OID. keyUsage must be absent or it must have the digitalSignature bit set. The Netscape certificate type must be absent or it must have the SSL client bit set.

    SSL Client CA
        The extended key usage extension must be absent or include the web client authentication OID. The Netscape certificate type must be absent or it must have the SSL CA bit set: this is used as a workaround if the basicConstraints extension is absent.

    SSL Server
        The extended key usage extension must be absent or include the web server authentication and/or one of the SGC OIDs. keyUsage must be absent or it must have the digitalSignature set, the keyEncipherment set, or both bits set. The Netscape certificate type must be absent or have the SSL server bit set.

    SSL Server CA
        The extended key usage extension must be absent or include the web server authentication and/or one of the SGC OIDs. The Netscape certificate type must be absent or the SSL CA bit must be set: this is used as a workaround if the basicConstraints extension is absent.

    Netscape SSL Server
        For Netscape SSL clients to connect to an SSL server; it must have the keyEncipherment bit set if the keyUsage extension is present. This isn't always valid because some cipher suites use the key for digital signing. Otherwise it is the same as a normal SSL server.

    Common S/MIME Client Tests
        The extended key usage extension must be absent or include the email protection OID. The Netscape certificate type must be absent or should have the S/MIME bit set. If the S/MIME bit is not set in Netscape certificate type, then the SSL client bit is tolerated as an alternative but a warning is shown: this is because some Verisign certificates don't set the S/MIME bit.

    S/MIME Signing
        In addition to the common S/MIME client tests, the digitalSignature bit must be set if the keyUsage extension is present.

    S/MIME Encryption
        In addition to the common S/MIME tests, the keyEncipherment bit must be set if the keyUsage extension is present.

    S/MIME CA
        The extended key usage extension must be absent or include the email protection OID. The Netscape certificate type must be absent or must have the S/MIME CA bit set: this is used as a workaround if the basicConstraints extension is absent.

    CRL Signing
        The keyUsage extension must be absent or it must have the CRL signing bit set.

    CRL Signing CA
        The normal CA tests apply, except the basicConstraints extension must be present.

-setalias arg
    Set the alias of the certificate, allowing the certificate to be referred to using a nickname, such as "Steve's Certificate".

-trustout
    Output a trusted certificate (the default if any trust settings are modified). An ordinary or trusted certificate can be input, but by default an ordinary certificate is output and any trust settings are discarded.

The x509 utility can be used to sign certificates and requests: it can thus behave like a mini CA. The following are x509 signing options:

-CA file
    The CA certificate to be used for signing. When this option is present, x509 behaves like a mini CA. The input file is signed by the CA using this option; that is, its issuer name is set to the subject name of the CA and it is digitally signed using the CA's private key.

    This option is normally combined with the -req option. Without the -req option, the input is a certificate which must be self-signed.

-CAcreateserial
    Create the CA serial number file if it does not exist instead of generating an error. The file will contain the serial number ‘02’ and the certificate being signed will have ‘1’ as its serial number.

-CAform der | pem
    The format of the CA certificate file. The default is pem.

-CAkey file
    Set the CA private key to sign a certificate with. Otherwise it is assumed that the CA private key is present in the CA certificate file.

-CAkeyform der | pem
    The format of the CA private key. The default is pem.

-CAserial file
    Use the serial number in file to sign a certificate. The file should consist of one line containing an even number of hex digits with the serial number to use. After each use the serial number is incremented and written out to the file again.

    The default filename consists of the CA certificate file base name with .srl appended. For example, if the CA certificate file is called mycacert.pem, it expects to find a serial number file called mycacert.srl.

-checkend arg
    Check whether the certificate expires in the next arg seconds. If so, exit with return value 1; otherwise exit with return value 0.

-clrext
    Delete any extensions from a certificate. This option is used when a certificate is being created from another certificate (for example with the -signkey or the -CA options). Normally, all extensions are retained.

-days arg
    The number of days to make a certificate valid for. The default is 30 days.

-extensions section
    The section to add certificate extensions from. If this option is not specified, the extensions should either be contained in the unnamed (default) section or the default section should contain a variable called "extensions" which contains the section to use.

-extfile file
    File containing certificate extensions to use. If not specified, no extensions are added to the certificate.

-keyform der | pem
    The format of the private key file used in the -signkey option.

-req
    Expect a certificate request on input instead of a certificate.

-set_serial n
    The serial number to use. This option can be used with either the -signkey or -CA options. If used in conjunction with the -CA option, the serial number file (as specified by the -CAserial or -CAcreateserial options) is not used.

    The serial number can be decimal or hex (if preceded by ‘0x’). Negative serial numbers can also be specified but their use is not recommended.

-signkey file
    Self-sign file using the supplied private key.

    If the input file is a certificate, it sets the issuer name to the subject name (i.e. makes it self-signed), changes the public key to the supplied value, and changes the start and end dates. The start date is set to the current time and the end date is set to a value determined by the -days option. Any certificate extensions are retained unless the -clrext option is supplied.

    If the input is a certificate request, a self-signed certificate is created using the supplied private key using the subject name in the request.

-x509toreq
    Convert a certificate into a certificate request. The -signkey option is used to pass the required private key.

COMMON NOTATION
Several commands share a common syntax, as detailed below.

Password arguments, typically specified using -passin and -passout for input and output passwords, allow passwords to be obtained from a variety of sources. Both of these options take a single argument, described below. If no password argument is given and a password is required, then the user is prompted to enter one: this will typically be read from the current terminal with echoing turned off.

pass:password
    The actual password is password. Since the password is visible to utilities, this form should only be used where security is not important.

env:var
    Obtain the password from the environment variable var. Since the environment of other processes is visible, this option should be used with caution.

file:path
    The first line of path is the password. If the same path argument is supplied to -passin and -passout, then the first line will be used for the input password and the next line for the output password. path need not refer to a regular file: it could, for example, refer to a device or named pipe.

fd:number
    Read the password from the file descriptor number. This can be used to send the data via a pipe, for example.

stdin
    Read the password from standard input.

Input/output formats, typically specified using -inform and -outform, indicate the format being read from or written to. The argument is case insensitive.

der Distinguished Encoding Rules (DER) is a binary format.
net Insecure legacy format.
pem Privacy Enhanced Mail (PEM) is base64-encoded.
pvk Private Key format.
smime
    An SMIME format message.
txt Plain ASCII text.

ENVIRONMENT
The following environment variables affect the execution of openssl:

OPENSSL_CONF
    The location of the master configuration file.

FILES
/etc/ssl/
    Default config directory for openssl.
/etc/ssl/lib/
    Unused.
/etc/ssl/private/
    Default private key directory.
/etc/ssl/openssl.cnf
    Default configuration file for openssl.
/etc/ssl/x509v3.cnf
    Default configuration file for x509 certificates.

SEE ALSO
acme-client(1), nc(1), openssl.cnf(5), x509v3.cnf(5), ssl(8), starttls(8)

STANDARDS
T. Dierks, C. Allen, January 1999, RFC 2246, The TLS Protocol Version 1.0.

M. Wahl, S. Killie, T. Howes, December 1997, RFC 2253, Lightweight Directory Access Protocol (v3): UTF-8 String Representation of Distinguished Names.

B. Kaliski, March 1998, RFC 2315, PKCS #7: Cryptographic Message Syntax Version 1.5.

R. Housley, W. Ford, W. Polk, D. Solo, January 1999, RFC 2459, Internet X.509 Public Key Infrastructure Certificate and CRL Profile.

M. Myers, R. Ankney, A. Malpani, S. Galperin, C. Adams, June 1999, RFC 2560, X.509 Internet Public Key Infrastructure Online Certificate Status Protocol – OCSP.

R. Housley, June 1999, RFC 2630, Cryptographic Message Syntax.

P. Chown, June 2002, RFC 3268, Advanced Encryption Standard (AES) Ciphersuites for Transport Layer Security (TLS).