EVP_CIPHER_NID(3)

NAME
EVP_CIPHER_nid, EVP_CIPHER_CTX_nid, EVP_CIPHER_type, EVP_CIPHER_CTX_type, EVP_CIPHER_block_size, EVP_CIPHER_CTX_block_size, EVP_CIPHER_flags, EVP_CIPHER_CTX_flags, EVP_CIPHER_mode, EVP_CIPHER_CTX_mode - inspect EVP_CIPHER objects

SYNOPSIS
#include <openssl/evp.h>
int
EVP_CIPHER_nid(const EVP_CIPHER *cipher);
int
EVP_CIPHER_CTX_nid(const EVP_CIPHER_CTX *ctx);
int
EVP_CIPHER_type(const EVP_CIPHER *ctx);
int
EVP_CIPHER_CTX_type(const EVP_CIPHER_CTX *ctx);
int
EVP_CIPHER_block_size(const EVP_CIPHER *cipher);
int
EVP_CIPHER_CTX_block_size(const EVP_CIPHER_CTX *ctx);
unsigned long
EVP_CIPHER_flags(const EVP_CIPHER *cipher);
unsigned long
EVP_CIPHER_CTX_flags(const EVP_CIPHER_CTX *ctx);
unsigned long
EVP_CIPHER_mode(const EVP_CIPHER *cipher);
unsigned long
EVP_CIPHER_CTX_mode(const EVP_CIPHER_CTX *ctx);

DESCRIPTION
EVP_CIPHER_nid() returns the numerical identifier (NID) of the cipher. The NID is an internal value which may or may not have a corresponding ASN.1 OBJECT IDENTIFIER; see OBJ_nid2obj(3) for details.

EVP_CIPHER_CTX_nid() returns the NID of the cipher that ctx is configured to use.

EVP_CIPHER_type() returns the NID associated with the ASN.1 OBJECT IDENTIFIER of the cipher, ignoring the cipher parameters. For example, EVP_aes_256_cfb1(3), EVP_aes_256_cfb8(3), and EVP_aes_256_cfb128(3) all return the same NID, NID_aes_256_cfb128.

EVP_CIPHER_CTX_type() returns the NID associated with the ASN.1 OBJECT IDENTIFIER of the cipher that ctx is configured to use.

EVP_CIPHER_block_size() returns the block size of the cipher in bytes. EVP_CIPHER_CTX_block_size() returns the block size of the cipher that ctx is configured to use. Block sizes are guaranteed to be less than or equal to the constant EVP_MAX_BLOCK_LENGTH. Currently, EVP_CipherInit_ex(3) and the other functions documented in the same manual page only support block sizes of 1, 8, and 16 bytes.

EVP_CIPHER_flags() returns the cipher flags used by the cipher. The meaning of the flags is described in the EVP_CIPHER_meth_set_flags(3) manual page.

EVP_CIPHER_CTX_flags() returns the cipher flags of the cipher that ctx is configured to use. Be careful to not confuse these with the unrelated cipher context flags that can be inspected with EVP_CIPHER_CTX_test_flags(3).

EVP_CIPHER_mode() returns the cipher mode, which is the logical AND of the constant EVP_CIPH_MODE and the return value of EVP_CIPHER_flags().

EVP_CIPHER_CTX_mode() returns the cipher mode of the cipher that ctx is configured to use.

RETURN VALUES
EVP_CIPHER_nid() and EVP_CIPHER_CTX_nid() return an NID.

EVP_CIPHER_type() and EVP_CIPHER_CTX_type() return the NID of the cipher's OBJECT IDENTIFIER or NID_undef if it is not associated with an OBJECT IDENTIFIER.

EVP_CIPHER_block_size() and EVP_CIPHER_CTX_block_size() return the block size in bytes.

EVP_CIPHER_flags() and EVP_CIPHER_CTX_flags() return one or more EVP_CIPH_* flag bits OR'ed together.

EVP_CIPHER_mode() and EVP_CIPHER_CTX_mode() return one of the constants EVP_CIPH_ECB_MODE, EVP_CIPH_CBC_MODE, EVP_CIPH_CFB_MODE, EVP_CIPH_OFB_MODE, EVP_CIPH_CTR_MODE, EVP_CIPH_GCM_MODE, EVP_CIPH_CCM_MODE, EVP_CIPH_XTS_MODE, or EVP_CIPH_WRAP_MODE to indicate a block cipher or EVP_CIPH_STREAM_CIPHER to indicate a stream cipher.

SEE ALSO
evp(3), EVP_CIPHER_CTX_ctrl(3), EVP_EncryptInit(3), OBJ_nid2obj(3)

HISTORY
EVP_CIPHER_type(), EVP_CIPHER_CTX_type(), EVP_CIPHER_block_size(), and EVP_CIPHER_CTX_block_size() first appeared in SSLeay 0.6.5. EVP_CIPHER_nid() and EVP_CIPHER_CTX_nid() first appeared in SSLeay 0.8.0. All these functions have been available since OpenBSD 2.4.

EVP_CIPHER_flags(), EVP_CIPHER_CTX_flags(), EVP_CIPHER_mode(), and EVP_CIPHER_CTX_mode() first appeared in OpenSSL 0.9.6 and have been available since OpenBSD 2.9.

CAVEATS
The behaviour of the functions taking an EVP_CIPHER_CTX argument is undefined if they are called on a ctx that has no cipher configured yet, for example one freshly returned from EVP_CIPHER_CTX_new(3). In that case, the program may for example be terminated by a NULL pointer access.