evp(3) OpenSSL evp(3)NAMEevp - high-level cryptographic functions
The EVP library provides a high-level interface to cryptographic
EVP_Seal... and EVP_Open... provide public key encryption and
decryption to implement digital "envelopes".
The EVP_Sign... and EVP_Verify... functions implement digital
Symmetric encryption is available with the EVP_Encrypt... functions.
The EVP_Digest... functions provide message digests.
The EVP_PKEY... functions provide a high level interface to asymmetric
Algorithms are loaded with OpenSSL_add_all_algorithms(3).
All the symmetric algorithms (ciphers), digests and asymmetric
algorithms (public key algorithms) can be replaced by ENGINE modules
providing alternative implementations. If ENGINE implementations of
ciphers or digests are registered as defaults, then the various EVP
functions will automatically use those implementations automatically in
preference to built in software implementations. For more information,
consult the engine(3) man page.
Although low level algorithm specific functions exist for many
algorithms their use is discouraged. They cannot be used with an ENGINE
and ENGINE versions of new algorithms cannot be accessed using the low
level functions. Also makes code harder to adapt to new algorithms and
some options are not cleanly supported at the low level and some
operations are more efficient using the high level interface.
SEE ALSOEVP_DigestInit(3), EVP_EncryptInit(3), EVP_OpenInit(3),
EVP_SealInit(3), EVP_SignInit(3), EVP_VerifyInit(3),
OpenSSL_add_all_algorithms(3), engine(3)1.0.1g 2014-03-17 evp(3)