5 evp - high-level cryptographic functions
9 #include <openssl/evp.h>
13 The EVP library provides a high-level interface to cryptographic
16 B<EVP_Seal>I<...> and B<EVP_Open>I<...> provide public key encryption
17 and decryption to implement digital "envelopes".
19 The B<EVP_Sign>I<...> and B<EVP_Verify>I<...> functions implement
22 Symmetric encryption is available with the B<EVP_Encrypt>I<...>
23 functions. The B<EVP_Digest>I<...> functions provide message digests.
25 The B<EVP_PKEY>I<...> functions provide a high level interface to
26 asymmetric algorithms.
28 The L<B<EVP_Encode>I<...>|EVP_EncodeInit(3)> and
29 L<B<EVP_Decode>I<...>|EVP_EncodeInit(3)> functions implement base 64 encoding
32 Algorithms are loaded with OpenSSL_add_all_algorithms(3).
34 All the symmetric algorithms (ciphers), digests and asymmetric algorithms
35 (public key algorithms) can be replaced by ENGINE modules providing alternative
36 implementations. If ENGINE implementations of ciphers or digests are registered
37 as defaults, then the various EVP functions will automatically use those
38 implementations automatically in preference to built in software
39 implementations. For more information, consult the engine(3) man page.
41 Although low level algorithm specific functions exist for many algorithms
42 their use is discouraged. They cannot be used with an ENGINE and ENGINE
43 versions of new algorithms cannot be accessed using the low level functions.
44 Also makes code harder to adapt to new algorithms and some options are not
45 cleanly supported at the low level and some operations are more efficient
46 using the high level interface.
50 L<EVP_DigestInit(3)|EVP_DigestInit(3)>,
51 L<EVP_EncryptInit(3)|EVP_EncryptInit(3)>,
52 L<EVP_OpenInit(3)|EVP_OpenInit(3)>,
53 L<EVP_SealInit(3)|EVP_SealInit(3)>,
54 L<EVP_SignInit(3)|EVP_SignInit(3)>,
55 L<EVP_VerifyInit(3)|EVP_VerifyInit(3)>,
57 L<OpenSSL_add_all_algorithms(3)|OpenSSL_add_all_algorithms(3)>,
58 L<engine(3)|engine(3)>