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evp(3ssl) [bsd man page]

evp(3SSL)                                                             OpenSSL                                                            evp(3SSL)

NAME
evp - high-level cryptographic functions SYNOPSIS
#include <openssl/evp.h> DESCRIPTION
The EVP library provides a high-level interface to cryptographic functions. EVP_Seal... and EVP_Open... provide public key encryption and decryption to implement digital "envelopes". The EVP_Sign... and EVP_Verify... functions implement digital signatures. 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. 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 ALSO
EVP_DigestInit(3), EVP_EncryptInit(3), EVP_OpenInit(3), EVP_SealInit(3), EVP_SignInit(3), EVP_VerifyInit(3), OpenSSL_add_all_algorithms(3), engine(3) 1.0.1e 2013-02-11 evp(3SSL)

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OpenSSL_add_all_algorithms(3SSL)				      OpenSSL					  OpenSSL_add_all_algorithms(3SSL)

NAME
OpenSSL_add_all_algorithms, OpenSSL_add_all_ciphers, OpenSSL_add_all_digests - add algorithms to internal table SYNOPSIS
#include <openssl/evp.h> void OpenSSL_add_all_algorithms(void); void OpenSSL_add_all_ciphers(void); void OpenSSL_add_all_digests(void); void EVP_cleanup(void); DESCRIPTION
OpenSSL keeps an internal table of digest algorithms and ciphers. It uses this table to lookup ciphers via functions such as EVP_get_cipher_byname(). OpenSSL_add_all_digests() adds all digest algorithms to the table. OpenSSL_add_all_algorithms() adds all algorithms to the table (digests and ciphers). OpenSSL_add_all_ciphers() adds all encryption algorithms to the table including password based encryption algorithms. EVP_cleanup() removes all ciphers and digests from the table. RETURN VALUES
None of the functions return a value. NOTES
A typical application will call OpenSSL_add_all_algorithms() initially and EVP_cleanup() before exiting. An application does not need to add algorithms to use them explicitly, for example by EVP_sha1(). It just needs to add them if it (or any of the functions it calls) needs to lookup algorithms. The cipher and digest lookup functions are used in many parts of the library. If the table is not initialized several functions will misbehave and complain they cannot find algorithms. This includes the PEM, PKCS#12, SSL and S/MIME libraries. This is a common query in the OpenSSL mailing lists. Calling OpenSSL_add_all_algorithms() links in all algorithms: as a result a statically linked executable can be quite large. If this is important it is possible to just add the required ciphers and digests. BUGS
Although the functions do not return error codes it is possible for them to fail. This will only happen as a result of a memory allocation failure so this is not too much of a problem in practice. SEE ALSO
evp(3), EVP_DigestInit(3), EVP_EncryptInit(3) 1.0.1e 2013-02-11 OpenSSL_add_all_algorithms(3SSL)

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