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)