OpenSSL_add_all_algorithms, OpenSSL_add_all_ciphers, OpenSSL_add_all_digests,
EVP_cleanup - add algorithms to internal table
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()
adds all digest algorithms to the table.
adds all algorithms to the table (digests
adds all encryption algorithms to the table
including password based encryption algorithms.
removes all ciphers and digests from the table.
None of the functions return a value.
A typical application will call OpenSSL_add_all_algorithms()
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.
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.
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.