OpenSSL_add_all_digests - 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().
OpenSSL_add_all_digests() adds all digest algorithms to
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
None of the functions return a value.
A typical application will call OpenSSL_add_all_algo-
rithms() 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
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
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.
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.
evp(3), EVP_DigestInit(3), EVP_EncryptInit(3)
OpenBSD 3.6 2000-12-14 2 [ Back ]