DragonFly On-Line Manual Pages
OpenSSL_add_all_algorithms(3) OpenSSL OpenSSL_add_all_algorithms(3)
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
OpenSSL_add_all_digests() adds all digest algorithms to the table.
OpenSSL_add_all_algorithms() adds all algorithms to the table (digests
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.
None of the functions return a value.
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.
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)
1.0.2h 2016-05-03 OpenSSL_add_all_algorithms(3)