.\"	$OpenBSD: OpenSSL_add_all_algorithms.3,v 1.4 2016/11/28 16:40:27 schwarze Exp $
.\"	OpenSSL f672aee4 Feb 9 11:52:40 2016 -0500
.\"
.\" This file was written by Dr. Stephen Henson <steve@openssl.org>.
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.Dd $Mdocdate: November 28 2016 $
.Dt OPENSSL_ADD_ALL_ALGORITHMS 3
.Os
.Sh NAME
.Nm OpenSSL_add_all_algorithms ,
.Nm OpenSSL_add_all_ciphers ,
.Nm OpenSSL_add_all_digests ,
.Nm EVP_cleanup
.Nd add algorithms to internal table
.Sh SYNOPSIS
.In openssl/evp.h
.Ft void
.Fn OpenSSL_add_all_algorithms void
.Ft void
.Fn OpenSSL_add_all_ciphers void
.Ft void
.Fn OpenSSL_add_all_digests void
.Ft void
.Fn EVP_cleanup void
.Sh DESCRIPTION
OpenSSL keeps an internal table of digest algorithms and ciphers.
It uses this table to look up ciphers via functions such as
.Xr EVP_get_cipherbyname 3 .
.Pp
.Fn OpenSSL_add_all_algorithms
adds all algorithms to the table (digests and ciphers).
.Pp
.Fn OpenSSL_add_all_digests
adds all digest algorithms to the table.
.Pp
.Fn OpenSSL_add_all_ciphers
adds all encryption algorithms to the table including password based
encryption algorithms.
.Pp
.Fn EVP_cleanup
removes all ciphers and digests from the table.
.Pp
A typical application will call
.Fn OpenSSL_add_all_algorithms
initially and
.Fn EVP_cleanup
before exiting.
.Pp
An application does not need to add algorithms to use them explicitly,
for example by
.Xr EVP_sha1 3 .
It just needs to add them if it (or any of the functions it calls) needs
to look up algorithms.
.Pp
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.
.Pp
Calling
.Fn 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.
.Sh SEE ALSO
.Xr evp 3 ,
.Xr EVP_DigestInit 3 ,
.Xr EVP_EncryptInit 3
.Sh 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.