=pod

=head1 NAME

OSSL_PROVIDER-legacy - OpenSSL legacy provider

=head1 DESCRIPTION

The OpenSSL legacy provider supplies OpenSSL implementations of algorithms
that have been deemed legacy.  Such algorithms have commonly fallen out of
use, have been deemed insecure by the cryptography community, or something
similar.

We can consider this the retirement home of cryptographic algorithms.

=head2 Properties

The implementations in this provider specifically has this property
defined:

=over 4

=item "provider=legacy"

=back

It may be used in a property query string with fetching functions such as
L<EVP_MD_fetch(3)> or L<EVP_CIPHER_fetch(3)>, as well as with other
functions that take a property query string, such as
L<EVP_PKEY_CTX_new_from_name(3)>.

It isn't mandatory to query for any of these properties, except to
make sure to get implementations of this provider and none other.

=head1 OPERATIONS AND ALGORITHMS

The OpenSSL legacy provider supports these operations and algorithms:

=head2 Hashing Algorithms / Message Digests

=over 4

=item MD2, see L<EVP_MD-MD2(7)>

=item MD4, see L<EVP_MD-MD4(7)>

=item MDC2, see L<EVP_MD-MDC2(7)>

=item WHIRLPOOL, see L<EVP_MD-WHIRLPOOL(7)>

=item RIPEMD160, see L<EVP_MD-RIPEMD160(7)>

=back

=begin comment

When algorithms for other operations start appearing, the
following =head2 titles are appropriate to use:

- Symmetric Ciphers

- Message Authentication Code (MAC)

- Key Derivation Function (KDF)

- Key Exchange

- Signature

- Asymmetric Cipher

- Asymmetric Key Management

=end comment

=head1 SEE ALSO

L<OSSL_PARAM(3)>,
L<openssl-core.h(7)>,
L<openssl-core_dispatch.h(7)>,
L<provider(7)>

=head1 COPYRIGHT

Copyright 2020 The OpenSSL Project Authors. All Rights Reserved.

Licensed under the Apache License 2.0 (the "License").  You may not use
this file except in compliance with the License.  You can obtain a copy
in the file LICENSE in the source distribution or at
L<https://www.openssl.org/source/license.html>.

=cut