=pod

=head1 NAME

EVP_sha224,
EVP_sha256,
EVP_sha512_224,
EVP_sha512_256,
EVP_sha384,
EVP_sha512
- SHA-2 For EVP

=head1 SYNOPSIS

 #include <openssl/evp.h>

 const EVP_MD *EVP_sha224(void);
 const EVP_MD *EVP_sha256(void);
 const EVP_MD *EVP_sha512_224(void);
 const EVP_MD *EVP_sha512_256(void);
 const EVP_MD *EVP_sha384(void);
 const EVP_MD *EVP_sha512(void);

=head1 DESCRIPTION

SHA-2 (Secure Hash Algorithm 2) is a family of cryptographic hash functions
standardized in NIST FIPS 180-4, first published in 2001.

=over 4

=item EVP_sha224(),
EVP_sha256(),
EVP_sha512_224,
EVP_sha512_256,
EVP_sha384(),
EVP_sha512()

The SHA-2 SHA-224, SHA-256, SHA-512/224, SHA512/256, SHA-384 and SHA-512
algorithms, which generate 224, 256, 224, 256, 384 and 512 bits
respectively of output from a given input.

The two algorithms: SHA-512/224 and SHA512/256 are truncated forms of the
SHA-512 algorithm. They are distinct from SHA-224 and SHA-256 even though
their outputs are of the same size.

=back

=head1 NOTES

Developers should be aware of the negative performance implications of
calling these functions multiple times and should consider using
L<EVP_MD_fetch(3)> with L<EVP_MD-SHA2(7)>instead.
See L<crypto(7)/Performance> for further information.

=head1 RETURN VALUES

These functions return a B<EVP_MD> structure that contains the
implementation of the message digest. See L<EVP_MD_meth_new(3)> for
details of the B<EVP_MD> structure.

=head1 CONFORMING TO

NIST FIPS 180-4.

=head1 SEE ALSO

L<evp(7)>,
L<EVP_DigestInit(3)>

=head1 COPYRIGHT

Copyright 2017-2023 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

