openssl/doc/crypto/MDC2_Init.pod
Rich Salz 53934822ac Clean up "generic" intro pod files.
Files like dh.pod, etc., mostly duplicated the API-specific pod files.
Removed the duplicated content; that often mean the whole file could
be removed.  Some of the content about internals got moved into README
files in the source tree.  Some content (e.g., err.pod) got moved
into other pod pages.

Annotate generic pages, remove dup NAME

Reviewed-by: Richard Levitte <levitte@openssl.org>
2016-06-09 16:39:19 -04:00

68 lines
1.8 KiB
Text

=pod
=head1 NAME
MDC2, MDC2_Init, MDC2_Update, MDC2_Final - MDC2 hash function
=head1 SYNOPSIS
#include <openssl/mdc2.h>
unsigned char *MDC2(const unsigned char *d, unsigned long n,
unsigned char *md);
int MDC2_Init(MDC2_CTX *c);
int MDC2_Update(MDC2_CTX *c, const unsigned char *data,
unsigned long len);
int MDC2_Final(unsigned char *md, MDC2_CTX *c);
=head1 DESCRIPTION
MDC2 is a method to construct hash functions with 128 bit output from
block ciphers. These functions are an implementation of MDC2 with
DES.
MDC2() computes the MDC2 message digest of the B<n>
bytes at B<d> and places it in B<md> (which must have space for
MDC2_DIGEST_LENGTH == 16 bytes of output). If B<md> is NULL, the digest
is placed in a static array.
The following functions may be used if the message is not completely
stored in memory:
MDC2_Init() initializes a B<MDC2_CTX> structure.
MDC2_Update() can be called repeatedly with chunks of the message to
be hashed (B<len> bytes at B<data>).
MDC2_Final() places the message digest in B<md>, which must have space
for MDC2_DIGEST_LENGTH == 16 bytes of output, and erases the B<MDC2_CTX>.
Applications should use the higher level functions
L<EVP_DigestInit(3)> etc. instead of calling the
hash functions directly.
=head1 RETURN VALUES
MDC2() returns a pointer to the hash value.
MDC2_Init(), MDC2_Update() and MDC2_Final() return 1 for success, 0 otherwise.
=head1 CONFORMING TO
ISO/IEC 10118-2, with DES
=head1 SEE ALSO
L<EVP_DigestInit(3)>
=head1 COPYRIGHT
Copyright 2000-2016 The OpenSSL Project Authors. All Rights Reserved.
Licensed under the OpenSSL license (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