113d40330Schristos=pod 213d40330Schristos 313d40330Schristos=head1 NAME 413d40330Schristos 513d40330SchristosMDC2, MDC2_Init, MDC2_Update, MDC2_Final - MDC2 hash function 613d40330Schristos 713d40330Schristos=head1 SYNOPSIS 813d40330Schristos 913d40330Schristos #include <openssl/mdc2.h> 1013d40330Schristos 11*b0d17251SchristosThe following functions have been deprecated since OpenSSL 3.0, and can be 12*b0d17251Schristoshidden entirely by defining B<OPENSSL_API_COMPAT> with a suitable version value, 13*b0d17251Schristossee L<openssl_user_macros(7)>: 14*b0d17251Schristos 1513d40330Schristos unsigned char *MDC2(const unsigned char *d, unsigned long n, 1613d40330Schristos unsigned char *md); 1713d40330Schristos 1813d40330Schristos int MDC2_Init(MDC2_CTX *c); 1913d40330Schristos int MDC2_Update(MDC2_CTX *c, const unsigned char *data, 2013d40330Schristos unsigned long len); 2113d40330Schristos int MDC2_Final(unsigned char *md, MDC2_CTX *c); 2213d40330Schristos 2313d40330Schristos=head1 DESCRIPTION 2413d40330Schristos 25*b0d17251SchristosAll of the functions described on this page are deprecated. 26*b0d17251SchristosApplications should instead use L<EVP_DigestInit_ex(3)>, L<EVP_DigestUpdate(3)> 27*b0d17251Schristosand L<EVP_DigestFinal_ex(3)>. 28*b0d17251Schristos 2913d40330SchristosMDC2 is a method to construct hash functions with 128 bit output from 3013d40330Schristosblock ciphers. These functions are an implementation of MDC2 with 3113d40330SchristosDES. 3213d40330Schristos 3313d40330SchristosMDC2() computes the MDC2 message digest of the B<n> 3413d40330Schristosbytes at B<d> and places it in B<md> (which must have space for 3513d40330SchristosMDC2_DIGEST_LENGTH == 16 bytes of output). If B<md> is NULL, the digest 3613d40330Schristosis placed in a static array. 3713d40330Schristos 3813d40330SchristosThe following functions may be used if the message is not completely 3913d40330Schristosstored in memory: 4013d40330Schristos 4113d40330SchristosMDC2_Init() initializes a B<MDC2_CTX> structure. 4213d40330Schristos 4313d40330SchristosMDC2_Update() can be called repeatedly with chunks of the message to 4413d40330Schristosbe hashed (B<len> bytes at B<data>). 4513d40330Schristos 4613d40330SchristosMDC2_Final() places the message digest in B<md>, which must have space 4713d40330Schristosfor MDC2_DIGEST_LENGTH == 16 bytes of output, and erases the B<MDC2_CTX>. 4813d40330Schristos 4913d40330SchristosApplications should use the higher level functions 5013d40330SchristosL<EVP_DigestInit(3)> etc. instead of calling the 5113d40330Schristoshash functions directly. 5213d40330Schristos 5313d40330Schristos=head1 RETURN VALUES 5413d40330Schristos 5513d40330SchristosMDC2() returns a pointer to the hash value. 5613d40330Schristos 5713d40330SchristosMDC2_Init(), MDC2_Update() and MDC2_Final() return 1 for success, 0 otherwise. 5813d40330Schristos 5913d40330Schristos=head1 CONFORMING TO 6013d40330Schristos 6113d40330SchristosISO/IEC 10118-2:2000 Hash-Function 2, with DES as the underlying block cipher. 6213d40330Schristos 6313d40330Schristos=head1 SEE ALSO 6413d40330Schristos 6513d40330SchristosL<EVP_DigestInit(3)> 6613d40330Schristos 67*b0d17251Schristos=head1 HISTORY 68*b0d17251Schristos 69*b0d17251SchristosAll of these functions were deprecated in OpenSSL 3.0. 70*b0d17251Schristos 7113d40330Schristos=head1 COPYRIGHT 7213d40330Schristos 73*b0d17251SchristosCopyright 2000-2021 The OpenSSL Project Authors. All Rights Reserved. 7413d40330Schristos 75*b0d17251SchristosLicensed under the Apache License 2.0 (the "License"). You may not use 7613d40330Schristosthis file except in compliance with the License. You can obtain a copy 7713d40330Schristosin the file LICENSE in the source distribution or at 7813d40330SchristosL<https://www.openssl.org/source/license.html>. 7913d40330Schristos 8013d40330Schristos=cut 81