| 1 | =pod
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| 2 |
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| 3 | =head1 NAME
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| 4 |
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| 5 | MDC2, MDC2_Init, MDC2_Update, MDC2_Final - MDC2 hash function
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| 6 |
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| 7 | =head1 SYNOPSIS
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| 8 |
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| 9 | #include <openssl/mdc2.h>
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| 10 |
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| 11 | unsigned char *MDC2(const unsigned char *d, unsigned long n,
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| 12 | unsigned char *md);
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| 13 |
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| 14 | int MDC2_Init(MDC2_CTX *c);
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| 15 | int MDC2_Update(MDC2_CTX *c, const unsigned char *data,
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| 16 | unsigned long len);
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| 17 | int MDC2_Final(unsigned char *md, MDC2_CTX *c);
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| 18 |
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| 19 | =head1 DESCRIPTION
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| 20 |
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| 21 | MDC2 is a method to construct hash functions with 128 bit output from
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| 22 | block ciphers. These functions are an implementation of MDC2 with
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| 23 | DES.
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| 24 |
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| 25 | MDC2() computes the MDC2 message digest of the B<n>
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| 26 | bytes at B<d> and places it in B<md> (which must have space for
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| 27 | MDC2_DIGEST_LENGTH == 16 bytes of output). If B<md> is NULL, the digest
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| 28 | is placed in a static array.
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| 29 |
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| 30 | The following functions may be used if the message is not completely
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| 31 | stored in memory:
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| 32 |
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| 33 | MDC2_Init() initializes a B<MDC2_CTX> structure.
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| 34 |
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| 35 | MDC2_Update() can be called repeatedly with chunks of the message to
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| 36 | be hashed (B<len> bytes at B<data>).
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| 37 |
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| 38 | MDC2_Final() places the message digest in B<md>, which must have space
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| 39 | for MDC2_DIGEST_LENGTH == 16 bytes of output, and erases the B<MDC2_CTX>.
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| 40 |
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| 41 | Applications should use the higher level functions
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| 42 | L<EVP_DigestInit(3)> etc. instead of calling the
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| 43 | hash functions directly.
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| 44 |
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| 45 | =head1 RETURN VALUES
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| 46 |
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| 47 | MDC2() returns a pointer to the hash value.
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| 48 |
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| 49 | MDC2_Init(), MDC2_Update() and MDC2_Final() return 1 for success, 0 otherwise.
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| 50 |
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| 51 | =head1 CONFORMING TO
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| 52 |
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| 53 | ISO/IEC 10118-2:2000 Hash-Function 2, with DES as the underlying block cipher.
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| 54 |
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| 55 | =head1 SEE ALSO
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| 56 |
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| 57 | L<EVP_DigestInit(3)>
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| 58 |
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| 59 | =head1 COPYRIGHT
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| 60 |
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| 61 | Copyright 2000-2017 The OpenSSL Project Authors. All Rights Reserved.
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| 62 |
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| 63 | Licensed under the OpenSSL license (the "License"). You may not use
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| 64 | this file except in compliance with the License. You can obtain a copy
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| 65 | in the file LICENSE in the source distribution or at
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| 66 | L<https://www.openssl.org/source/license.html>.
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| 67 |
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| 68 | =cut
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