260 lines
10 KiB
C
260 lines
10 KiB
C
/* sha1-compress.c
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The compression function of the sha1 hash function.
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Copyright (C) 2001, 2004 Peter Gutmann, Andrew Kuchling, Niels Möller
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This file is part of GNU Nettle.
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GNU Nettle is free software: you can redistribute it and/or
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modify it under the terms of either:
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* the GNU Lesser General Public License as published by the Free
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Software Foundation; either version 3 of the License, or (at your
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option) any later version.
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or
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* the GNU General Public License as published by the Free
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Software Foundation; either version 2 of the License, or (at your
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option) any later version.
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or both in parallel, as here.
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GNU Nettle is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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General Public License for more details.
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You should have received copies of the GNU General Public License and
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the GNU Lesser General Public License along with this program. If
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not, see http://www.gnu.org/licenses/.
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*/
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/* Here's the first paragraph of Peter Gutmann's posting,
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* <30ajo5$oe8@ccu2.auckland.ac.nz>:
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*
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* The following is my SHA (FIPS 180) code updated to allow use of the "fixed"
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* SHA, thanks to Jim Gillogly and an anonymous contributor for the information on
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* what's changed in the new version. The fix is a simple change which involves
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* adding a single rotate in the initial expansion function. It is unknown
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* whether this is an optimal solution to the problem which was discovered in the
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* SHA or whether it's simply a bandaid which fixes the problem with a minimum of
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* effort (for example the reengineering of a great many Capstone chips).
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*/
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#if HAVE_CONFIG_H
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# include "config.h"
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#endif
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#ifndef SHA1_DEBUG
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# define SHA1_DEBUG 0
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#endif
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#if SHA1_DEBUG
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# include <stdio.h>
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# define DEBUG(i) \
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fprintf(stderr, "%2d: %8x %8x %8x %8x %8x\n", i, A, B, C, D ,E)
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#else
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# define DEBUG(i)
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#endif
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#include <assert.h>
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#include <stdlib.h>
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#include <string.h>
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#include "sha1.h"
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#include "macros.h"
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/* A block, treated as a sequence of 32-bit words. */
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#define SHA1_DATA_LENGTH 16
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/* The SHA f()-functions. The f1 and f3 functions can be optimized to
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save one boolean operation each - thanks to Rich Schroeppel,
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rcs@cs.arizona.edu for discovering this */
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/* FIXME: Can save a temporary in f3 by using ( (x & y) + (z & (x ^
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y)) ), and then, in the round, compute one of the terms and add it
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into the destination word before computing the second term. Credits
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to George Spelvin for pointing this out. Unfortunately, gcc
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doesn't seem to be smart enough to take advantage of this. */
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/* #define f1(x,y,z) ( ( x & y ) | ( ~x & z ) ) Rounds 0-19 */
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#define f1(x,y,z) ( z ^ ( x & ( y ^ z ) ) ) /* Rounds 0-19 */
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#define f2(x,y,z) ( x ^ y ^ z ) /* Rounds 20-39 */
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/* #define f3(x,y,z) ( ( x & y ) | ( x & z ) | ( y & z ) ) Rounds 40-59 */
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#define f3(x,y,z) ( ( x & y ) | ( z & ( x | y ) ) ) /* Rounds 40-59 */
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#define f4 f2
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/* The SHA Mysterious Constants */
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#define K1 0x5A827999L /* Rounds 0-19 */
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#define K2 0x6ED9EBA1L /* Rounds 20-39 */
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#define K3 0x8F1BBCDCL /* Rounds 40-59 */
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#define K4 0xCA62C1D6L /* Rounds 60-79 */
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/* The initial expanding function. The hash function is defined over an
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80-word expanded input array W, where the first 16 are copies of the input
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data, and the remaining 64 are defined by
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W[ i ] = W[ i - 16 ] ^ W[ i - 14 ] ^ W[ i - 8 ] ^ W[ i - 3 ]
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This implementation generates these values on the fly in a circular
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buffer - thanks to Colin Plumb, colin@nyx10.cs.du.edu for this
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optimization.
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The updated SHA changes the expanding function by adding a rotate of 1
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bit. Thanks to Jim Gillogly, jim@rand.org, and an anonymous contributor
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for this information */
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#define expand(W,i) ( W[ i & 15 ] = \
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ROTL32( 1, ( W[ i & 15 ] ^ W[ (i - 14) & 15 ] ^ \
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W[ (i - 8) & 15 ] ^ W[ (i - 3) & 15 ] ) ) )
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/* The prototype SHA sub-round. The fundamental sub-round is:
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a' = e + ROTL32( 5, a ) + f( b, c, d ) + k + data;
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b' = a;
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c' = ROTL32( 30, b );
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d' = c;
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e' = d;
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but this is implemented by unrolling the loop 5 times and renaming the
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variables ( e, a, b, c, d ) = ( a', b', c', d', e' ) each iteration.
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This code is then replicated 20 times for each of the 4 functions, using
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the next 20 values from the W[] array each time */
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#define subRound(a, b, c, d, e, f, k, data) \
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( e += ROTL32( 5, a ) + f( b, c, d ) + k + data, b = ROTL32( 30, b ) )
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/* For fat builds */
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#if HAVE_NATIVE_sha1_compress
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void
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_nettle_sha1_compress_c(uint32_t *state, const uint8_t *input);
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#define nettle_sha1_compress _nettle_sha1_compress_c
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#endif
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/* Perform the SHA transformation. Note that this code, like MD5, seems to
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break some optimizing compilers due to the complexity of the expressions
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and the size of the basic block. It may be necessary to split it into
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sections, e.g. based on the four subrounds. */
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void
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nettle_sha1_compress(uint32_t *state, const uint8_t *input)
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{
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uint32_t data[SHA1_DATA_LENGTH];
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uint32_t A, B, C, D, E; /* Local vars */
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int i;
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for (i = 0; i < SHA1_DATA_LENGTH; i++, input+= 4)
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{
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data[i] = READ_UINT32(input);
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}
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/* Set up first buffer and local data buffer */
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A = state[0];
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B = state[1];
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C = state[2];
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D = state[3];
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E = state[4];
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DEBUG(-1);
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/* Heavy mangling, in 4 sub-rounds of 20 interations each. */
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subRound( A, B, C, D, E, f1, K1, data[ 0] ); DEBUG(0);
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subRound( E, A, B, C, D, f1, K1, data[ 1] ); DEBUG(1);
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subRound( D, E, A, B, C, f1, K1, data[ 2] );
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subRound( C, D, E, A, B, f1, K1, data[ 3] );
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subRound( B, C, D, E, A, f1, K1, data[ 4] );
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subRound( A, B, C, D, E, f1, K1, data[ 5] );
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subRound( E, A, B, C, D, f1, K1, data[ 6] );
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subRound( D, E, A, B, C, f1, K1, data[ 7] );
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subRound( C, D, E, A, B, f1, K1, data[ 8] );
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subRound( B, C, D, E, A, f1, K1, data[ 9] );
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subRound( A, B, C, D, E, f1, K1, data[10] );
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subRound( E, A, B, C, D, f1, K1, data[11] );
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subRound( D, E, A, B, C, f1, K1, data[12] );
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subRound( C, D, E, A, B, f1, K1, data[13] );
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subRound( B, C, D, E, A, f1, K1, data[14] );
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subRound( A, B, C, D, E, f1, K1, data[15] ); DEBUG(15);
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subRound( E, A, B, C, D, f1, K1, expand( data, 16 ) ); DEBUG(16);
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subRound( D, E, A, B, C, f1, K1, expand( data, 17 ) ); DEBUG(17);
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subRound( C, D, E, A, B, f1, K1, expand( data, 18 ) ); DEBUG(18);
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subRound( B, C, D, E, A, f1, K1, expand( data, 19 ) ); DEBUG(19);
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subRound( A, B, C, D, E, f2, K2, expand( data, 20 ) ); DEBUG(20);
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subRound( E, A, B, C, D, f2, K2, expand( data, 21 ) ); DEBUG(21);
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subRound( D, E, A, B, C, f2, K2, expand( data, 22 ) );
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subRound( C, D, E, A, B, f2, K2, expand( data, 23 ) );
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subRound( B, C, D, E, A, f2, K2, expand( data, 24 ) );
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subRound( A, B, C, D, E, f2, K2, expand( data, 25 ) );
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subRound( E, A, B, C, D, f2, K2, expand( data, 26 ) );
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subRound( D, E, A, B, C, f2, K2, expand( data, 27 ) );
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subRound( C, D, E, A, B, f2, K2, expand( data, 28 ) );
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subRound( B, C, D, E, A, f2, K2, expand( data, 29 ) );
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subRound( A, B, C, D, E, f2, K2, expand( data, 30 ) );
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subRound( E, A, B, C, D, f2, K2, expand( data, 31 ) );
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subRound( D, E, A, B, C, f2, K2, expand( data, 32 ) );
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subRound( C, D, E, A, B, f2, K2, expand( data, 33 ) );
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subRound( B, C, D, E, A, f2, K2, expand( data, 34 ) );
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subRound( A, B, C, D, E, f2, K2, expand( data, 35 ) );
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subRound( E, A, B, C, D, f2, K2, expand( data, 36 ) );
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subRound( D, E, A, B, C, f2, K2, expand( data, 37 ) );
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subRound( C, D, E, A, B, f2, K2, expand( data, 38 ) ); DEBUG(38);
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subRound( B, C, D, E, A, f2, K2, expand( data, 39 ) ); DEBUG(39);
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subRound( A, B, C, D, E, f3, K3, expand( data, 40 ) ); DEBUG(40);
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subRound( E, A, B, C, D, f3, K3, expand( data, 41 ) ); DEBUG(41);
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subRound( D, E, A, B, C, f3, K3, expand( data, 42 ) );
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subRound( C, D, E, A, B, f3, K3, expand( data, 43 ) );
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subRound( B, C, D, E, A, f3, K3, expand( data, 44 ) );
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subRound( A, B, C, D, E, f3, K3, expand( data, 45 ) );
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subRound( E, A, B, C, D, f3, K3, expand( data, 46 ) );
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subRound( D, E, A, B, C, f3, K3, expand( data, 47 ) );
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subRound( C, D, E, A, B, f3, K3, expand( data, 48 ) );
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subRound( B, C, D, E, A, f3, K3, expand( data, 49 ) );
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subRound( A, B, C, D, E, f3, K3, expand( data, 50 ) );
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subRound( E, A, B, C, D, f3, K3, expand( data, 51 ) );
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subRound( D, E, A, B, C, f3, K3, expand( data, 52 ) );
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subRound( C, D, E, A, B, f3, K3, expand( data, 53 ) );
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subRound( B, C, D, E, A, f3, K3, expand( data, 54 ) );
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subRound( A, B, C, D, E, f3, K3, expand( data, 55 ) );
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subRound( E, A, B, C, D, f3, K3, expand( data, 56 ) );
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subRound( D, E, A, B, C, f3, K3, expand( data, 57 ) );
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subRound( C, D, E, A, B, f3, K3, expand( data, 58 ) ); DEBUG(58);
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subRound( B, C, D, E, A, f3, K3, expand( data, 59 ) ); DEBUG(59);
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subRound( A, B, C, D, E, f4, K4, expand( data, 60 ) ); DEBUG(60);
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subRound( E, A, B, C, D, f4, K4, expand( data, 61 ) ); DEBUG(61);
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subRound( D, E, A, B, C, f4, K4, expand( data, 62 ) );
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subRound( C, D, E, A, B, f4, K4, expand( data, 63 ) );
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subRound( B, C, D, E, A, f4, K4, expand( data, 64 ) );
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subRound( A, B, C, D, E, f4, K4, expand( data, 65 ) );
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subRound( E, A, B, C, D, f4, K4, expand( data, 66 ) );
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subRound( D, E, A, B, C, f4, K4, expand( data, 67 ) );
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subRound( C, D, E, A, B, f4, K4, expand( data, 68 ) );
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subRound( B, C, D, E, A, f4, K4, expand( data, 69 ) );
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subRound( A, B, C, D, E, f4, K4, expand( data, 70 ) );
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subRound( E, A, B, C, D, f4, K4, expand( data, 71 ) );
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subRound( D, E, A, B, C, f4, K4, expand( data, 72 ) );
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subRound( C, D, E, A, B, f4, K4, expand( data, 73 ) );
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subRound( B, C, D, E, A, f4, K4, expand( data, 74 ) );
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subRound( A, B, C, D, E, f4, K4, expand( data, 75 ) );
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subRound( E, A, B, C, D, f4, K4, expand( data, 76 ) );
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subRound( D, E, A, B, C, f4, K4, expand( data, 77 ) );
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subRound( C, D, E, A, B, f4, K4, expand( data, 78 ) ); DEBUG(78);
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subRound( B, C, D, E, A, f4, K4, expand( data, 79 ) ); DEBUG(79);
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/* Build message digest */
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state[0] += A;
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state[1] += B;
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state[2] += C;
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state[3] += D;
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state[4] += E;
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#if SHA1_DEBUG
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fprintf(stderr, "99: %8x %8x %8x %8x %8x\n",
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state[0], state[1], state[2], state[3], state[4]);
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#endif
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}
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