mirror of git://git.gnupg.org/gnupg.git
318 lines
7.8 KiB
C
318 lines
7.8 KiB
C
/* sha256.c - SHA256 hash function
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* Copyright (C) 2003 Free Software Foundation, Inc.
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*
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* Please see below for more legal information!
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*
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* This file is part of GnuPG.
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*
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* GnuPG is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* GnuPG 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
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
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*/
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/* Test vectors from FIPS-180-2:
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*
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* "abc"
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* BA7816BF 8F01CFEA 414140DE 5DAE2223 B00361A3 96177A9C B410FF61 F20015AD
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*
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* "abcdbcdecdefdefgefghfghighijhijkijkljklmklmnlmnomnopnopq"
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* 248D6A61 D20638B8 E5C02693 0C3E6039 A33CE459 64FF2167 F6ECEDD4 19DB06C1
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*
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* "a" x 1000000
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* CDC76E5C 9914FB92 81A1C7E2 84D73E67 F1809A48 A497200E 046D39CC C7112CD0
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*/
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#include <config.h>
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#include <string.h>
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#include "util.h"
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#include "algorithms.h"
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typedef struct {
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u32 h0,h1,h2,h3,h4,h5,h6,h7;
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u32 nblocks;
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byte buf[64];
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int count;
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} SHA256_CONTEXT;
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static void
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burn_stack (int bytes)
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{
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char buf[128];
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wipememory(buf,sizeof buf);
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bytes -= sizeof buf;
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if (bytes > 0)
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burn_stack (bytes);
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}
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void
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sha256_init( SHA256_CONTEXT *hd )
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{
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hd->h0 = 0x6a09e667;
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hd->h1 = 0xbb67ae85;
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hd->h2 = 0x3c6ef372;
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hd->h3 = 0xa54ff53a;
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hd->h4 = 0x510e527f;
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hd->h5 = 0x9b05688c;
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hd->h6 = 0x1f83d9ab;
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hd->h7 = 0x5be0cd19;
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hd->nblocks = 0;
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hd->count = 0;
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}
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/****************
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* Transform the message w which consists of 16 32-bit words
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*/
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static void
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transform( SHA256_CONTEXT *hd, byte *data )
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{
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u32 a,b,c,d,e,f,g,h;
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u32 w[64];
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int t;
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static const u32 k[]=
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{
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0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5, 0x3956c25b, 0x59f111f1,
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0x923f82a4, 0xab1c5ed5, 0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3,
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0x72be5d74, 0x80deb1fe, 0x9bdc06a7, 0xc19bf174, 0xe49b69c1, 0xefbe4786,
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0x0fc19dc6, 0x240ca1cc, 0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da,
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0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7, 0xc6e00bf3, 0xd5a79147,
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0x06ca6351, 0x14292967, 0x27b70a85, 0x2e1b2138, 0x4d2c6dfc, 0x53380d13,
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0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85, 0xa2bfe8a1, 0xa81a664b,
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0xc24b8b70, 0xc76c51a3, 0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070,
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0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5, 0x391c0cb3, 0x4ed8aa4a,
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0x5b9cca4f, 0x682e6ff3, 0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208,
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0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2
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};
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/* get values from the chaining vars */
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a = hd->h0;
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b = hd->h1;
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c = hd->h2;
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d = hd->h3;
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e = hd->h4;
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f = hd->h5;
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g = hd->h6;
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h = hd->h7;
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#ifdef BIG_ENDIAN_HOST
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memcpy( w, data, 64 );
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#else
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{
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int i;
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byte *p2;
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for(i=0, p2=(byte*)w; i < 16; i++, p2 += 4 )
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{
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p2[3] = *data++;
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p2[2] = *data++;
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p2[1] = *data++;
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p2[0] = *data++;
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}
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}
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#endif
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#define ROTR(x,n) (((x)>>(n)) | ((x)<<(32-(n))))
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#define Ch(x,y,z) (((x) & (y)) ^ ((~(x)) & (z)))
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#define Maj(x,y,z) (((x) & (y)) ^ ((x) & (z)) ^ ((y) & (z)))
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#define Sum0(x) (ROTR((x),2) ^ ROTR((x),13) ^ ROTR((x),22))
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#define Sum1(x) (ROTR((x),6) ^ ROTR((x),11) ^ ROTR((x),25))
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#define S0(x) (ROTR((x),7) ^ ROTR((x),18) ^ ((x)>>3))
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#define S1(x) (ROTR((x),17) ^ ROTR((x),19) ^ ((x)>>10))
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for(t=16;t<64;t++)
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w[t] = S1(w[t-2]) + w[t-7] + S0(w[t-15]) + w[t-16];
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for(t=0;t<64;t++)
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{
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u32 t1,t2;
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t1=h+Sum1(e)+Ch(e,f,g)+k[t]+w[t];
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t2=Sum0(a)+Maj(a,b,c);
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h=g;
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g=f;
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f=e;
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e=d+t1;
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d=c;
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c=b;
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b=a;
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a=t1+t2;
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/* printf("t=%d a=%08lX b=%08lX c=%08lX d=%08lX e=%08lX f=%08lX g=%08lX h=%08lX\n",t,a,b,c,d,e,f,g,h); */
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}
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/* update chaining vars */
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hd->h0 += a;
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hd->h1 += b;
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hd->h2 += c;
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hd->h3 += d;
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hd->h4 += e;
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hd->h5 += f;
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hd->h6 += g;
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hd->h7 += h;
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}
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/* Update the message digest with the contents
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* of INBUF with length INLEN.
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*/
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static void
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sha256_write( SHA256_CONTEXT *hd, byte *inbuf, size_t inlen)
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{
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if( hd->count == 64 ) { /* flush the buffer */
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transform( hd, hd->buf );
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burn_stack (328);
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hd->count = 0;
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hd->nblocks++;
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}
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if( !inbuf )
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return;
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if( hd->count ) {
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for( ; inlen && hd->count < 64; inlen-- )
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hd->buf[hd->count++] = *inbuf++;
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sha256_write( hd, NULL, 0 );
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if( !inlen )
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return;
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}
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while( inlen >= 64 ) {
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transform( hd, inbuf );
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hd->count = 0;
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hd->nblocks++;
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inlen -= 64;
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inbuf += 64;
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}
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burn_stack (328);
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for( ; inlen && hd->count < 64; inlen-- )
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hd->buf[hd->count++] = *inbuf++;
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}
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/* The routine final terminates the computation and
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* returns the digest.
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* The handle is prepared for a new cycle, but adding bytes to the
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* handle will the destroy the returned buffer.
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* Returns: 32 bytes representing the digest.
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*/
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static void
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sha256_final(SHA256_CONTEXT *hd)
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{
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u32 t, msb, lsb;
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byte *p;
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sha256_write(hd, NULL, 0); /* flush */;
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t = hd->nblocks;
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/* multiply by 64 to make a byte count */
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lsb = t << 6;
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msb = t >> 26;
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/* add the count */
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t = lsb;
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if( (lsb += hd->count) < t )
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msb++;
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/* multiply by 8 to make a bit count */
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t = lsb;
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lsb <<= 3;
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msb <<= 3;
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msb |= t >> 29;
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if( hd->count < 56 ) { /* enough room */
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hd->buf[hd->count++] = 0x80; /* pad */
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while( hd->count < 56 )
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hd->buf[hd->count++] = 0; /* pad */
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}
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else { /* need one extra block */
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hd->buf[hd->count++] = 0x80; /* pad character */
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while( hd->count < 64 )
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hd->buf[hd->count++] = 0;
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sha256_write(hd, NULL, 0); /* flush */;
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memset(hd->buf, 0, 56 ); /* fill next block with zeroes */
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}
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/* append the 64 bit count */
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hd->buf[56] = msb >> 24;
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hd->buf[57] = msb >> 16;
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hd->buf[58] = msb >> 8;
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hd->buf[59] = msb ;
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hd->buf[60] = lsb >> 24;
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hd->buf[61] = lsb >> 16;
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hd->buf[62] = lsb >> 8;
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hd->buf[63] = lsb ;
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transform( hd, hd->buf );
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burn_stack (328);
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p = hd->buf;
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#ifdef BIG_ENDIAN_HOST
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#define X(a) do { *(u32*)p = hd->h##a ; p += 4; } while(0)
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#else /* little endian */
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#define X(a) do { *p++ = hd->h##a >> 24; *p++ = hd->h##a >> 16; \
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*p++ = hd->h##a >> 8; *p++ = hd->h##a; } while(0)
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#endif
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X(0);
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X(1);
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X(2);
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X(3);
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X(4);
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X(5);
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X(6);
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X(7);
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#undef X
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}
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static byte *
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sha256_read( SHA256_CONTEXT *hd )
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{
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return hd->buf;
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}
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/****************
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* Return some information about the algorithm. We need algo here to
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* distinguish different flavors of the algorithm.
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* Returns: A pointer to string describing the algorithm or NULL if
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* the ALGO is invalid.
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*/
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const char *
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sha256_get_info( int algo, size_t *contextsize,
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byte **r_asnoid, int *r_asnlen, int *r_mdlen,
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void (**r_init)( void *c ),
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void (**r_write)( void *c, byte *buf, size_t nbytes ),
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void (**r_final)( void *c ),
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byte *(**r_read)( void *c )
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)
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{
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static byte asn[] = /* Object ID is 2.16.840.1.101.3.4.2.1 */
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{
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0x30, 0x31, 0x30, 0x0d, 0x06, 0x09, 0x60, 0x86,
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0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x01, 0x05,
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0x00, 0x04, 0x20
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};
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if( algo != 8 )
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return NULL;
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*contextsize = sizeof(SHA256_CONTEXT);
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*r_asnoid = asn;
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*r_asnlen = DIM(asn);
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*r_mdlen = 32;
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*(void (**)(SHA256_CONTEXT *))r_init = sha256_init;
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*(void (**)(SHA256_CONTEXT *, byte*, size_t))r_write = sha256_write;
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*(void (**)(SHA256_CONTEXT *))r_final = sha256_final;
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*(byte *(**)(SHA256_CONTEXT *))r_read = sha256_read;
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return "SHA256";
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}
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