sha1.cpp

只包括两个核心文件sha1.cpp及sha1.h 计算数据的sha1摘要。简单

#include "stdafx.h"
#include "sha1.h"

#define SHA1HANDSOFF

#define rol(value, bits) (((value) << (bits)) | ((value) >> (32 - (bits))))

/* blk0() and blk() perform the initial expand. */
/* I got the idea of expanding during the round function from SSLeay */
#ifndef WORDS_BIGENDIAN
#define blk0(i) (block->l[i] = (rol(block->l[i], 24) & 0xFF00FF00) | \
        (rol(block->l[i], 8) & 0x00FF00FF))
#else
#define blk0(i) block->l[i]
#endif
#define blk(i) (block->l[i & 15] = rol(block->l[(i + 13) & 15] ^ \
        block->l[(i + 8) & 15] ^ block->l[(i + 2) & 15] ^ block->l[i & 15], 1))

/* (R0+R1), R2, R3, R4 are the different operations used in SHA1 */
#define R0(v,w,x,y,z,i) \
        z += ((w & (x ^ y)) ^ y) + blk0(i) + 0x5A827999 + rol(v, 5); \
        w = rol(w, 30);
#define R1(v,w,x,y,z,i) \
        z += ((w & (x ^ y)) ^ y) + blk(i) + 0x5A827999 + rol(v, 5); \
        w = rol(w, 30);
#define R2(v,w,x,y,z,i) \
        z += (w ^ x ^ y) + blk(i) + 0x6ED9EBA1 + rol(v, 5); w = rol(w, 30);
#define R3(v,w,x,y,z,i) \
        z += (((w | x) & y) | (w & x)) + blk(i) + 0x8F1BBCDC + rol(v, 5); \
        w = rol(w, 30);
#define R4(v,w,x,y,z,i) \
        z += (w ^ x ^ y) + blk(i) + 0xCA62C1D6 + rol(v, 5); \
        w=rol(w, 30);


#ifdef VERBOSE  /* SAK */
void SHAPrintContext(SHA1_CTX *context, char *msg)
{
        printf("%s (%d,%d) %x %x %x %x %x\n",
               msg,
               context->count[0], context->count[1], 
               context->state[0],
               context->state[1],
               context->state[2],
               context->state[3],
               context->state[4]);
}
#endif

/* Hash a single 512-bit block. This is the core of the algorithm. */

void SHA1Transform(u32 state[5], const unsigned char buffer[64])
{
        u32 a, b, c, d, e;
        typedef union {
                unsigned char c[64];
                u32 l[16];
        } CHAR64LONG16;
        CHAR64LONG16* block;
#ifdef SHA1HANDSOFF
        u32 workspace[16];
        block = (CHAR64LONG16 *) workspace;
        memcpy(block, buffer, 64);
#else
        block = (CHAR64LONG16 *) buffer;
#endif
        /* Copy context->state[] to working vars */
        a = state[0];
        b = state[1];
        c = state[2];
        d = state[3];
        e = state[4];
        /* 4 rounds of 20 operations each. Loop unrolled. */
        R0(a,b,c,d,e, 0); R0(e,a,b,c,d, 1); R0(d,e,a,b,c, 2); R0(c,d,e,a,b, 3);
        R0(b,c,d,e,a, 4); R0(a,b,c,d,e, 5); R0(e,a,b,c,d, 6); R0(d,e,a,b,c, 7);
        R0(c,d,e,a,b, 8); R0(b,c,d,e,a, 9); R0(a,b,c,d,e,10); R0(e,a,b,c,d,11);
        R0(d,e,a,b,c,12); R0(c,d,e,a,b,13); R0(b,c,d,e,a,14); R0(a,b,c,d,e,15);
        R1(e,a,b,c,d,16); R1(d,e,a,b,c,17); R1(c,d,e,a,b,18); R1(b,c,d,e,a,19);
        R2(a,b,c,d,e,20); R2(e,a,b,c,d,21); R2(d,e,a,b,c,22); R2(c,d,e,a,b,23);
        R2(b,c,d,e,a,24); R2(a,b,c,d,e,25); R2(e,a,b,c,d,26); R2(d,e,a,b,c,27);
        R2(c,d,e,a,b,28); R2(b,c,d,e,a,29); R2(a,b,c,d,e,30); R2(e,a,b,c,d,31);
        R2(d,e,a,b,c,32); R2(c,d,e,a,b,33); R2(b,c,d,e,a,34); R2(a,b,c,d,e,35);
        R2(e,a,b,c,d,36); R2(d,e,a,b,c,37); R2(c,d,e,a,b,38); R2(b,c,d,e,a,39);
        R3(a,b,c,d,e,40); R3(e,a,b,c,d,41); R3(d,e,a,b,c,42); R3(c,d,e,a,b,43);
        R3(b,c,d,e,a,44); R3(a,b,c,d,e,45); R3(e,a,b,c,d,46); R3(d,e,a,b,c,47);
        R3(c,d,e,a,b,48); R3(b,c,d,e,a,49); R3(a,b,c,d,e,50); R3(e,a,b,c,d,51);
        R3(d,e,a,b,c,52); R3(c,d,e,a,b,53); R3(b,c,d,e,a,54); R3(a,b,c,d,e,55);
        R3(e,a,b,c,d,56); R3(d,e,a,b,c,57); R3(c,d,e,a,b,58); R3(b,c,d,e,a,59);
        R4(a,b,c,d,e,60); R4(e,a,b,c,d,61); R4(d,e,a,b,c,62); R4(c,d,e,a,b,63);
        R4(b,c,d,e,a,64); R4(a,b,c,d,e,65); R4(e,a,b,c,d,66); R4(d,e,a,b,c,67);
        R4(c,d,e,a,b,68); R4(b,c,d,e,a,69); R4(a,b,c,d,e,70); R4(e,a,b,c,d,71);
        R4(d,e,a,b,c,72); R4(c,d,e,a,b,73); R4(b,c,d,e,a,74); R4(a,b,c,d,e,75);
        R4(e,a,b,c,d,76); R4(d,e,a,b,c,77); R4(c,d,e,a,b,78); R4(b,c,d,e,a,79);
        /* Add the working vars back into context.state[] */
        state[0] += a;
        state[1] += b;
        state[2] += c;
        state[3] += d;
        state[4] += e;
        /* Wipe variables */
        a = b = c = d = e = 0;
#ifdef SHA1HANDSOFF
        memset(block, 0, 64);
#endif
}


/* SHA1Init - Initialize new context */

void SHA1Init(SHA1_CTX* context)
{
        /* SHA1 initialization constants */
        context->state[0] = 0x67452301;
        context->state[1] = 0xEFCDAB89;
        context->state[2] = 0x98BADCFE;
        context->state[3] = 0x10325476;
        context->state[4] = 0xC3D2E1F0;
        context->count[0] = context->count[1] = 0;
}


/* Run your data through this. */

void SHA1Update(SHA1_CTX* context, unsigned char const *_data, u32 len)
{
        u32 i, j;
        const unsigned char *data = _data;

#ifdef VERBOSE
        SHAPrintContext(context, "before");
#endif
        j = (context->count[0] >> 3) & 63;
        if ((context->count[0] += len << 3) < (len << 3))
                context->count[1]++;
        context->count[1] += (len >> 29);
        if ((j + len) > 63) {
                memcpy(&context->buffer[j], data, (i = 64-j));
                SHA1Transform(context->state, context->buffer);
                for ( ; i + 63 < len; i += 64) {
                        SHA1Transform(context->state, &data[i]);
                }
                j = 0;
        }
        else i = 0;
        memcpy(&context->buffer[j], &data[i], len - i);
#ifdef VERBOSE
        SHAPrintContext(context, "after ");
#endif
}


/* Add padding and return the message digest. */

void SHA1Final(unsigned char digest[20], SHA1_CTX* context)
{
        u32 i;
        unsigned char finalcount[8];

        for (i = 0; i < 8; i++) {
                finalcount[i] = (unsigned char)
                        ((context->count[(i >= 4 ? 0 : 1)] >>
                          ((3-(i & 3)) * 8) ) & 255);  /* Endian independent */
        }
        SHA1Update(context, (unsigned char *) "\200", 1);
        while ((context->count[0] & 504) != 448) {
                SHA1Update(context, (unsigned char *) "\0", 1);
        }
        SHA1Update(context, finalcount, 8);  /* Should cause a SHA1Transform()
                                              */
        for (i = 0; i < 20; i++) {
                digest[i] = (unsigned char)
                        ((context->state[i >> 2] >> ((3 - (i & 3)) * 8)) &
                         255);
        }
        /* Wipe variables */
        i = 0;
        memset(context->buffer, 0, 64);
        memset(context->state, 0, 20);
        memset(context->count, 0, 8);
        memset(finalcount, 0, 8);
}