SHA1 数字签名算法实现

/* * sha1.c * * Created on: 2011-10-29 * Author: Administrator */ #include "sha1.h" void init() { h0 = 0x67452301; h1 = 0xEFCDAB89; h2 = 0x98BADCFE; h3 = 0x10325476; h4 = 0xC3D2E1F0; } /* * data 待处理字符串 非空 * blen data的字节数 必须为0~63的数 * sumlen 总字节数 * 先补一个1，然后再补0，直到长度满足对512取模后余数是448 * * 补位，最多512位(即补全了该组再补充一组) * 操作仅限于0~PREBUFLEN - 1 */ int Postprocessing(const unsigned char *data, unsigned blen, unsigned long sumlen) { if (!data || blen > 63 || blen < 0) //非空且大小合适 return shaStateError; int llen = blen / 4; int ylen = blen % 4; int i = 0, j = 0; for (i = 0; i < llen; i++) //凑够多少个4字节 { W[i] = data[j++] << 24; W[i] |= data[j++] << 16; W[i] |= data[j++] << 8; W[i] |= data[j++]; } switch (ylen) //剩下的单字节,填充W[i] { case 0: W[i] = 0x80 << 24; //数据后面添加一个1 break; case 1: W[i] = data[j++] << 24; W[i] |= 0x80 << 16; //数据后面添加一个1 W[i] &= ~0xffff; break; case 2: W[i] = data[j++] << 24; W[i] |= data[j++] << 16; W[i] |= 0x80 << 8; //数据后面添加一个1 W[i] &= ~0xff; break; case 3: W[i] = data[j++] << 24; W[i] |= data[j++] << 16; W[i] |= data[j++] << 8; W[i] |= 0x80; //数据后面添加一个1 break; } i++; for (; i < PREBUFLEN; i++) //后面全清零 W[i] = 0; if (blen > 55) //必需再增加一块 { calOneW(); //计算刚组建好的那一块，然后后面组建下一补充块 for (i = 0; i < PREBUFLEN; i++) { W[i] = 0; //W全清零 } } W[PREBUFLEN - 2] = sumlen >> 27; //数据长度 W[PREBUFLEN - 1] = sumlen << 3; //calOneW(); //计算最后一块 } /* * 扩展16个字到80个字 */ void Extend() { int i; for (i = 16; i < BUFLEN; i++) { W[i] = W[i - 3] ^ W[i - 8] ^ W[i - 14] ^ W[i - 16]; W[i] = S(1,W[i]); } /*int ii = 0; for (ii = 0; ii < 80; ii++) { printf("%x", W[ii]); if (ii % 10 == 9) printf("\n"); }*/ } /* * 计算 * 计算输入：16字节，h0~h4 */ void calOneW() { Extend(); //扩展空间到80字 //初始化 a = h0; b = h1; c = h2; d = h3; e = h4; //计算 int i; unsigned long temp, f, k; for (i = 0; i < BUFLEN; i++) { if (i >= 0 && i <= 19) { f = (b & c) | ((~b) & d); k = 0x5A827999; } else if (i > 19 && i <= 39) { f = b ^ c ^ d; k = 0x6ED9EBA1; } else if (i > 39 && i <= 59) { f = (b & c) | (b & d) | (c & d); k = 0x8F1BBCDC; } else if (i > 59 && i <= 79) { f = b ^ c ^ d; k = 0xCA62C1D6; } temp = S(5,a) + f + e + k + W[i]; e = d; d = c; c = S(30,b); b = a; a = temp; } //printf("%x %x %x %x %x \n", a, b, c, d, e); h0 += a; h1 += b; h2 += c; h3 += d; h4 += e; } /* * divide the data into several blocks ,every is 512 bits. * then cal them one by one and then extend the last one and cal it */ int cal(unsigned char * data, unsigned long len, unsigned long result[5]) { /*int xx=0; for(xx=0;xx<len;xx++) printf("%x ",data[xx]); printf("\n");*/ init(); int t = len / (PREBUFLEN << 2); //总共需要几次完整数据块 int yu = len % (PREBUFLEN << 2); //剩下的字节数 //printf("%lu %d %d\n\n",len,t,yu); int i, j; unsigned long p = 0; for (i = 0; i < t; i++) { for (j = 0; j < PREBUFLEN; j++) { W[j] = data[p++] << 24; //第一次为赋值，相当于清零然后赋值 W[j] |= data[p++] << 16; W[j] |= data[p++] << 8; W[j] |= data[p++]; } calOneW(); //计算该块 } Postprocessing(&data[p], yu, len); calOneW(); //计算该块 result[0] = h0; result[1] = h1; result[2] = h2; result[3] = h3; result[4] = h4; return shaSuccess; }