C语言获取文件的SHA1哈希值
安全哈希算法(Secure Hash Algorithm)主要适用于数字签名标准 (Digital Signature Standard DSS)里面定义的数字签名算法(Digital Signature Algorithm DSA)。对于长度小于2^64位的消息,SHA1会产生一个160位的消息摘要。当接收到消息的时候,这个消息摘要可以用来验证数据的完整性。在传输的过程中,数据很可能会发生变化,那么这时候就会产生不同的消息摘要。 SHA1有如下特性:不可以从消息摘要中复原信息;两个不同的消息不会产生同样的消息摘要。
SHA1 C语言实现
#include <stdio.h> #include <stdlib.h> #include <string.h> #include <assert.h> #include <errno.h> #undef BIG_ENDIAN_HOST typedef unsigned int u32; /**************** * Rotate a 32 bit integer by n bytes */ #if defined(__GNUC__) && defined(__i386__) static inline u32 rol( u32 x, int n) { __asm__("roll %%cl,%0" :"=r" (x) :"0" (x),"c" (n)); return x; } #else #define rol(x,n) ( ((x) << (n)) | ((x) >> (32-(n))) ) #endif typedef struct { u32 h0,h1,h2,h3,h4; u32 nblocks; unsigned char buf[64]; int count; } SHA1_CONTEXT; void sha1_init( SHA1_CONTEXT *hd ) { hd->h0 = 0x67452301; hd->h1 = 0xefcdab89; hd->h2 = 0x98badcfe; hd->h3 = 0x10325476; hd->h4 = 0xc3d2e1f0; hd->nblocks = 0; hd->count = 0; } /**************** * Transform the message X which consists of 16 32-bit-words */ static void transform( SHA1_CONTEXT *hd, unsigned char *data ) { u32 a,b,c,d,e,tm; u32 x[16]; /* get values from the chaining vars */ a = hd->h0; b = hd->h1; c = hd->h2; d = hd->h3; e = hd->h4; #ifdef BIG_ENDIAN_HOST memcpy( x, data, 64 ); #else { int i; unsigned char *p2; for(i=0, p2=(unsigned char*)x; i < 16; i++, p2 += 4 ) { p2[3] = *data++; p2[2] = *data++; p2[1] = *data++; p2[0] = *data++; } } #endif #define K1 0x5A827999L #define K2 0x6ED9EBA1L #define K3 0x8F1BBCDCL #define K4 0xCA62C1D6L #define F1(x,y,z) ( z ^ ( x & ( y ^ z ) ) ) #define F2(x,y,z) ( x ^ y ^ z ) #define F3(x,y,z) ( ( x & y ) | ( z & ( x | y ) ) ) #define F4(x,y,z) ( x ^ y ^ z ) #define M(i) ( tm = x[i&0x0f] ^ x[(i-14)&0x0f] ^ x[(i-8)&0x0f] ^ x[(i-3)&0x0f] , (x[i&0x0f] = rol(tm,1)) ) #define R(a,b,c,d,e,f,k,m) do { e += rol( a, 5 ) + f( b, c, d ) + k + m; b = rol( b, 30 ); } while(0) R( a, b, c, d, e, F1, K1, x[ 0] ); R( e, a, b, c, d, F1, K1, x[ 1] ); R( d, e, a, b, c, F1, K1, x[ 2] ); R( c, d, e, a, b, F1, K1, x[ 3] ); R( b, c, d, e, a, F1, K1, x[ 4] ); R( a, b, c, d, e, F1, K1, x[ 5] ); R( e, a, b, c, d, F1, K1, x[ 6] ); R( d, e, a, b, c, F1, K1, x[ 7] ); R( c, d, e, a, b, F1, K1, x[ 8] ); R( b, c, d, e, a, F1, K1, x[ 9] ); R( a, b, c, d, e, F1, K1, x[10] ); R( e, a, b, c, d, F1, K1, x[11] ); R( d, e, a, b, c, F1, K1, x[12] ); R( c, d, e, a, b, F1, K1, x[13] ); R( b, c, d, e, a, F1, K1, x[14] ); R( a, b, c, d, e, F1, K1, x[15] ); R( e, a, b, c, d, F1, K1, M(16) ); R( d, e, a, b, c, F1, K1, M(17) ); R( c, d, e, a, b, F1, K1, M(18) ); R( b, c, d, e, a, F1, K1, M(19) ); R( a, b, c, d, e, F2, K2, M(20) ); R( e, a, b, c, d, F2, K2, M(21) ); R( d, e, a, b, c, F2, K2, M(22) ); R( c, d, e, a, b, F2, K2, M(23) ); R( b, c, d, e, a, F2, K2, M(24) ); R( a, b, c, d, e, F2, K2, M(25) ); R( e, a, b, c, d, F2, K2, M(26) ); R( d, e, a, b, c, F2, K2, M(27) ); R( c, d, e, a, b, F2, K2, M(28) ); R( b, c, d, e, a, F2, K2, M(29) ); R( a, b, c, d, e, F2, K2, M(30) ); R( e, a, b, c, d, F2, K2, M(31) ); R( d, e, a, b, c, F2, K2, M(32) ); R( c, d, e, a, b, F2, K2, M(33) ); R( b, c, d, e, a, F2, K2, M(34) ); R( a, b, c, d, e, F2, K2, M(35) ); R( e, a, b, c, d, F2, K2, M(36) ); R( d, e, a, b, c, F2, K2, M(37) ); R( c, d, e, a, b, F2, K2, M(38) ); R( b, c, d, e, a, F2, K2, M(39) ); R( a, b, c, d, e, F3, K3, M(40) ); R( e, a, b, c, d, F3, K3, M(41) ); R( d, e, a, b, c, F3, K3, M(42) ); R( c, d, e, a, b, F3, K3, M(43) ); R( b, c, d, e, a, F3, K3, M(44) ); R( a, b, c, d, e, F3, K3, M(45) ); R( e, a, b, c, d, F3, K3, M(46) ); R( d, e, a, b, c, F3, K3, M(47) ); R( c, d, e, a, b, F3, K3, M(48) ); R( b, c, d, e, a, F3, K3, M(49) ); R( a, b, c, d, e, F3, K3, M(50) ); R( e, a, b, c, d, F3, K3, M(51) ); R( d, e, a, b, c, F3, K3, M(52) ); R( c, d, e, a, b, F3, K3, M(53) ); R( b, c, d, e, a, F3, K3, M(54) ); R( a, b, c, d, e, F3, K3, M(55) ); R( e, a, b, c, d, F3, K3, M(56) ); R( d, e, a, b, c, F3, K3, M(57) ); R( c, d, e, a, b, F3, K3, M(58) ); R( b, c, d, e, a, F3, K3, M(59) ); R( a, b, c, d, e, F4, K4, M(60) ); R( e, a, b, c, d, F4, K4, M(61) ); R( d, e, a, b, c, F4, K4, M(62) ); R( c, d, e, a, b, F4, K4, M(63) ); R( b, c, d, e, a, F4, K4, M(64) ); R( a, b, c, d, e, F4, K4, M(65) ); R( e, a, b, c, d, F4, K4, M(66) ); R( d, e, a, b, c, F4, K4, M(67) ); R( c, d, e, a, b, F4, K4, M(68) ); R( b, c, d, e, a, F4, K4, M(69) ); R( a, b, c, d, e, F4, K4, M(70) ); R( e, a, b, c, d, F4, K4, M(71) ); R( d, e, a, b, c, F4, K4, M(72) ); R( c, d, e, a, b, F4, K4, M(73) ); R( b, c, d, e, a, F4, K4, M(74) ); R( a, b, c, d, e, F4, K4, M(75) ); R( e, a, b, c, d, F4, K4, M(76) ); R( d, e, a, b, c, F4, K4, M(77) ); R( c, d, e, a, b, F4, K4, M(78) ); R( b, c, d, e, a, F4, K4, M(79) ); /* Update chaining vars */ hd->h0 += a; hd->h1 += b; hd->h2 += c; hd->h3 += d; hd->h4 += e; } /* Update the message digest with the contents * of INBUF with length INLEN. */ static void sha1_write( SHA1_CONTEXT *hd, unsigned char *inbuf, size_t inlen) { if( hd->count == 64 ) { /* flush the buffer */ transform( hd, hd->buf ); hd->count = 0; hd->nblocks++; } if( !inbuf ) return; if( hd->count ) { for( ; inlen && hd->count < 64; inlen-- ) hd->buf[hd->count++] = *inbuf++; sha1_write( hd, NULL, 0 ); if( !inlen ) return; } while( inlen >= 64 ) { transform( hd, inbuf ); hd->count = 0; hd->nblocks++; inlen -= 64; inbuf += 64; } for( ; inlen && hd->count < 64; inlen-- ) hd->buf[hd->count++] = *inbuf++; } /* The routine final terminates the computation and * returns the digest. * The handle is prepared for a new cycle, but adding bytes to the * handle will the destroy the returned buffer. * Returns: 20 bytes representing the digest. */ static void sha1_final(SHA1_CONTEXT *hd) { u32 t, msb, lsb; unsigned char *p; sha1_write(hd, NULL, 0); /* flush */; t = hd->nblocks; /* multiply by 64 to make a byte count */ lsb = t << 6; msb = t >> 26; /* add the count */ t = lsb; if( (lsb += hd->count) < t ) msb++; /* multiply by 8 to make a bit count */ t = lsb; lsb <<= 3; msb <<= 3; msb |= t >> 29; if( hd->count < 56 ) { /* enough room */ hd->buf[hd->count++] = 0x80; /* pad */ while( hd->count < 56 ) hd->buf[hd->count++] = 0; /* pad */ } else { /* need one extra block */ hd->buf[hd->count++] = 0x80; /* pad character */ while( hd->count < 64 ) hd->buf[hd->count++] = 0; sha1_write(hd, NULL, 0); /* flush */; memset(hd->buf, 0, 56 ); /* fill next block with zeroes */ } /* append the 64 bit count */ hd->buf[56] = msb >> 24; hd->buf[57] = msb >> 16; hd->buf[58] = msb >> 8; hd->buf[59] = msb ; hd->buf[60] = lsb >> 24; hd->buf[61] = lsb >> 16; hd->buf[62] = lsb >> 8; hd->buf[63] = lsb ; transform( hd, hd->buf ); p = hd->buf; #ifdef BIG_ENDIAN_HOST #define X(a) do { *(u32*)p = hd->h##a ; p += 4; } while(0) #else /* little endian */ #define X(a) do { *p++ = hd->h##a >> 24; *p++ = hd->h##a >> 16; *p++ = hd->h##a >> 8; *p++ = hd->h##a; } while(0) #endif X(0); X(1); X(2); X(3); X(4); #undef X }
控制台调用函数:
/*输出文件的SHA1值 * FileNameInPut:文件路径 */ void GetFileSHA1(char *FileNameInPut) { if(FileNameInPut==NULL) { printf("\nUsage:\n <EXEFILE> <FILENAME>\n "); return; } FILE *fp; char buffer[4096]; size_t n; SHA1_CONTEXT ctx; int i; fopen_s (&fp, FileNameInPut, "rb"); if (!fp) { printf("打开文件“%s”失败\n", FileNameInPut); return; } sha1_init (&ctx); while ( (n = fread (buffer, 1, sizeof buffer, fp))) sha1_write (&ctx, (unsigned char *)buffer, n); if (ferror (fp)) { printf("读取文件“%s”失败\n", FileNameInPut); return; } sha1_final (&ctx); fclose (fp); for ( i=0; i < 20; i++) { printf("%02x",ctx.buf[i]); } }
适合程序中调用的返回值方式:
/*获取文件的SHA1值,如果发生错误则将错误信息写入outError * FileNameInPut:文件路径 * outSHA1:SHA1输出变量 * outError:错误信息输出变量 * returns:outSHA1 */ char *GetFileSHA1(char *FileNameInPut, char *outSHA1, char *outError) { if(FileNameInPut==NULL) { if (outError != NULL) { sprintf(outError, "%s", "FileNameInPut Is NULL"); } return outSHA1; } FILE *fp; char buffer[4096]; size_t n; SHA1_CONTEXT ctx; int i; fopen_s (&fp, FileNameInPut, "rb"); if (!fp) { if (outError != NULL) { sprintf(outError, "打开文件“%s”失败\n", FileNameInPut); } return outSHA1; } sha1_init (&ctx); while ( (n = fread (buffer, 1, sizeof buffer, fp))) sha1_write (&ctx, (unsigned char *)buffer, n); if (ferror (fp)) { if (outError != NULL) { sprintf(outError, "读取文件“%s”失败\n", FileNameInPut); } return outSHA1; } sha1_final (&ctx); fclose (fp); for ( i=0; i < 20; i++) { sprintf(outSHA1 + 2*i, "%02x", (unsigned char)ctx.buf[i]); } outSHA1[2*i] = ‘\0‘; return outSHA1; }水平有限,此方法只是简单的实现,还有些问题没有解决,希望高手指点一二,小弟不胜感激!
用法示例:
//用法实例: int main (int argc, char **argv) { GetFileSHA1(*(argv+1)); printf("\r\n"); char sha1[41] = { 0 }; char eror[256] = { 0 }; printf("%s\r\n", GetFileSHA1(*(argv+1), sha1, NULL)); if (strlen(eror) != 0) { printf("获取SHA1发生错误:%s\r\n", eror); } printf("%s\r\n", GetFileSHA1(*(argv+1), sha1, eror)); if (strlen(eror) != 0) { printf("获取SHA1发生错误:%s\r\n", eror); } getchar(); return 0; }
命令提示符下用法:
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