速速收藏！纯C实现的MD5哈希校验算法~！

只有一个函数：
void MD5(const void* buf, unsigned int len, unsigned char output[16]);

讯享网

在线验证网站：https://www.sojson.com/md5/

头文件

/ * \file md5.h * * \brief MD5 message digest algorithm (hash function) */ #ifndef MD5_H__ #define MD5_H__ #ifdef __cplusplus extern "C" { 
    #endif void MD5(const void* buf, unsigned int len, unsigned char output[16]); #ifdef __cplusplus } #endif #endif 

源文件

讯享网/ * \file md5.c * * \brief MD5 message digest algorithm (hash function) */ #include <stdio.h> #include <stdint.h> #include <string.h> #include "md5.h" typedef struct { 
    uint32_t total[2]; /*!< number of bytes processed */ uint32_t state[4]; /*!< intermediate digest state */ unsigned char buffer[64]; /*!< data block being processed */ }md5_context; /* * 32-bit integer manipulation macros (little endian) */ #define GET_UINT32_LE(n,b,i) \ { 
      \ (n) = ( (uint32_t) (b)[(i) ] ) \ | ( (uint32_t) (b)[(i) + 1] << 8 ) \ | ( (uint32_t) (b)[(i) + 2] << 16 ) \ | ( (uint32_t) (b)[(i) + 3] << 24 ); \ } #define PUT_UINT32_LE(n,b,i) \ { 
      \ (b)[(i) ] = (unsigned char) ( ( (n) ) & 0xFF ); \ (b)[(i) + 1] = (unsigned char) ( ( (n) >> 8 ) & 0xFF ); \ (b)[(i) + 2] = (unsigned char) ( ( (n) >> 16 ) & 0xFF ); \ (b)[(i) + 3] = (unsigned char) ( ( (n) >> 24 ) & 0xFF ); \ } void md5_internal_process(md5_context *ctx, const unsigned char data[64]) { 
    uint32_t X[16], A, B, C, D; GET_UINT32_LE( X[ 0], data, 0 ); GET_UINT32_LE( X[ 1], data, 4 ); GET_UINT32_LE( X[ 2], data, 8 ); GET_UINT32_LE( X[ 3], data, 12 ); GET_UINT32_LE( X[ 4], data, 16 ); GET_UINT32_LE( X[ 5], data, 20 ); GET_UINT32_LE( X[ 6], data, 24 ); GET_UINT32_LE( X[ 7], data, 28 ); GET_UINT32_LE( X[ 8], data, 32 ); GET_UINT32_LE( X[ 9], data, 36 ); GET_UINT32_LE( X[10], data, 40 ); GET_UINT32_LE( X[11], data, 44 ); GET_UINT32_LE( X[12], data, 48 ); GET_UINT32_LE( X[13], data, 52 ); GET_UINT32_LE( X[14], data, 56 ); GET_UINT32_LE( X[15], data, 60 ); #define S(x,n) \ ( ( (x) << (n) ) | ( ( (x) & 0xFFFFFFFF) >> ( 32 - (n) ) ) ) #define P(a,b,c,d,k,s,t) \ do \ { 
      \ (a) += F((b),(c),(d)) + X[(k)] + (t); \ (a) = S((a),(s)) + (b); \ } while( 0 ) A = ctx->state[0]; B = ctx->state[1]; C = ctx->state[2]; D = ctx->state[3]; #define F(x,y,z) ((z) ^ ((x) & ((y) ^ (z)))) P( A, B, C, D, 0, 7, 0xD76AA478 ); P( D, A, B, C, 1, 12, 0xE8C7B756 ); P( C, D, A, B, 2, 17, 0xDB ); P( B, C, D, A, 3, 22, 0xC1BDCEEE ); P( A, B, C, D, 4, 7, 0xF57C0FAF ); P( D, A, B, C, 5, 12, 0x4787C62A ); P( C, D, A, B, 6, 17, 0xA ); P( B, C, D, A, 7, 22, 0xFD ); P( A, B, C, D, 8, 7, 0xD8 ); P( D, A, B, C, 9, 12, 0x8B44F7AF ); P( C, D, A, B, 10, 17, 0xFFFF5BB1 ); P( B, C, D, A, 11, 22, 0x895CD7BE ); P( A, B, C, D, 12, 7, 0x6B ); P( D, A, B, C, 13, 12, 0xFD ); P( C, D, A, B, 14, 17, 0xAE ); P( B, C, D, A, 15, 22, 0x49B40821 ); #undef F #define F(x,y,z) ((y) ^ ((z) & ((x) ^ (y)))) P( A, B, C, D, 1, 5, 0xF61E2562 ); P( D, A, B, C, 6, 9, 0xC040B340 ); P( C, D, A, B, 11, 14, 0x265E5A51 ); P( B, C, D, A, 0, 20, 0xE9B6C7AA ); P( A, B, C, D, 5, 5, 0xD62F105D ); P( D, A, B, C, 10, 9, 0x0 ); P( C, D, A, B, 15, 14, 0xD8A1E681 ); P( B, C, D, A, 4, 20, 0xE7D3FBC8 ); P( A, B, C, D, 9, 5, 0x21E1CDE6 ); P( D, A, B, C, 14, 9, 0xC33707D6 ); P( C, D, A, B, 3, 14, 0xF4D50D87 ); P( B, C, D, A, 8, 20, 0x455A14ED ); P( A, B, C, D, 13, 5, 0xA9E3E905 ); P( D, A, B, C, 2, 9, 0xFCEFA3F8 ); P( C, D, A, B, 7, 14, 0x676F02D9 ); P( B, C, D, A, 12, 20, 0x8D2A4C8A ); #undef F #define F(x,y,z) ((x) ^ (y) ^ (z)) P( A, B, C, D, 5, 4, 0xFFFA3942 ); P( D, A, B, C, 8, 11, 0x8771F681 ); P( C, D, A, B, 11, 16, 0x6D9D6122 ); P( B, C, D, A, 14, 23, 0xFDE5380C ); P( A, B, C, D, 1, 4, 0xA4BEEA44 ); P( D, A, B, C, 4, 11, 0x4BDECFA9 ); P( C, D, A, B, 7, 16, 0xF6BB4B60 ); P( B, C, D, A, 10, 23, 0xBEBFBC70 ); P( A, B, C, D, 13, 4, 0x289B7EC6 ); P( D, A, B, C, 0, 11, 0xEAA127FA ); P( C, D, A, B, 3, 16, 0xD4EF3085 ); P( B, C, D, A, 6, 23, 0x04881D05 ); P( A, B, C, D, 9, 4, 0xD9D4D039 ); P( D, A, B, C, 12, 11, 0xE6DB99E5 ); P( C, D, A, B, 15, 16, 0x1FA27CF8 ); P( B, C, D, A, 2, 23, 0xC4AC5665 ); #undef F #define F(x,y,z) ((y) ^ ((x) | ~(z))) P( A, B, C, D, 0, 6, 0xF ); P( D, A, B, C, 7, 10, 0x432AFF97 ); P( C, D, A, B, 14, 15, 0xAB9423A7 ); P( B, C, D, A, 5, 21, 0xFC93A039 ); P( A, B, C, D, 12, 6, 0x655B59C3 ); P( D, A, B, C, 3, 10, 0x8F0CCC92 ); P( C, D, A, B, 10, 15, 0xFFEFF47D ); P( B, C, D, A, 1, 21, 0x85845DD1 ); P( A, B, C, D, 8, 6, 0x6FA87E4F ); P( D, A, B, C, 15, 10, 0xFE2CE6E0 ); P( C, D, A, B, 6, 15, 0xA ); P( B, C, D, A, 13, 21, 0x4E0811A1 ); P( A, B, C, D, 4, 6, 0xF7537E82 ); P( D, A, B, C, 11, 10, 0xBD3AF235 ); P( C, D, A, B, 2, 15, 0x2AD7D2BB ); P( B, C, D, A, 9, 21, 0xEB86D391 ); #undef F ctx->state[0] += A; ctx->state[1] += B; ctx->state[2] += C; ctx->state[3] += D; } /* * MD5 process buffer */ static void md5_update( md5_context *ctx, const unsigned char *input, size_t ilen) { 
    size_t fill; uint32_t left; if( ilen == 0 ) return; left = ctx->total[0] & 0x3F; fill = 64 - left; ctx->total[0] += (uint32_t) ilen; ctx->total[0] &= 0xFFFFFFFF; if( ctx->total[0] < (uint32_t) ilen ) ctx->total[1]++; if( left && ilen >= fill ) { 
    memcpy( (void *) (ctx->buffer + left), input, fill ); md5_internal_process( ctx, ctx->buffer ); input += fill; ilen -= fill; left = 0; } while( ilen >= 64 ) { 
    md5_internal_process( ctx, input ); input += 64; ilen -= 64; } if( ilen > 0 ) { 
    memcpy( (void *) (ctx->buffer + left), input, ilen ); } } /* * MD5 final digest */ static void md5_finish( md5_context *ctx, unsigned char output[16]) { 
    uint32_t used; uint32_t high, low; /* * Add padding: 0x80 then 0x00 until 8 bytes remain for the length */ used = ctx->total[0] & 0x3F; ctx->buffer[used++] = 0x80; if( used <= 56 ) { 
    /* Enough room for padding + length in current block */ memset( ctx->buffer + used, 0, 56 - used ); } else { 
    /* We'll need an extra block */ memset( ctx->buffer + used, 0, 64 - used ); md5_internal_process( ctx, ctx->buffer ); memset( ctx->buffer, 0, 56 ); } /* * Add message length */ high = ( ctx->total[0] >> 29 ) | ( ctx->total[1] << 3 ); low = ( ctx->total[0] << 3 ); PUT_UINT32_LE( low, ctx->buffer, 56 ); PUT_UINT32_LE( high, ctx->buffer, 60 ); md5_internal_process( ctx, ctx->buffer ); /* * Output final state */ PUT_UINT32_LE( ctx->state[0], output, 0 ); PUT_UINT32_LE( ctx->state[1], output, 4 ); PUT_UINT32_LE( ctx->state[2], output, 8 ); PUT_UINT32_LE( ctx->state[3], output, 12 ); } void MD5(const void* buf, unsigned int len, unsigned char output[16]) { 
    md5_context ctx = { 
   0}; ctx.total[0] = 0; ctx.total[1] = 0; ctx.state[0] = 0x; ctx.state[1] = 0xEFCDAB89; ctx.state[2] = 0x98BADCFE; ctx.state[3] = 0x; md5_update(&ctx, (unsigned char *)buf, len); md5_finish(&ctx, output); } #if 0 #include <stdio.h> #include <stdlib.h> #include "md5.h" /* verify online: https://www.sojson.com/md5/ testdata:helloworld md5(hex):cee76d16b6c243c1cd7c7ecc677de87d */ int main(void) { 
    const char* testdata = "helloworld"; uint8_t md5[16]; MD5(testdata, strlen(testdata), md5); printf("testdata:%s\n", testdata); printf("md5(hex):"); for(int i = 0; i < 16; i++) { 
    printf("%02x", md5[i]); } printf("\n"); return 0; } #endif