c语言md5算法_C语言编译器软件[通俗易懂]

C语言MD5计算库

介绍

计算16字节128位md5码。

开源

• github上的项目地址
• gitee上的项目地址

API

// MD5 len
#define MD5_LEN 16

// MD5Calc calc md5
// out is md5 result.Notice out array size is greater than 16
void MD5Calc(uint8_t* data, int len, uint8_t* out);

测试

测试框架使用的是适合于嵌入式系统的C语言单元测试框架:Scunit
使用cip可以安装依赖的包:cip：C/C++包管理工具

#include <stdio.h>
#include "md5.h"
#include "scunit.h"

static void testMD5(void);

int main() { 
   
    ScunitLoad((ScunitPrintFunc)printf);
        ScunitAddSuite("test crc16");
        ScunitAddTest("testMD5", testMD5);
    return 0;
}

static void testMD5(void) { 
   
    uint8_t out[16] = { 
   0};
    char* str = "hellojdh";
    MD5Calc((uint8_t*)str, (int)strlen(str), out);

    // de56197c9dd72b188c0709a239c9a390
    uint8_t result[32] = { 
   0xde, 0x56, 0x19, 0x7c, 0x9d, 0xd7, 0x2b, 0x18, 0x8c, 0x07, 0x09, 0xa2, 0x39, 0xc9, 0xa3, 0x90};
    ScunitAssert(memcmp(out, result, 16) == 0, "1");
}

输出:

Suite:test md5
-------------------->case:testMD5 begin
testMD5 tag:1 SCUNIT_ASSERT pass
-------------------->case:testMD5 end

源码

最新代码请参考github/gitee仓库。

md5.h

// Copyright 2020-2021 The jdh99 Authors. All rights reserved.
// calc md5
// Authors: jdh99 <jdh821@163.com>

#ifndef MD5_H
#define MD5_H

#include <stdint.h>

// MD5 len
#define MD5_LEN 16

// MD5Calc calc md5
// out is md5 result.Notice out array size is greater than 16
void MD5Calc(uint8_t* data, int len, uint8_t* out);

#endif

md5.c

// Copyright 2020-2021 The jdh99 Authors. All rights reserved.
// calc md5
// Authors: jdh99 <jdh821@163.com>

#include "md5.h"
#include <string.h>

#define F(x,y,z) ((x & y) | (~x & z))
#define G(x,y,z) ((x & z) | (y & ~z))
#define H(x,y,z) (x^y^z)
#define I(x,y,z) (y ^ (x | ~z))
#define ROTATE_LEFT(x,n) ((x << n) | (x >> (32-n)))
#define FF(a,b,c,d,x,s,ac) \ { \ a += F(b,c,d) + x + ac; \ a = ROTATE_LEFT(a,s); \ a += b; \ }
#define GG(a,b,c,d,x,s,ac) \ { \ a += G(b,c,d) + x + ac; \ a = ROTATE_LEFT(a,s); \ a += b; \ }
#define HH(a,b,c,d,x,s,ac) \ { \ a += H(b,c,d) + x + ac; \ a = ROTATE_LEFT(a,s); \ a += b; \ }
#define II(a,b,c,d,x,s,ac) \ { \ a += I(b,c,d) + x + ac; \ a = ROTATE_LEFT(a,s); \ a += b; \ }

typedef struct
{ 
   
    unsigned int count[2];
    unsigned int state[4];
    unsigned char buffer[64];
} MD5_CTX;

static MD5_CTX md5;

static void MD5Init(MD5_CTX* context);
static void MD5Update(MD5_CTX* context, unsigned char* input, unsigned int inputlen);
static void MD5Final(MD5_CTX* context, unsigned char digest[16]);
static void MD5Transform(unsigned int state[4], unsigned char block[64]);
static void MD5Encode(unsigned char* output, unsigned int* input, unsigned int len);
static void MD5Decode(unsigned int* output, unsigned char* input, unsigned int len);

static unsigned char PADDING[] = { 
   
    0x80,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
    0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
    0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
    0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
};

// MD5Calc calc md5
// out is md5 result.Notice out array size is greater than 16
void MD5Calc(uint8_t* data, int len, uint8_t* out) { 
   
    MD5Init(&md5);
    MD5Update(&md5, data, (unsigned int)len);
    MD5Final(&md5, out);
}

static void MD5Init(MD5_CTX* context) { 
   
     context->count[0] = 0;
     context->count[1] = 0;
     context->state[0] = 0x67452301;
     context->state[1] = 0xEFCDAB89;
     context->state[2] = 0x98BADCFE;
     context->state[3] = 0x10325476;
}

static void MD5Update(MD5_CTX* context, unsigned char *input, unsigned int inputlen) { 
   
    unsigned int i = 0, index = 0, partlen = 0;
    index = (context->count[0] >> 3) & 0x3F;
    partlen = 64 - index;
    context->count[0] += inputlen << 3;
    if(context->count[0] < (inputlen << 3)) { 
   
       context->count[1]++;
    }
    context->count[1] += inputlen >> 29;

    if(inputlen >= partlen) { 
   
       memcpy(&context->buffer[index], input, partlen);
       MD5Transform(context->state,context->buffer);
       for(i = partlen;i+64 <= inputlen;i+=64) { 
   
           MD5Transform(context->state,&input[i]);
       }
       index = 0;
    } else { 
   
        i = 0;
    }
    memcpy(&context->buffer[index], &input[i], inputlen - i);
}

static void MD5Final(MD5_CTX* context, unsigned char digest[16]) { 
   
    unsigned int index = 0, padlen = 0;
    unsigned char bits[8];
    index = (context->count[0] >> 3) & 0x3F;
    padlen = (index < 56)?(56-index):(120-index);
    MD5Encode(bits,context->count,8);
    MD5Update(context,PADDING,padlen);
    MD5Update(context,bits,8);
    MD5Encode(digest,context->state,16);
}

static void MD5Encode(unsigned char* output, unsigned int* input, unsigned int len) { 
   
    unsigned int i = 0,j = 0;
    while(j < len) { 
   
         output[j] = input[i] & 0xFF;
         output[j+1] = (input[i] >> 8) & 0xFF;
         output[j+2] = (input[i] >> 16) & 0xFF;
         output[j+3] = (input[i] >> 24) & 0xFF;
         i++;
         j+=4;
    }
}

static void MD5Decode(unsigned int* output, unsigned char* input, unsigned int len) { 
   
     unsigned int i = 0,j = 0;
     while(j < len) { 
   
           output[i] = (input[j]) |
                       (input[j+1] << 8) |
                       (input[j+2] << 16) |
                       (input[j+3] << 24);
           i++;
           j+=4;
     }
}

static void MD5Transform(unsigned int state[4], unsigned char block[64]) { 
   
     unsigned int a = state[0];
     unsigned int b = state[1];
     unsigned int c = state[2];
     unsigned int d = state[3];
     unsigned int x[64];

     MD5Decode(x,block,64);
     FF(a, b, c, d, x[ 0], 7, 0xd76aa478); /* 1 */
     FF(d, a, b, c, x[ 1], 12, 0xe8c7b756); /* 2 */
     FF(c, d, a, b, x[ 2], 17, 0x242070db); /* 3 */
     FF(b, c, d, a, x[ 3], 22, 0xc1bdceee); /* 4 */
     FF(a, b, c, d, x[ 4], 7, 0xf57c0faf); /* 5 */
     FF(d, a, b, c, x[ 5], 12, 0x4787c62a); /* 6 */
     FF(c, d, a, b, x[ 6], 17, 0xa8304613); /* 7 */
     FF(b, c, d, a, x[ 7], 22, 0xfd469501); /* 8 */
     FF(a, b, c, d, x[ 8], 7, 0x698098d8); /* 9 */
     FF(d, a, b, c, x[ 9], 12, 0x8b44f7af); /* 10 */
     FF(c, d, a, b, x[10], 17, 0xffff5bb1); /* 11 */
     FF(b, c, d, a, x[11], 22, 0x895cd7be); /* 12 */
     FF(a, b, c, d, x[12], 7, 0x6b901122); /* 13 */
     FF(d, a, b, c, x[13], 12, 0xfd987193); /* 14 */
     FF(c, d, a, b, x[14], 17, 0xa679438e); /* 15 */
     FF(b, c, d, a, x[15], 22, 0x49b40821); /* 16 */

     // Round 2
     GG(a, b, c, d, x[ 1], 5, 0xf61e2562); /* 17 */
     GG(d, a, b, c, x[ 6], 9, 0xc040b340); /* 18 */
     GG(c, d, a, b, x[11], 14, 0x265e5a51); /* 19 */
     GG(b, c, d, a, x[ 0], 20, 0xe9b6c7aa); /* 20 */
     GG(a, b, c, d, x[ 5], 5, 0xd62f105d); /* 21 */
     GG(d, a, b, c, x[10], 9,  0x2441453); /* 22 */
     GG(c, d, a, b, x[15], 14, 0xd8a1e681); /* 23 */
     GG(b, c, d, a, x[ 4], 20, 0xe7d3fbc8); /* 24 */
     GG(a, b, c, d, x[ 9], 5, 0x21e1cde6); /* 25 */
     GG(d, a, b, c, x[14], 9, 0xc33707d6); /* 26 */
     GG(c, d, a, b, x[ 3], 14, 0xf4d50d87); /* 27 */
     GG(b, c, d, a, x[ 8], 20, 0x455a14ed); /* 28 */
     GG(a, b, c, d, x[13], 5, 0xa9e3e905); /* 29 */
     GG(d, a, b, c, x[ 2], 9, 0xfcefa3f8); /* 30 */
     GG(c, d, a, b, x[ 7], 14, 0x676f02d9); /* 31 */
     GG(b, c, d, a, x[12], 20, 0x8d2a4c8a); /* 32 */

     // Round 3
     HH(a, b, c, d, x[ 5], 4, 0xfffa3942); /* 33 */
     HH(d, a, b, c, x[ 8], 11, 0x8771f681); /* 34 */
     HH(c, d, a, b, x[11], 16, 0x6d9d6122); /* 35 */
     HH(b, c, d, a, x[14], 23, 0xfde5380c); /* 36 */
     HH(a, b, c, d, x[ 1], 4, 0xa4beea44); /* 37 */
     HH(d, a, b, c, x[ 4], 11, 0x4bdecfa9); /* 38 */
     HH(c, d, a, b, x[ 7], 16, 0xf6bb4b60); /* 39 */
     HH(b, c, d, a, x[10], 23, 0xbebfbc70); /* 40 */
     HH(a, b, c, d, x[13], 4, 0x289b7ec6); /* 41 */
     HH(d, a, b, c, x[ 0], 11, 0xeaa127fa); /* 42 */
     HH(c, d, a, b, x[ 3], 16, 0xd4ef3085); /* 43 */
     HH(b, c, d, a, x[ 6], 23,  0x4881d05); /* 44 */
     HH(a, b, c, d, x[ 9], 4, 0xd9d4d039); /* 45 */
     HH(d, a, b, c, x[12], 11, 0xe6db99e5); /* 46 */
     HH(c, d, a, b, x[15], 16, 0x1fa27cf8); /* 47 */
     HH(b, c, d, a, x[ 2], 23, 0xc4ac5665); /* 48 */

     // Round 4
     II(a, b, c, d, x[ 0], 6, 0xf4292244); /* 49 */
     II(d, a, b, c, x[ 7], 10, 0x432aff97); /* 50 */
     II(c, d, a, b, x[14], 15, 0xab9423a7); /* 51 */
     II(b, c, d, a, x[ 5], 21, 0xfc93a039); /* 52 */
     II(a, b, c, d, x[12], 6, 0x655b59c3); /* 53 */
     II(d, a, b, c, x[ 3], 10, 0x8f0ccc92); /* 54 */
     II(c, d, a, b, x[10], 15, 0xffeff47d); /* 55 */
     II(b, c, d, a, x[ 1], 21, 0x85845dd1); /* 56 */
     II(a, b, c, d, x[ 8], 6, 0x6fa87e4f); /* 57 */
     II(d, a, b, c, x[15], 10, 0xfe2ce6e0); /* 58 */
     II(c, d, a, b, x[ 6], 15, 0xa3014314); /* 59 */
     II(b, c, d, a, x[13], 21, 0x4e0811a1); /* 60 */
     II(a, b, c, d, x[ 4], 6, 0xf7537e82); /* 61 */
     II(d, a, b, c, x[11], 10, 0xbd3af235); /* 62 */
     II(c, d, a, b, x[ 2], 15, 0x2ad7d2bb); /* 63 */
     II(b, c, d, a, x[ 9], 21, 0xeb86d391); /* 64 */

     state[0] += a;
     state[1] += b;
     state[2] += c;
     state[3] += d;
}

参考链接

• c语言：md5函数
• MD5 Algorithm

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