C语言 MD5加密

main.cpp

#include <stdio.h>

#include <string.h>

#include <stdlib.h>

#include "md5.c"

int main(int argc, char* argv[])

{

int i

unsigned char encrypt[] = "admin"//21232f297a57a5a743894a0e4a801fc3

unsigned char decrypt[16]

MD5_CTX md5

MD5Init(&md5)

MD5Update(&md5, encrypt, strlen((char*)encrypt))

MD5Final(&md5, decrypt)

printf("加密前:%s\n加密后:", encrypt)

for (i = 0i <16i++)

{

printf("%02x", decrypt[i])

}

getchar()

return 0

}

md5.c

#include <memory.h>

#include "md5.h"

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 }

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

}

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 = partleni + 64 <= inputleni += 64)

            MD5Transform(context->state, &input[i])

        index = 0

    }

    else

    {

        i = 0

    }

    memcpy(&context->buffer[index], &input[i], inputlen - i)

}

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)

}

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

    }

}

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

    }

}

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

}

md5.h

#ifndef MD5_H

#define MD5_H

typedef struct

{

    unsigned int count[2]

    unsigned int state[4]

    unsigned char buffer[64]

}MD5_CTX

#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\

          }

void MD5Init(MD5_CTX* context)

void MD5Update(MD5_CTX* context, unsigned char* input, unsigned int inputlen)

void MD5Final(MD5_CTX* context, unsigned char digest[16])

void MD5Transform(unsigned int state[4], unsigned char block[64])

void MD5Encode(unsigned char* output, unsigned int* input, unsigned int len)

void MD5Decode(unsigned int* output, unsigned char* input, unsigned int len)

#endif

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#if defined(__APPLE__)

#  define COMMON_DIGEST_FOR_OPENSSL

#  include <CommonCrypto/CommonDigest.h>

#  define SHA1 CC_SHA1

#else

#  include <openssl/md5.h>

#endif

// 这是我自己写的函数，用于计算MD5

// 参数 str：要转换的字符串

// 参数 lengthL: 字符串的长度 可以用 strlen(str) 直接获取参数str的长度

// 返回值：MD5字符串

char *str2md5(const char * str, int length) {

    int n

    MD5_CTX c

    unsigned char digest[16]

    char *out = (char*)malloc(33)

    MD5_Init(&c)

    while (length > 0) {

        if (length > 512) {

            MD5_Update(&c, str, 512)

        } else {

            MD5_Update(&c, str, length)

        }

        length -= 512

        str += 512

    }

    MD5_Final(digest, &c)

    for (n = 0 n < 16 ++n) {

        snprintf(&(out[n*2]), 16*2, "%02x", (unsigned int)digest[n])

    }

    return out

}

    int main(int argc, char **argv) {

        char *output = str2md5("hello", strlen("hello"))

        

        printf("%s\n", output)

        // 上面会输出 hello的MD5字符串：

        // 5d41402abc4b2a76b9719d911017c592

        free(output)

        return 0

    }

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