请教MD5算法 用C语言实现

#include stdio.h

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#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;

}

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 = 0; i 16; i++)

{

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 = partlen; i + 64 = inputlen; i += 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

VS2013中c语言md5加密函数怎么调用?

1、主要就是调用库函数，MD5加密说到底也是函数计算，没有什么思路的问题，了解md5的发明算法，本质是一个数学问题。

2、例程：

#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

源文件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 = partlen;i+64 = inputlen;i+=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 */

如何对字符串进行MD5加密,用C语言实现,给出源代码和加密函数

#include stdio.h

#define S11 7

#define S12 12

#define S13 17

#define S14 22

#define S21 5

#define S22 9

#define S23 14

#define S24 20

#define S31 4

#define S32 11

#define S33 16

#define S34 23

#define S41 6

#define S42 10

#define S43 15

#define S44 21

#define R_memset(x, y, z) memset(x, y, z)

#define R_memcpy(x, y, z) memcpy(x, y, z)

#define R_memcmp(x, y, z) memcmp(x, y, z)

typedef unsigned long UINT4;

typedef unsigned char *POINTER;

typedef struct {

/*四个32bits数,用于存放最终计算得到的消息摘要.当消息长度512bits时,也用于存放每个512bits的中间结果*/

UINT4 state[4];

/*存储原始信息的bits数长度,不包括填充的bits,最长为2^64 bits*/

UINT4 count[2];

/*存放输入的信息的缓冲区,512bits*/

unsigned char buffer[64];

} MD5_CTX;

static void MD5Transform(UINT4[4], unsigned char[64]);

static void Encode(unsigned char *, UINT4 *, unsigned int);

static void Decode(UINT4 *, unsigned char *, unsigned int);

/*

用于bits填充的缓冲区,当欲加密的信息的bits数被512除其余数为448时,需要填充的bits的最大值为512=64*8*/

static unsigned char PADDING[64] = {

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

};

/*接下来的这几个宏定义是md5算法规定的,就是对信息进行md5加密都要做的运算*/

#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) + (UINT4)(ac);\

(a) = ROTATE_LEFT ((a), (s));\

(a) += (b);\

}

#define GG(a, b, c, d, x, s, ac) {\

(a) += G ((b), (c), (d)) + (x) + (UINT4)(ac);\

(a) = ROTATE_LEFT ((a), (s));\

(a) += (b);\

}

#define HH(a, b, c, d, x, s, ac) {\

(a) += H ((b), (c), (d)) + (x) + (UINT4)(ac);\

(a) = ROTATE_LEFT ((a), (s));\

(a) += (b);\

}

#define II(a, b, c, d, x, s, ac) {\

(a) += I ((b), (c), (d)) + (x) + (UINT4)(ac);\

(a) = ROTATE_LEFT ((a), (s));\

(a) += (b);\

}

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