md5c语言加密算法

1. 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

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*/

2. 浠涔堟槸md5锷犲瘑

浠庝簨缃戠粶瀹夊叏杩欎竴琛屼笟镄勪汉閮界煡阆掳纴鎴戜滑锅氭笚阃忔祴璇曟椂缁忓父浼氶亣鍒伴渶瑕佽В瀵嗙殑Md5瀵嗘枃銆备负浜呜兘澶熸彁鍗囨晥鐜囷纴鎴戜滑鍙浠ュ湪缃戜笂镓句竴浜涜兘澶熷湪绾縨d5瑙ｅ瘑镄勭绣绔欍备笅闱㈢粰澶у跺垎浜锲藉唴甯哥敤镄勫嚑涓鍏嶈垂MD5鍦ㄧ嚎瑙ｅ瘑缃戠珯銆

涓銆丮D5鍦ㄧ嚎锷犲瘑瑙ｅ瘑

阍埚筸d5绛夊叏鐞冮氱敤鍏寮镄勫姞瀵嗙畻娉曡繘琛屽弽钖戞煡璇锛屽缓绔嬩简瀵嗘枃瀵瑰簲镆ヨ㈡暟鎹搴掳纴MD5锷犲瘑瑙ｅ瘑骞冲彴鍙镆ヨ㈠緢澶氩嶆潅瀵嗘枃锛屾敮鎸佸氱岖畻娉曪纴瀹炴椂镆ヨ㈣板綍瓒呰繃24涓囦嚎𨱒★纴鍏卞崰鐢160T纭鐩桡纴鎴愬姛鐜95%浠ヤ笂銆傝繖涓缃戠珯锲介楅厤鍐呭緢澶氢汉鍦ㄤ娇鐢锛屽洜涓哄畠鏄鍏嶈垂镄勚傚傛灉鍦╩d5涓婅В瀵嗕笉浜嗙殑瀵嗘枃鍦ㄥ叾浠栬В瀹㈢绣绔欎篃锘烘湰娌℃垙浜嗐

3. 求生成MD5码的c或c++代码

自己用C语言写的简单的MD5算法实现。

#include <stdio.h>
#include <stdlib.h>
#include <memory.h>
#include <math.h>

typedef unsigned char BYTE;
typedef unsigned int UINT;
typedef UINT MD5_SUB_ARRAY[16];
typedef UINT MD5_TRANSORM_FUNC(UINT,UINT,UINT);
typedef struct
{
UINT a;
UINT b;
UINT c;
UINT d;
MD5_SUB_ARRAY sub_array;
}MD5_TRANSFORM_PARAM;

const double MAX_INT = (double)0xFFFFFFFF + 1.0;

const UINT MD5_TRANSFORM_MATRIX[4][16][3] =
{

{
{ 0, 7, 1}, { 1,12, 2}, { 2,17, 3}, { 3,22, 4},
{ 4, 7, 5}, { 5,12, 6}, { 6,17, 7}, { 7,22, 8},
{ 8, 7, 9}, { 9,12,10}, {10,17,11}, {11,22,12},
{12, 7,13}, {13,12,14}, {14,17,15}, {15,22,16},
},

{
{ 1, 5,17}, { 6, 9,18}, {11,14,19}, { 0,20,20},
{ 5, 5,21}, {10, 9,22}, {15,14,23}, { 4,20,24},
{ 9, 5,25}, {14, 9,26}, { 3,14,27}, { 8,20,28},
{13, 5,29}, { 2, 9,30}, { 7,14,31}, {12,20,32},
},

{
{5, 4, 33}, { 8,11,34}, {11,16,35},{14, 23,36},
{1, 4, 37}, { 4,11,38}, { 7,16,39},{10, 23,40},
{13,4, 41}, { 0,11,42}, { 3,16,43},{ 6, 23,44},
{9, 4, 45}, {12,11,46}, {15,16,47},{ 2, 23,48},
},

{
{ 0,6,49}, { 7,10,50}, {14,15,51},{ 5, 21,52},
{12,6,53}, { 3,10,54}, {10,15,55},{ 1, 21,56},
{ 8,6,57}, {15,10,58}, { 6,15,59},{13, 21,60},
{ 4,6,61}, {11,10,62}, { 2,15,63},{ 9, 21,64},
},
};

static UINT MD5_TRANSFORM_ARRAY[65];

void MD5_Init()
{
int x;
for(x = 1; x <= 64; x++)
{
MD5_TRANSFORM_ARRAY[x] = (UINT)(MAX_INT * fabs(sin(x)));
}
}

UINT F(UINT x,UINT y,UINT z)
{
return ((x & y) | ((~x) & z));
}

UINT G(UINT x,UINT y,UINT z)
{
return ((x & z) | (y & (~z)));
}

UINT H(UINT x,UINT y,UINT z)
{
return (x ^ y ^ z);
}

UINT I(UINT x,UINT y,UINT z)
{
return (y ^ (x | (~z)));
}

BYTE* MD5_prepare_data(const BYTE* data,int len,int* new_len)
{
int rest,fill,size;
BYTE* new_data;
UINT bit_len;

// (1) 字节补齐
rest = len % 56;
if (rest <= 56) fill = 56 - rest;
else fill = (64 - rest) + 56;

new_data = (BYTE*)malloc(len + fill + 8);
if (NULL == new_data) return NULL;

if (len > 0) memcpy(new_data,data,len);
if (fill > 0) memset(new_data + len,0x80,1);
if (fill > 1) memset(new_data + len + 1,0,fill - 1);

size = fill + len;

// (2) 附加数据的比特长度
bit_len = len * 8;
// (64位二进制数表示的)比特长度的低32位
memset(new_data + size + 0,(bit_len & 0x000000FF), 1);
memset(new_data + size + 1,(bit_len & 0x0000FF00) >> 8, 1);
memset(new_data + size + 2,(bit_len & 0x00FF0000) >> 16,1);
memset(new_data + size + 3,(bit_len & 0xFF000000) >> 24,1);
// 不考虑比特长度超出32位无符号数表示范围,所以高32位总是0
memset(new_data + size + 4,0,4);

*new_len = size + 8;

return new_data;
}

void MD5_transform(MD5_TRANSFORM_PARAM* param,int ring,MD5_TRANSORM_FUNC func)
{
UINT a,b,c,d,s,k,i;
UINT abcd[4];
UINT *X,*T;
int index;

abcd[0] = param->a;
abcd[1] = param->b;
abcd[2] = param->c;
abcd[3] = param->d;
X = param->sub_array;
T = MD5_TRANSFORM_ARRAY;

for(index = 0; index < 16; index++)
{
a = abcd[(3 * index + 0) % 4];
b = abcd[(3 * index + 1) % 4];
c = abcd[(3 * index + 2) % 4];
d = abcd[(3 * index + 3) % 4];

k = MD5_TRANSFORM_MATRIX[ring][index][0];
s = MD5_TRANSFORM_MATRIX[ring][index][1];
i = MD5_TRANSFORM_MATRIX[ring][index][2];

a = a + func(b,c,d) + X[k] + T[i];
a = ( a << s) | ( a >> (32 - s)); // 循环左移
a = a + b;

abcd[(3 * index + 0) % 4] = a;
}

param->a = abcd[0];
param->b = abcd[1];
param->c = abcd[2];
param->d = abcd[3];
}

int MD5(const BYTE* data,int len)
{
int x,y,new_len;
MD5_TRANSFORM_PARAM param;
UINT AA,BB,CC,DD;
BYTE* buf;

MD5_Init();

buf = MD5_prepare_data(data,len,&new_len);
if (buf == NULL) return -1;

AA = 0x67452301;
BB = 0xefcdab89;
CC = 0x98badcfe;
DD = 0x10325476;

for(x = 0; x < new_len / 64; x++)
{
param.a = AA;
param.b = BB;
param.c = CC;
param.d = DD;

for(y = 0; y < 16; y++)
{
param.sub_array[y] = buf[64 * x + 4 * y + 0];
param.sub_array[y] += buf[64 * x + 4 * y + 1] << 8;
param.sub_array[y] += buf[64 * x + 4 * y + 2] << 16;
param.sub_array[y] += buf[64 * x + 4 * y + 3] << 24;
}
MD5_transform(¶m,0,F);
MD5_transform(¶m,1,G);
MD5_transform(¶m,2,H);
MD5_transform(¶m,3,I);

AA += param.a;
BB += param.b;
CC += param.c;
DD += param.d;
}

printf("MD5(\"%s\")=",data);

printf("%02X%02X%02X%02X",
(AA & 0x000000FF),
(AA & 0x0000FF00) >> 8,
(AA & 0x00FF0000) >> 16,
(AA & 0xFF000000) >> 24);

printf("%02X%02X%02X%02X",
(BB & 0x000000FF),
(BB & 0x0000FF00) >> 8,
(BB & 0x00FF0000) >> 16,
(BB & 0xFF000000) >> 24);

printf("%02X%02X%02X%02X",
(CC & 0x000000FF),
(CC & 0x0000FF00) >> 8,
(CC & 0x00FF0000) >> 16,
(CC & 0xFF000000) >> 24);

printf("%02X%02X%02X%02X",
(DD & 0x000000FF),
(DD & 0x0000FF00) >> 8,
(DD & 0x00FF0000) >> 16,
(DD & 0xFF000000) >> 24);

printf("\n");

return 0;
}

int main()
{
MD5("",0);
MD5("a",1);
MD5("abc",3);
MD5("message digest",14);
MD5("abcdefghijklmnopqrstuvwxyz",26);

return 0;
}

4. 如何在Linux下用C语言实现MD5/DES解密

相关库函数如下：
#include <openssl/md5.h>
unsigned char *MD5(const unsigned char *d, unsigned long n,unsigned char *md);
int MD5_Init(MD5_CTX *c);
int MD5_Update(MD5_CTX *c, const void *data,unsigned long len);
int MD5_Final(unsigned char *md, MD5_CTX *c);