md5c語言加密演算法

1. 如何對字元串進行MD5加密,用C語言實現,給出源代碼和加密函數

UINT4 state[4]; /*存儲原始信息的bits數長度,不包括填充的bits,最長為2^64 bits*/ UINT4 count[2]; /*存放輸入的信息的緩沖區,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);/*用於bits填充的緩沖區,當欲加密的信息的bits數被512除其餘數為448時,需要填充的bits的最大值為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};/*接下來的這幾個宏定義是md5演算法規定的,就是對信息進行md5加密都要做的運算*/

2. 浠涔堟槸md5鍔犲瘑

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3. 求生成MD5碼的c或c++代碼

自己用C語言寫的簡單的MD5演算法實現。

#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) 位元組補齊
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) 附加數據的比特長度
bit_len = len * 8;
// (64位二進制數表示的)比特長度的低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);
// 不考慮比特長度超出32位無符號數表示範圍,所以高32位總是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)); // 循環左移
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語言實現MD5/DES解密

相關庫函數如下：
#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);