Question

MD5 的用法

MD5 的加密和解密

Answer 1

具体的一个MD5实现
=============================头文件Security.h===============================================
/*
使用方法：
char Md5Buffer[33];
CSecurity Security;
Security.MD5("a string",Md5Buffer);
执行完成之后Md5Buffer中即存储了由"a string"计算得到的MD5值
*/
// 下列 ifdef 块是创建使从 DLL 导出更简单的
// 宏的标准方法。此 DLL 中的所有文件都是用命令行上定义的 SECURITY_EXPORTS
// 符号编译的。在使用此 DLL 的
// 任何其他项目上不应定义此符号。这样，源文件中包含此文件的任何其他项目都会将
// SECURITY_API 函数视为是从此 DLL 导入的，而此 DLL 则将用此宏定义的
// 符号视为是被导出的。
//在使用该类的地方包含本文件即可
#ifdef SECURITY_EXPORTS
#define SECURITY_API __declspec(dllexport)
#else
#define SECURITY_API __declspec(dllimport)
#endif
/* POINTER defines a generic pointer type */
typedef unsigned char *POINTER;
/* UINT2 defines a two byte word */
typedef unsigned short int UINT2;
/* UINT4 defines a four byte word */
typedef unsigned long int UINT4;
#define PROTO_LIST(list) list
/* MD5 context. */
typedef struct _MD5_CTX
{
UINT4 state[4]; /* state (ABCD) */
UINT4 count[2]; /* number of bits, modulo 2^64 (lsb first) */
unsigned char buffer[64]; /* input buffer */
} MD5_CTX;
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
};
/* Constants for MD5Transform routine.
*/
#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
/* F, G, H and I are basic MD5 functions.
*/
#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)))
/* ROTATE_LEFT rotates x left n bits.
*/
#define ROTATE_LEFT(x, n) (((x) << (n)) | ((x) >> (32-(n))))
/* FF, GG, HH, and II transformations for rounds 1, 2, 3, and 4.
Rotation is separate from addition to prevent recomputation.
*/
#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); }
#define TEST_BLOCK_LEN 1000
#define TEST_BLOCK_COUNT 1000
// 此类是从 Security.dll 导出的
class SECURITY_API CSecurity
{
public:
CSecurity(void);
void CSecurity::MD5( const char *string ,char *lpMD5StringBuffer ) ;
private:
void MD5Transform PROTO_LIST ((UINT4 [4], unsigned char [64]));
void MD5_memcpy PROTO_LIST ((POINTER, POINTER, size_t));
void MD5_memset PROTO_LIST ((POINTER, int, size_t));
void MD5Init PROTO_LIST ((MD5_CTX *));
void MD5Update PROTO_LIST ((MD5_CTX *, unsigned char *, size_t));
void MD5Final PROTO_LIST ((unsigned char [16], MD5_CTX *));
void MDTimeTrial PROTO_LIST ((void));
void StringAddOne PROTO_LIST ((char *));
void Encode PROTO_LIST ((unsigned char *, UINT4 *, size_t));
void Decode PROTO_LIST ((UINT4 *, unsigned char *, size_t));
};
===============================Security.cpp====================================================
// Security.cpp : 定义 DLL 应用程序的入口点。
//
#include "stdafx.h"
#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<math.h>
#include<ctype.h>
#include "Security.h"
BOOL APIENTRY DllMain( HANDLE hModule,
DWORD ul_reason_for_call,
LPVOID lpReserved
)
{
switch (ul_reason_for_call)
{
case DLL_PROCESS_ATTACH:
case DLL_THREAD_ATTACH:
case DLL_THREAD_DETACH:
case DLL_PROCESS_DETACH:
break;
}
return TRUE;
}
// 这是已导出类的构造函数。
// 有关类定义的信息，请参阅 Security.h
CSecurity::CSecurity()
{
return;
}
/*
MD5 initialization. Begins an MD5 operation, writing a new context.
*/
void CSecurity::MD5Init( MD5_CTX *context )
{
context->count[0] = context->count[1] = 0;
/*
Load magic initialization constants.
*/
context->state[0] = 0x67452301;
context->state[1] = 0xefcdab89;
context->state[2] = 0x98badcfe;
context->state[3] = 0x10325476;
}
/*
MD5 block update operation. Continues an MD5 message-digest
operation, processing another message block, and updating the
context.
*/
void CSecurity::MD5Update(
MD5_CTX *context, /* context */
unsigned char *input, /* input block */
size_t inputLen /* length of input block */
)
{
size_t i, index, partLen;
/* Compute number of bytes mod 64 */
index = (size_t)((context->count[0] >> 3) & 0x3F);
/* Update number of bits */
if ((context->count[0] += ((UINT4)inputLen << 3))
< ((UINT4)inputLen << 3))
context->count[1]++;
context->count[1] += ((UINT4)inputLen >> 29);
partLen = 64 - index;
/* Transform as many times as possible. */
if (inputLen >= partLen) {
MD5_memcpy
((POINTER)&context->buffer[index], (POINTER)input, partLen);
MD5Transform (context->state, context->buffer);
for (i = partLen; i + 63 < inputLen; i += 64)
MD5Transform (context->state, &input);
index = 0;
}
else
i = 0;
/* Buffer remaining input */
MD5_memcpy
((POINTER)&context->buffer[index], (POINTER)&input,
inputLen-i);
}
/*
MD5 finalization. Ends an MD5 message-digest operation, writing the
the message digest and zeroizing the context.
*/
void CSecurity::MD5Final(
unsigned char digest[16], /* message digest */
MD5_CTX *context /* context */
)
{
unsigned char bits[8];
size_t index, padLen;
/* Save number of bits */
Encode (bits, context->count, 8);
/* Pad out to 56 mod 64. */
index = (size_t)((context->count[0] >> 3) & 0x3f);
padLen = (index < 56) ? (56 - index) : (120 - index);
MD5Update (context, PADDING, padLen);
/* Append length (before padding) */
MD5Update (context, bits, 8);
/* Store state in digest */
Encode (digest, context->state, 16);
/* Zeroize sensitive information. */
MD5_memset ((POINTER)context, 0, sizeof (*context));
}
/*
MD5 basic transformation. Transforms state based on block.
*/
void CSecurity::MD5Transform(
UINT4 state[4],
unsigned char block[64]
)
{
UINT4 a = state[0], b = state[1], c = state[2], d = state[3], x[16];
Decode (x, block, 64);
/* Round 1 */
FF (a, b, c, d, x[ 0], S11, 0xd76aa478); /* 1 */
FF (d, a, b, c, x[ 1], S12, 0xe8c7b756); /* 2 */
FF (c, d, a, b, x[ 2], S13, 0x242070db); /* 3 */
FF (b, c, d, a, x[ 3], S14, 0xc1bdceee); /* 4 */
FF (a, b, c, d, x[ 4], S11, 0xf57c0faf); /* 5 */
FF (d, a, b, c, x[ 5], S12, 0x4787c62a); /* 6 */
FF (c, d, a, b, x[ 6], S13, 0xa8304613); /* 7 */
FF (b, c, d, a, x[ 7], S14, 0xfd469501); /* 8 */
FF (a, b, c, d, x[ 8], S11, 0x698098d8); /* 9 */
FF (d, a, b, c, x[ 9], S12, 0x8b44f7af); /* 10 */
FF (c, d, a, b, x[10], S13, 0xffff5bb1); /* 11 */
FF (b, c, d, a, x[11], S14, 0x895cd7be); /* 12 */
FF (a, b, c, d, x[12], S11, 0x6b901122); /* 13 */
FF (d, a, b, c, x[13], S12, 0xfd987193); /* 14 */
FF (c, d, a, b, x[14], S13, 0xa679438e); /* 15 */
FF (b, c, d, a, x[15], S14, 0x49b40821); /* 16 */
/* Round 2 */
GG (a, b, c, d, x[ 1], S21, 0xf61e2562); /* 17 */
GG (d, a, b, c, x[ 6], S22, 0xc040b340); /* 18 */
GG (c, d, a, b, x[11], S23, 0x265e5a51); /* 19 */
GG (b, c, d, a, x[ 0], S24, 0xe9b6c7aa); /* 20 */
GG (a, b, c, d, x[ 5], S21, 0xd62f105d); /* 21 */
GG (d, a, b, c, x[10], S22, 0x2441453); /* 22 */
GG (c, d, a, b, x[15], S23, 0xd8a1e681); /* 23 */
GG (b, c, d, a, x[ 4], S24, 0xe7d3fbc8); /* 24 */
GG (a, b, c, d, x[ 9], S21, 0x21e1cde6); /* 25 */
GG (d, a, b, c, x[14], S22, 0xc33707d6); /* 26 */
GG (c, d, a, b, x[ 3], S23, 0xf4d50d87); /* 27 */
GG (b, c, d, a, x[ 8], S24, 0x455a14ed); /* 28 */
GG (a, b, c, d, x[13], S21, 0xa9e3e905); /* 29 */
GG (d, a, b, c, x[ 2], S22, 0xfcefa3f8); /* 30 */
GG (c, d, a, b, x[ 7], S23, 0x676f02d9); /* 31 */
GG (b, c, d, a, x[12], S24, 0x8d2a4c8a); /* 32 */
/* Round 3 */
HH (a, b, c, d, x[ 5], S31, 0xfffa3942); /* 33 */
HH (d, a, b, c, x[ 8], S32, 0x8771f681); /* 34 */
HH (c, d, a, b, x[11], S33, 0x6d9d6122); /* 35 */
HH (b, c, d, a, x[14], S34, 0xfde5380c); /* 36 */
HH (a, b, c, d, x[ 1], S31, 0xa4beea44); /* 37 */
HH (d, a, b, c, x[ 4], S32, 0x4bdecfa9); /* 38 */
HH (c, d, a, b, x[ 7], S33, 0xf6bb4b60); /* 39 */
HH (b, c, d, a, x[10], S34, 0xbebfbc70); /* 40 */
HH (a, b, c, d, x[13], S31, 0x289b7ec6); /* 41 */
HH (d, a, b, c, x[ 0], S32, 0xeaa127fa); /* 42 */
HH (c, d, a, b, x[ 3], S33, 0xd4ef3085); /* 43 */
HH (b, c, d, a, x[ 6], S34, 0x4881d05); /* 44 */
HH (a, b, c, d, x[ 9], S31, 0xd9d4d039); /* 45 */
HH (d, a, b, c, x[12], S32, 0xe6db99e5); /* 46 */
HH (c, d, a, b, x[15], S33, 0x1fa27cf8); /* 47 */
HH (b, c, d, a, x[ 2], S34, 0xc4ac5665); /* 48 */
/* Round 4 */
II (a, b, c, d, x[ 0], S41, 0xf4292244); /* 49 */
II (d, a, b, c, x[ 7], S42, 0x432aff97); /* 50 */
II (c, d, a, b, x[14], S43, 0xab9423a7); /* 51 */
II (b, c, d, a, x[ 5], S44, 0xfc93a039); /* 52 */
II (a, b, c, d, x[12], S41, 0x655b59c3); /* 53 */
II (d, a, b, c, x[ 3], S42, 0x8f0ccc92); /* 54 */
II (c, d, a, b, x[10], S43, 0xffeff47d); /* 55 */
II (b, c, d, a, x[ 1], S44, 0x85845dd1); /* 56 */
II (a, b, c, d, x[ 8], S41, 0x6fa87e4f); /* 57 */
II (d, a, b, c, x[15], S42, 0xfe2ce6e0); /* 58 */
II (c, d, a, b, x[ 6], S43, 0xa3014314); /* 59 */
II (b, c, d, a, x[13], S44, 0x4e0811a1); /* 60 */
II (a, b, c, d, x[ 4], S41, 0xf7537e82); /* 61 */
II (d, a, b, c, x[11], S42, 0xbd3af235); /* 62 */
II (c, d, a, b, x[ 2], S43, 0x2ad7d2bb); /* 63 */
II (b, c, d, a, x[ 9], S44, 0xeb86d391); /* 64 */
state[0] += a;
state[1] += b;
state[2] += c;
state[3] += d;
/* Zeroize sensitive information. */
MD5_memset ((POINTER)x, 0, sizeof (x));
}
/*
Encodes input (UINT4) into output (unsigned char).
Assumes len is a multiple of 4.
*/
void CSecurity::Encode(
unsigned char *output,
UINT4 *input,
size_t len
)
{
size_t i, j;
for (i = 0, j = 0; j < len; i++, j += 4) {
output[j] = (unsigned char)(input & 0xff);
output[j+1] = (unsigned char)((input >> 8) & 0xff);
output[j+2] = (unsigned char)((input >> 16) & 0xff);
output[j+3] = (unsigned char)((input >> 24) & 0xff);
}
}
/*
Decodes input (unsigned char) into output (UINT4).
Assumes len is a multiple of 4.
*/
void CSecurity::Decode(
UINT4 *output,
unsigned char *input,
size_t len
)
{
size_t i, j;
for (i = 0, j = 0; j < len; i++, j += 4)
output = ((UINT4)input[j]) | (((UINT4)input[j+1]) << 8) |
(((UINT4)input[j+2]) << 16) | (((UINT4)input[j+3]) << 24);
}
/*
Note: Replace "for loop" with standard memcpy if possible.
*/
void CSecurity::MD5_memcpy(
POINTER output,
POINTER input,
size_t len
)
{
size_t i;
for (i = 0; i < len; i++)
output = input;
}
/*
Note: Replace "for loop" with standard memset if possible.
*/
void CSecurity::MD5_memset(
POINTER output,
int value,
size_t len
)
{
size_t i;
for (i = 0; i < len; i++)
((char *)output) = (char)value;
}
/*
Digests a string and prints the result.
*/
void CSecurity::MD5( const char *string ,char *lpMD5StringBuffer )
{
MD5_CTX context;
unsigned char digest[16];
/*char output1[33]; */
static char output[33]={""};
/*size_t*/size_t len = strlen (string);
int i;
MD5Init( &context);
MD5Update( &context, (unsigned char*)string, len );
MD5Final( digest, &context );
for (i = 0; i < 16; i++)
{
sprintf(&(lpMD5StringBuffer[2*i]),"%02x",(unsigned char)digest);
sprintf(&(lpMD5StringBuffer[2*i+1]),"%02x",(unsigned char)(digest<<4));
}
for(i=0;i<32;i++)
{
output=lpMD5StringBuffer;
}
}
/*
get the string add one.
*/
void CSecurity::StringAddOne( char * orstring )
{
size_t len;
size_t i,n;
len = strlen(orstring);
n = len - 1;
for(i = n; i >= 0; i--)
{
if(orstring=='9')
{
orstring = 'A';
break;
}
else if(orstring=='Z')
{
orstring='a';
break;
}
else if(orstring=='z')
{
orstring='0';
continue;
}
else
orstring += 1;
break;
}
}
=============================stdafx.h=====================================
// stdafx.h : 标准系统包含文件的包含文件，
// 或是常用但不常更改的项目特定的包含文件
//
#pragma once
//导出
#define SECURITY_EXPORTS
#define WIN32_LEAN_AND_MEAN // 从 Windows 头中排除极少使用的资料
// Windows 头文件:
#include <windows.h>
// TODO: 在此处引用程序要求的附加头文件
============================stdafx.cpp========================================
// stdafx.cpp : 只包括标准包含文件的源文件
// Security.pch 将成为预编译头
// stdafx.obj 将包含预编译类型信息
#include "stdafx.h"
// TODO: 在 STDAFX.H 中
//引用任何所需的附加头文件，而不是在此文件中引用
=====================================================================
以上程序使用命令：@cl /GD /LD Security.cpp stdafx.cpp 编译即可