c++实现MD5算法代码示例

发布时间:2013-9-24

本文导语: MD5算法是一种消息摘要算法(Message Digest Algorithm)，此算法以任意长度的信息(message)作为输入进行计算，产生一个128-bit(16-byte)的指纹或报文摘要(fingerprint or message digest)。两个不同的message产生相同message digest的几率相当小，从...

MD5 算法是一种高分求:LINUX下视频压缩编解码算法实现 iis7站长之家摘要算法(Message Digest Algorithm)，此算法以任意长度的信息(message)作为输入进行计算，产生一个128-bit(16-byte)的指纹或报文摘要(fingerprint or message digest)。两个不同的message产生相同message digest的几率相当小，从一个给定的message digest逆向产生原始message更是困难(不过据说我国的某个教授很善于从message digest构造message)，因此MD5算法适合用在数字签名应用中。MD5实现简单，在32位的机器上运行速度也相当快，当然实际应用也不仅仅局限于数字签名。

下面提供一份基于c++实现的md5算法供参考,md5算法源码包括md5.h和md5.cpp两个文件。

Md5.h文件源码:

#ifndef _MD5_H
#define _MD5_H
//#pragma warning(disable:4786)
#include <string>
using namespace std;
/*!
* Manage MD5.
* http://www. 收集整理
*/
class CMD5
{
private:
#define uint8 unsigned char
#define uint32 unsigned long int
struct md5_context
{
   uint32 total[2];
   uint32 state[4];
   uint8 buffer[64];
};
void md5_starts( struct md5_context *ctx );
void md5_process( struct md5_context *ctx, uint8 data[64] );
void md5_update( struct md5_context *ctx, uint8 *input, uint32 length );
void md5_finish( struct md5_context *ctx, uint8 digest[16] );
public:
//! construct a CMD5 from any buffer
void GenerateMD5(unsigned char* buffer,int bufferlen);
//! construct a CMD5
CMD5();
//! construct a md5src from char *
CMD5(const char * md5src);
//! construct a CMD5 from a 16 bytes md5
CMD5(unsigned long* md5src);
//! add a other md5
CMD5 operator +(CMD5 adder);
//! just if equal
bool operator ==(CMD5 cmper);
//! give the value from equer
// void operator =(CMD5 equer);
//! to a string
string ToString();
unsigned long m_data[4];
};
#endif /* md5.h */

Md5.cpp文件源代码如下:

/*
* RFC 1321 compliant MD5 implementation,
* by Christophe Devine <devine@cr0.net>;
* this program is licensed under the GPL.
*/
#include "Md5.h" 
#include <stdio.h> 
#include <stdlib.h> 
#include <string.h> 
#define GET_UINT32(n,b,i)                                        
{                                                                
    (n) = (uint32) ((uint8 *) b)[(i)]                            
      | (((uint32) ((uint8 *) b)[(i)+1]) << 8)                  
      | (((uint32) ((uint8 *) b)[(i)+2]) << 16)                  
      | (((uint32) ((uint8 *) b)[(i)+3]) << 24);                 
} 
#define PUT_UINT32(n,b,i)                                        
{                                                                
    (((uint8 *) b)[(i)] ) = (uint8) (((n)      ) & 0xFF);       
    (((uint8 *) b)[(i)+1]) = (uint8) (((n) >> 8) & 0xFF);       
    (((uint8 *) b)[(i)+2]) = (uint8) (((n) >> 16) & 0xFF);       
    (((uint8 *) b)[(i)+3]) = (uint8) (((n) >> 24) & 0xFF);       
} 
//extern pthread_mutex_t mutexMemory; 
void CMD5::md5_starts( struct md5_context *ctx ) 
{ 
    ctx->total[0] = 0; 
    ctx->total[1] = 0; 
    ctx->state[0] = 0x67452301; 
    ctx->state[1] = 0xEFCDAB89; 
    ctx->state[2] = 0x98BADCFE; 
    ctx->state[3] = 0x10325476; 
} 
void CMD5::md5_process( struct md5_context *ctx, uint8 data[64] ) 
{ 
    uint32 A, B, C, D, X[16]; 
    GET_UINT32( X[0], data, 0 ); 
    GET_UINT32( X[1], data, 4 ); 
    GET_UINT32( X[2], data, 8 ); 
    GET_UINT32( X[3], data, 12 ); 
    GET_UINT32( X[4], data, 16 ); 
    GET_UINT32( X[5], data, 20 ); 
    GET_UINT32( X[6], data, 24 ); 
    GET_UINT32( X[7], data, 28 ); 
    GET_UINT32( X[8], data, 32 ); 
    GET_UINT32( X[9], data, 36 ); 
    GET_UINT32( X[10], data, 40 ); 
    GET_UINT32( X[11], data, 44 ); 
    GET_UINT32( X[12], data, 48 ); 
    GET_UINT32( X[13], data, 52 ); 
    GET_UINT32( X[14], data, 56 ); 
    GET_UINT32( X[15], data, 60 ); 
#define S(x,n) ((x << n) | ((x & 0xFFFFFFFF) >> (32 - n))) 
#define P(a,b,c,d,k,s,t)                                 
{                                                        
    a += F(b,c,d) + X[k] + t; a = S(a,s) + b;            
} 
    A = ctx->state[0]; 
    B = ctx->state[1]; 
    C = ctx->state[2]; 
    D = ctx->state[3]; 
#define F(x,y,z) (z ^ (x & (y ^ z))) 
    P( A, B, C, D, 0, 7, 0xD76AA478 ); 
    P( D, A, B, C, 1, 12, 0xE8C7B756 ); 
    P( C, D, A, B, 2, 17, 0x242070DB ); 
    P( B, C, D, A, 3, 22, 0xC1BDCEEE ); 
    P( A, B, C, D, 4, 7, 0xF57C0FAF ); 
    P( D, A, B, C, 5, 12, 0x4787C62A ); 
    P( C, D, A, B, 6, 17, 0xA8304613 ); 
    P( B, C, D, A, 7, 22, 0xFD469501 ); 
    P( A, B, C, D, 8, 7, 0x698098D8 ); 
    P( D, A, B, C, 9, 12, 0x8B44F7AF ); 
    P( C, D, A, B, 10, 17, 0xFFFF5BB1 ); 
    P( B, C, D, A, 11, 22, 0x895CD7BE ); 
    P( A, B, C, D, 12, 7, 0x6B901122 ); 
    P( D, A, B, C, 13, 12, 0xFD987193 ); 
    P( C, D, A, B, 14, 17, 0xA679438E ); 
    P( B, C, D, A, 15, 22, 0x49B40821 ); 
#undef F 
#define F(x,y,z) (y ^ (z & (x ^ y))) 
    P( A, B, C, D, 1, 5, 0xF61E2562 ); 
    P( D, A, B, C, 6, 9, 0xC040B340 ); 
    P( C, D, A, B, 11, 14, 0x265E5A51 ); 
    P( B, C, D, A, 0, 20, 0xE9B6C7AA ); 
    P( A, B, C, D, 5, 5, 0xD62F105D ); 
    P( D, A, B, C, 10, 9, 0x02441453 ); 
    P( C, D, A, B, 15, 14, 0xD8A1E681 ); 
    P( B, C, D, A, 4, 20, 0xE7D3FBC8 ); 
    P( A, B, C, D, 9, 5, 0x21E1CDE6 ); 
    P( D, A, B, C, 14, 9, 0xC33707D6 ); 
    P( C, D, A, B, 3, 14, 0xF4D50D87 ); 
    P( B, C, D, A, 8, 20, 0x455A14ED ); 
    P( A, B, C, D, 13, 5, 0xA9E3E905 ); 
    P( D, A, B, C, 2, 9, 0xFCEFA3F8 ); 
    P( C, D, A, B, 7, 14, 0x676F02D9 ); 
    P( B, C, D, A, 12, 20, 0x8D2A4C8A ); 
#undef F 
#define F(x,y,z) (x ^ y ^ z) 
    P( A, B, C, D, 5, 4, 0xFFFA3942 ); 
    P( D, A, B, C, 8, 11, 0x8771F681 ); 
    P( C, D, A, B, 11, 16, 0x6D9D6122 ); 
    P( B, C, D, A, 14, 23, 0xFDE5380C ); 
    P( A, B, C, D, 1, 4, 0xA4BEEA44 ); 
    P( D, A, B, C, 4, 11, 0x4BDECFA9 ); 
    P( C, D, A, B, 7, 16, 0xF6BB4B60 ); 
    P( B, C, D, A, 10, 23, 0xBEBFBC70 ); 
    P( A, B, C, D, 13, 4, 0x289B7EC6 ); 
    P( D, A, B, C, 0, 11, 0xEAA127FA ); 
    P( C, D, A, B, 3, 16, 0xD4EF3085 ); 
    P( B, C, D, A, 6, 23, 0x04881D05 ); 
    P( A, B, C, D, 9, 4, 0xD9D4D039 ); 
    P( D, A, B, C, 12, 11, 0xE6DB99E5 ); 
    P( C, D, A, B, 15, 16, 0x1FA27CF8 ); 
    P( B, C, D, A, 2, 23, 0xC4AC5665 ); 
#undef F 
#define F(x,y,z) (y ^ (x | ~z)) 
    P( A, B, C, D, 0, 6, 0xF4292244 ); 
    P( D, A, B, C, 7, 10, 0x432AFF97 ); 
    P( C, D, A, B, 14, 15, 0xAB9423A7 ); 
    P( B, C, D, A, 5, 21, 0xFC93A039 ); 
    P( A, B, C, D, 12, 6, 0x655B59C3 ); 
    P( D, A, B, C, 3, 10, 0x8F0CCC92 ); 
    P( C, D, A, B, 10, 15, 0xFFEFF47D ); 
    P( B, C, D, A, 1, 21, 0x85845DD1 ); 
    P( A, B, C, D, 8, 6, 0x6FA87E4F ); 
    P( D, A, B, C, 15, 10, 0xFE2CE6E0 ); 
    P( C, D, A, B, 6, 15, 0xA3014314 ); 
    P( B, C, D, A, 13, 21, 0x4E0811A1 ); 
    P( A, B, C, D, 4, 6, 0xF7537E82 ); 
    P( D, A, B, C, 11, 10, 0xBD3AF235 ); 
    P( C, D, A, B, 2, 15, 0x2AD7D2BB ); 
    P( B, C, D, A, 9, 21, 0xEB86D391 ); 
#undef F 
    ctx->state[0] += A; 
    ctx->state[1] += B; 
    ctx->state[2] += C; 
    ctx->state[3] += D; 
} 
void CMD5::md5_update( struct md5_context *ctx, uint8 *input, uint32 length ) 
{ 
    uint32 left, fill; 
    if( ! length ) return; 
    left = ( ctx->total[0] >> 3 ) & 0x3F; 
    fill = 64 - left; 
    ctx->total[0] += length << 3; 
    ctx->total[1] += length >> 29; 
    ctx->total[0] &= 0xFFFFFFFF; 
    ctx->total[1] += ctx->total[0] < length << 3; 
    if( left && length >= fill ) 
    { 
        memcpy( (void *) (ctx->buffer + left), (void *) input, fill ); 
        md5_process( ctx, ctx->buffer ); 
        length -= fill; 
        input += fill; 
        left = 0; 
    } 
    while( length >= 64 ) 
    { 
        md5_process( ctx, input ); 
        length -= 64; 
        input += 64; 
    } 
    if( length ) 
    { 
        memcpy( (void *) (ctx->buffer + left), (void *) input, length ); 
    } 
} 
static uint8 md5_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 
}; 
void CMD5::md5_finish( struct md5_context *ctx, uint8 digest[16] ) 
{ 
    uint32 last, padn; 
    uint8 msglen[8]; 
    PUT_UINT32( ctx->total[0], msglen, 0 ); 
    PUT_UINT32( ctx->total[1], msglen, 4 ); 
    last = ( ctx->total[0] >> 3 ) & 0x3F; 
    padn = ( last < 56 ) ? ( 56 - last ) : ( 120 - last ); 
    md5_update( ctx, md5_padding, padn ); 
    md5_update( ctx, msglen, 8 ); 
    PUT_UINT32( ctx->state[0], digest, 0 ); 
    PUT_UINT32( ctx->state[1], digest, 4 ); 
    PUT_UINT32( ctx->state[2], digest, 8 ); 
    PUT_UINT32( ctx->state[3], digest, 12 ); 
} 
void CMD5::GenerateMD5(unsigned char* buffer,int bufferlen) 
{ 
    struct md5_context context; 
    md5_starts (&context); 
    md5_update (&context, buffer, bufferlen); 
    md5_finish (&context,(unsigned char*)m_data); 
} 
CMD5::CMD5() 
{ 
    for(int i=0;i<4;i++) 
        m_data[i]=0; 
} 
CMD5::CMD5(unsigned long* md5src) 
{ 
    memcpy(m_data,md5src,16); 
} 
int _httoi(const char *value) 
{ 
struct CHexMap 
{ 
    char chr; 
    int value; 
}; 
const int HexMapL = 16; 
CHexMap HexMap[HexMapL] = 
{ 
    {'0', 0}, {'1', 1}, 
    {'2', 2}, {'3', 3}, 
    {'4', 4}, {'5', 5}, 
    {'6', 6}, {'7', 7}, 
    {'8', 8}, {'9', 9}, 
    {'a', 10}, {'b', 11}, 
    {'c', 12}, {'d', 13}, 
    {'e', 14}, {'f', 15} 
}; 
//pthread_mutex_lock(&mutexMemory); 
char *mstr = strdup(value); 
//pthread_mutex_unlock(&mutexMemory); 
char *s = mstr; 
int result = 0; 
if (*s == '0' && *(s + 1) == 'X') s += 2; 
bool firsttime = true; 
while (*s != '') 
{ 
    bool found = false; 
    for (int i = 0; i < HexMapL; i++) 
    { 
      if (*s == HexMap[i].chr) 
      { 
        if (!firsttime) result <<= 4; 
        result |= HexMap[i].value; 
        found = true; 
        break; 
      } 
    } 
    if (!found) break; 
    s++; 
    firsttime = false; 
} 
//pthread_mutex_lock(&mutexMemory); 
free(mstr); 
//pthread_mutex_unlock(&mutexMemory); 
return result; 
} 
CMD5::CMD5(const char* md5src) 
{ 
    if (strcmp(md5src,"")==0) 
    { 
        for(int i=0;i<4;i++) 
            m_data[i]=0; 
        return; 
    } 
    for(int j = 0; j < 16; j++ ) 
    { 
        char buf[10]; 
        strncpy(buf,md5src,2); 
        md5src+=2; 
        ((unsigned char*)m_data)[j] = _httoi(buf); 
    } 
} 
CMD5 CMD5::operator +(CMD5 adder) 
{ 
    unsigned long m_newdata[4]; 
    for(int i=0;i<4;i++) 
        m_newdata[i]=m_data[i]^(adder.m_data[i]); 
    return CMD5(m_newdata); 
} 
bool CMD5::operator ==(CMD5 cmper) 
{ 
    return (memcmp(cmper.m_data ,m_data,16)==0); 
} 
//void CMD5::operator =(CMD5 equer) 
//{ 
// memcpy(m_data,equer.m_data ,16); 
//} 
string CMD5::ToString() 
{ 
    char output[33]; 
    for(int j = 0; j < 16; j++ ) 
    { 
        sprintf( output + j * 2, "%02x", ((unsigned char*)m_data)[j]); 
    } 
    return string(output); 
}

使用MD5示例代码:

#include "md5.h"
#include <string>
#include <iostream>
int main()
{
string c,key; 
cin >> c; 
if( c == "c" ) return(0); 
CMD5 iMD5; 
iMD5.GenerateMD5( (unsigned char*)c.c_str(), c.size() ); 
key = iMD5.ToString();
}

以上源代码搜集自互联网，仅供参考。

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