VC++下使用md5函数

使用windows的动态链接库advapi32.dll.

此动态链接库提供以下md5函数：

MD5Init(&ctx);
MD5Update(&ctx,buf,len);
MD5Final(&ctx);

具体使用如下

新建文件 common.h

#include <windows.h>
/* Data structure for MD5 (Message-Digest) computation */
typedef struct {
 ULONG i[2];                          /* number of _bits_ handled mod 2^64 */
 ULONG buf[4];                                           /* scratch buffer */
 unsigned char in[64];                                     /* input buffer */
 unsigned char digest[16];            /* actual digest after MD5Final call */
} MD5_CTX;


#define MD5DIGESTLEN 16

#define PROTO_LIST(list)    list


/*
* MTS: Each of these assumes MD5_CTX is locked against simultaneous use.
*/
typedef void (WINAPI* PMD5Init) PROTO_LIST ((MD5_CTX *));
typedef void (WINAPI* PMD5Update) PROTO_LIST ((MD5_CTX *,const unsigned char *,unsigned int));
typedef void (WINAPI* PMD5Final )PROTO_LIST ((MD5_CTX *));

//end globle define

 

 

class Ccommon 
{
public:
  Ccommon();
 virtual ~Ccommon();
 const char * md5(const char * str);
 const char * Hex2ASC(const BYTE *Hex,int Len);
 PMD5Init MD5Init;
 PMD5Update MD5Update;
 PMD5Final MD5Final;

};

新建文件 common.cpp

#include "stdafx.h"
#include "common.h"

//
// Construction/Destruction
//

Ccommon::Ccommon()
{

}

Ccommon::~Ccommon()
{

}

const char * Ccommon::Hex2ASC(const BYTE *Hex,int Len)
{
	static char  ASC[4096 * 2];
	int    i;

	for (i = 0; i < Len; i++)
	{
		ASC[i * 2] = "0123456789abcdef"[Hex[i] >> 4];
		ASC[i * 2 + 1] = "0123456789abcdef"[Hex[i] & 0x0F];
	}
	ASC[i * 2] = 0;
	return ASC;
}


const char * Ccommon::md5(const char * str)
{
	MD5_CTX ctx;
	const unsigned char * buf = reinterpret_cast<const unsigned char *>(str);
	int len = strlen(str);
	HINSTANCE hDLL;
	if ( (hDLL = LoadLibraryA("advapi32.dll")) > 0 )
	{

		MD5Init = (PMD5Init)GetProcAddress(hDLL,"MD5Init");
		MD5Update = (PMD5Update)GetProcAddress(hDLL,"MD5Update");
		MD5Final = (PMD5Final)GetProcAddress(hDLL,"MD5Final");

		MD5Init(&ctx);
		MD5Update(&ctx,len);
		MD5Final(&ctx);
	}
	return Hex2ASC(ctx.digest,16);
}

调用方法

//引入头文件 
#include "common.h"
//声明类
Ccommon md5Class;
name=md5Class.md5(name);

注意事项

MD5加密后的大小写是由 Hex2ASC函数里

ASC[i * 2] = "0123456789abcdef"[Hex[i] >> 4];
ASC[i * 2 + 1] = "0123456789abcdef"[Hex[i] & 0x0F];

这两句代码控制的 这里我改为了小写 默认应该是大写 看大家需求而定

如果需要大写改为：

ASC[i * 2] = "0123456789ABCDEF"[Hex[i] >> 4];
ASC[i * 2 + 1] = "0123456789ABCDEF"[Hex[i] & 0x0F];