在移动端需要安全算法时，直接使用开源库可能不合适(开源库都比较大，也可以自己抽取需要的代码)，本Demo是根据MD5的原理来实现算法。
#ifndef _20140317_MD5_H_
#define _20140317_MD5_H_#include <string>
#include <memory.h>
#include <ctype.h>
#include <sstream>
#include <iostream>
#include <stdio.h>namespace comm
{
namespace util
{typedef struct _tag_ctx_md5
{
unsigned int _state[4];
unsigned int _count[2];
unsigned char _inner_data[64];
} ctx_md5, *p_ctx_md5;class MD5
{
public:
MD5(){}
~MD5(){}
private:
void md5_initialize(ctx_md5* p_ctx);
void md5_update(ctx_md5* p_ctx, const unsigned char *pdata,
unsigned int count);
void md5_finish(ctx_md5* p_ctx, unsigned char cid[16]);
void md5_handle(unsigned int *state, const unsigned char block[64]);
void md5_encode(unsigned char *output, const unsigned int *input,
unsigned int len);
void md5_decode(unsigned int *output, const unsigned char *input,
unsigned int len);
public:
std::string md5(const std::string&input);
};
}
} //comm::util
#endif//_20140317_MD5_H_
#include "md5.h"
using namespace comm::util;
#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)#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)))
#define ROTATE_LEFT(x, n) (((x) << (n)) | ((x) >> (32-(n))))#define FF(a, b, c, d, x, s, ac) { \
(a) += F ((b), (c), (d)) + (x) + (unsigned int)(ac); \
(a) = ROTATE_LEFT ((a), (s)); \
(a) += (b); \
}#define GG(a, b, c, d, x, s, ac) { \
(a) += G ((b), (c), (d)) + (x) + (unsigned int)(ac); \
(a) = ROTATE_LEFT ((a), (s)); \
(a) += (b); \
}#define HH(a, b, c, d, x, s, ac) { \
(a) += H ((b), (c), (d)) + (x) + (unsigned int)(ac); \
(a) = ROTATE_LEFT ((a), (s)); \
(a) += (b); \
}#define II(a, b, c, d, x, s, ac) { \
(a) += I ((b), (c), (d)) + (x) + (unsigned int)(ac); \
(a) = ROTATE_LEFT ((a), (s)); \
(a) += (b); \
}void MD5::md5_update(ctx_md5* p_ctx, const unsigned char *pdata,
unsigned int len)
{
unsigned int i = 0;
unsigned int index = (unsigned int) ((p_ctx->_count[0] >> 3) & 0x3F);unsigned int size = 64 - index;
if ((p_ctx->_count[0] += (len << 3)) < (len << 3))
p_ctx->_count[1]++;p_ctx->_count[1] += (len >> 29);
if (len >= size)
{
memcpy(&p_ctx->_inner_data[index], pdata, size);
md5_handle(p_ctx->_state, p_ctx->_inner_data);
for (i = size; i + 63 < len; i += 64)
{
md5_handle(p_ctx->_state, &pdata[i]);
}
index = 0;
}
memcpy(&p_ctx->_inner_data[index], &pdata[i], len - i);
}void MD5::md5_finish(ctx_md5* p_ctx, unsigned char cid[16])
{
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
};unsigned char val[8];
unsigned int v, size;md5_encode(val, p_ctx->_count, 8);
v = (unsigned int) ((p_ctx->_count[0] >> 3) & 0x3f);
size = (v < 56) ? (56 - v) : (120 - v);
md5_update(p_ctx, PADDING, size);
md5_update(p_ctx, val, 8);
md5_encode(cid, p_ctx->_state, 16);
md5_initialize(p_ctx);
}void MD5::md5_initialize(ctx_md5* p_ctx)
{
p_ctx->_count[0] = 0;
p_ctx->_count[1] = 0;
p_ctx->_state[0] = 0x67452301;
p_ctx->_state[1] = 0xefcdab89;
p_ctx->_state[2] = 0x98badcfe;
p_ctx->_state[3] = 0x10325476;
memset(p_ctx->_inner_data, 0, sizeof(p_ctx->_inner_data));
}void MD5::md5_handle(unsigned int *state, const unsigned char block[64])
{
unsigned int a = state[0], b = state[1], c = state[2], d = state[3];
unsigned int x[16];
md5_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, 0x02441453); /* 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, 0x04881d05); /* 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;memset(x, 0, sizeof(x));
}void MD5::md5_encode(unsigned char *outdata, const unsigned int *indata,unsigned int len)
{
unsigned int i, j;
for (i = 0, j = 0; j < len; i++, j += 4)
{
outdata[j + 0] = (unsigned char) ((indata[i]) & 0xff);
outdata[j + 1] = (unsigned char) ((indata[i] >> 8) & 0xff);
outdata[j + 2] = (unsigned char) ((indata[i] >> 16) & 0xff);
outdata[j + 3] = (unsigned char) ((indata[i] >> 24) & 0xff);
}
}void MD5::md5_decode(unsigned int *outdata, const unsigned char *indata,unsigned int len)
{
unsigned int i, j;
for (i = 0, j = 0; j < len; i++, j += 4)
{
outdata[i] = ((unsigned int) indata[j + 0])
| (((unsigned int) indata[j + 1]) << 8) |
(((unsigned int) indata[j + 2]) << 16)
| (((unsigned int) indata[j + 3]) << 24);
}
}
//二进制协议数据直接用string，会存在截断的情况，二进制的可用下面的接口
std::string MD5::md5(const std::string& strInput)
{
unsigned char md5_result_data[16]={0};
ctx_md5 md5;
md5_initialize(&md5);
md5_update(&md5, (unsigned char*)strInput.c_str(),strInput.length());
md5_finish(&md5, md5_result_data);std::stringstream oss;
oss<<md5_result_data;return oss.str();
}
//适用二进制协议，iLength为输入数据长度，cOut参数带出结果。
int MD5::md5(const char* cInput,int iLength,char* cOut)
{
unsigned char md5_result_data[16] ={ 0 };
ctx_md5 md5;
md5_initialize(&md5);
md5_update(&md5, (unsigned char*)cInput,(unsigned int)iLength);
md5_finish(&md5, md5_result_data); memcpy(cOut,md5_result_data,16);
return 0;
}int main(int argv,char**argc)
{
comm::util::MD5 md5;
std::string strResult = md5.md5("123456789");for(int i=0;i<strResult.length();i++)
{
printf("%X",strResult[i]&255);
}printf("\n");
return 0;
}
