3 MD5算法
md5算法定義在RFC 1321中,由Ron Rivest(RSA公司)在1992年提出。然而很多學者已經找出了構造md5沖突的方法。這些人中包括中國山東大學的王教授和Hans Dobbertin。所以,單純使用md5的信息認證模式變得不可靠了。但並不是說md5不能夠使用。
md5算法的計算步驟:
md5參考代碼如下:
說明:
define.h的內容如下:
//define variable types
typedef unsigned char UI8;
typedef char I8;
typedef unsigned short UI16;
typedef short I16;
typedef unsigned int UI32;
typedef int I32;
typedef unsigned __int64 UI64;
typedef __int64 I64;
md5.h的內容如下:
#ifndef Goodzzp_MD5_05_10_13_16
#define Goodzzp_MD5_05_10_13_16
//md5 algorithm ,md5 class
//program by Goodzzp
//2005.10.13
#include "define.h"
//F, G, H and I are basic MD5 functions.
#define md5_F(x, y, z) (((x) & (y)) | ((~x) & (z)))
#define md5_G(x, y, z) (((x) & (z)) | ((y) & (~z)))
#define md5_H(x, y, z) ((x) ^ (y) ^ (z))
#define md5_I(x, y, z) ((y) ^ ((x) | (~z)))
// ROTATE_LEFT rotates x left n bits.
// x<<<=n;
#define md5_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 md5_FF(a, b, c, d, x, s, ac) { /
(a) += md5_F ((b), (c), (d)) + (x) + (ac); /
(a) = md5_ROTATE_LEFT ((a), (s)); /
(a) += (b); /
}
#define md5_GG(a, b, c, d, x, s, ac) { /
(a) += md5_G ((b), (c), (d)) + (x) + (ac); /
(a) = md5_ROTATE_LEFT ((a), (s)); /
(a) += (b); /
}
#define md5_HH(a, b, c, d, x, s, ac) { /
(a) += md5_H ((b), (c), (d)) + (x) + (ac); /
(a) = md5_ROTATE_LEFT ((a), (s)); /
(a) += (b); /
}
#define md5_II(a, b, c, d, x, s, ac) { /
(a) += md5_I ((b), (c), (d)) + (x) + (ac); /
(a) = md5_ROTATE_LEFT ((a), (s)); /
(a) += (b); /
}
// Constants for MD5Transform routine.
#define md5_S11 7
#define md5_S12 12
#define md5_S13 17
#define md5_S14 22
#define md5_S21 5
#define md5_S22 9
#define md5_S23 14
#define md5_S24 20
#define md5_S31 4
#define md5_S32 11
#define md5_S33 16
#define md5_S34 23
#define md5_S41 6
#define md5_S42 10
#define md5_S43 15
#define md5_S44 21
//md5散列類
class MD5
{
public:
//輸出結果的長度(字節)
static UI32 OutDataLength()
{
return 4*4;
}
//MD5變換函數
//out:輸出,長度為16,要求事先已經分配了內存
//in:輸入
//length:輸入值的長度
void Hash(UI8 *out,const UI8 *in,UI32 length)
{
UI32 i = length>>6,j=(length&0x3f),k;
//對數據64 64個字節的計算
for(k=0;k {
StepTransform((UI8 *)(in + k * 64),64,length);
}
//最后計算尾數
StepTransform((UI8 *)(in + 64 * i),j,length);
//拷貝輸出
memcpy(out,m_state,4*4);
//恢復m_state值
MD5();
}
//初始化
//這里就是4個剛開始的值
MD5()
{
m_state[0] = 0x67452301L;
m_state[1] = 0xefcdab89L;
m_state[2] = 0x98badcfeL;
m_state[3] = 0x10325476L;
}
private:
//每步的變換函數
//輸入:
// data: 要處理的數據塊(不大於64字節)
// dataBlockLen: 數據塊的長度
// dataTotalLen: 要處理的所有數據塊的總長度
//輸出結果保存在m_state里面
void StepTransform(UI8 *data,UI32 dataBlockLen, UI32 dataTotalLen)
{
UI8 buffer[64];
UI32 len=dataTotalLen*8;
memset(buffer,0,64);//清空數據為0
memcpy(buffer,data,dataBlockLen);//拷貝數據到緩沖
if(dataBlockLen <64) //需要增加數據
{
if(dataBlockLen<56)//當前數據是最后若干個,而且不需要增加一次變換
{
//添加1和0
buffer[dataBlockLen]=0x80;
//添加長度
buffer[56]=(UI8)(len&0xff);
len>>=8;
buffer[57]=(UI8)(len&0xff);
len>>=8;
buffer[58]=(UI8)(len&0xff);
len>>=8;
buffer[59]=(UI8)(len&0xff);
//變換
FirstTransform((UI32*)buffer);
CoreTransform();
}
else if(dataBlockLen>=56)
{
//添加1和0
buffer[dataBlockLen]=0x80;
//變換
FirstTransform((UI32*)buffer);
CoreTransform();
//添加長度
memset(buffer,0,64);
buffer[56]=(UI8)(len&0xff);
len>>=8;
buffer[57]=(UI8)(len&0xff);
len>>=8;
buffer[58]=(UI8)(len&0xff);
len>>=8;
buffer[59]=(UI8)(len&0xff);
//變換
FirstTransform((UI32*)buffer);
CoreTransform();
}
}
else if(dataBlockLen == 64)
{
//變換
FirstTransform((UI32*)buffer);
CoreTransform();
}
}
//把64字節的原始數據data進行初步轉化到m_data中去
void FirstTransform(UI32 *data)
{
memcpy(m_data,data,64);
}
//核心變換
void CoreTransform()
{
UI32 a = m_state[0];
UI32 b = m_state[1];
UI32 c = m_state[2];
UI32 d = m_state[3];
/* Round 1 */
md5_FF (a, b, c, d, m_data[ 0], md5_S11, 0xd76aa478); /* 1 */
md5_FF (d, a, b, c, m_data[ 1], md5_S12, 0xe8c7b756); /* 2 */
md5_FF (c, d, a, b, m_data[ 2], md5_S13, 0x242070db); /* 3 */
md5_FF (b, c, d, a, m_data[ 3], md5_S14, 0xc1bdceee); /* 4 */
md5_FF (a, b, c, d, m_data[ 4], md5_S11, 0xf57c0faf); /* 5 */
md5_FF (d, a, b, c, m_data[ 5], md5_S12, 0x4787c62a); /* 6 */
md5_FF (c, d, a, b, m_data[ 6], md5_S13, 0xa8304613); /* 7 */
md5_FF (b, c, d, a, m_data[ 7], md5_S14, 0xfd469501); /* 8 */
md5_FF (a, b, c, d, m_data[ 8], md5_S11, 0x698098d8); /* 9 */
md5_FF (d, a, b, c, m_data[ 9], md5_S12, 0x8b44f7af); /* 10 */
md5_FF (c, d, a, b, m_data[10], md5_S13, 0xffff5bb1); /* 11 */
md5_FF (b, c, d, a, m_data[11], md5_S14, 0x895cd7be); /* 12 */
md5_FF (a, b, c, d, m_data[12], md5_S11, 0x6b901122); /* 13 */
md5_FF (d, a, b, c, m_data[13], md5_S12, 0xfd987193); /* 14 */
md5_FF (c, d, a, b, m_data[14], md5_S13, 0xa679438e); /* 15 */
md5_FF (b, c, d, a, m_data[15], md5_S14, 0x49b40821); /* 16 */
/* Round 2 */
md5_GG (a, b, c, d, m_data[ 1], md5_S21, 0xf61e2562); /* 17 */
md5_GG (d, a, b, c, m_data[ 6], md5_S22, 0xc040b340); /* 18 */
md5_GG (c, d, a, b, m_data[11], md5_S23, 0x265e5a51); /* 19 */
md5_GG (b, c, d, a, m_data[ 0], md5_S24, 0xe9b6c7aa); /* 20 */
md5_GG (a, b, c, d, m_data[ 5], md5_S21, 0xd62f105d); /* 21 */
md5_GG (d, a, b, c, m_data[10], md5_S22, 0x2441453); /* 22 */
md5_GG (c, d, a, b, m_data[15], md5_S23, 0xd8a1e681); /* 23 */
md5_GG (b, c, d, a, m_data[ 4], md5_S24, 0xe7d3fbc8); /* 24 */
md5_GG (a, b, c, d, m_data[ 9], md5_S21, 0x21e1cde6); /* 25 */
md5_GG (d, a, b, c, m_data[14], md5_S22, 0xc33707d6); /* 26 */
md5_GG (c, d, a, b, m_data[ 3], md5_S23, 0xf4d50d87); /* 27 */
md5_GG (b, c, d, a, m_data[ 8], md5_S24, 0x455a14ed); /* 28 */
md5_GG (a, b, c, d, m_data[13], md5_S21, 0xa9e3e905); /* 29 */
md5_GG (d, a, b, c, m_data[ 2], md5_S22, 0xfcefa3f8); /* 30 */
md5_GG (c, d, a, b, m_data[ 7], md5_S23, 0x676f02d9); /* 31 */
md5_GG (b, c, d, a, m_data[12], md5_S24, 0x8d2a4c8a); /* 32 */
/* Round 3 */
md5_HH (a, b, c, d, m_data[ 5], md5_S31, 0xfffa3942); /* 33 */
md5_HH (d, a, b, c, m_data[ 8], md5_S32, 0x8771f681); /* 34 */
md5_HH (c, d, a, b, m_data[11], md5_S33, 0x6d9d6122); /* 35 */
md5_HH (b, c, d, a, m_data[14], md5_S34, 0xfde5380c); /* 36 */
md5_HH (a, b, c, d, m_data[ 1], md5_S31, 0xa4beea44); /* 37 */
md5_HH (d, a, b, c, m_data[ 4], md5_S32, 0x4bdecfa9); /* 38 */
md5_HH (c, d, a, b, m_data[ 7], md5_S33, 0xf6bb4b60); /* 39 */
md5_HH (b, c, d, a, m_data[10], md5_S34, 0xbebfbc70); /* 40 */
md5_HH (a, b, c, d, m_data[13], md5_S31, 0x289b7ec6); /* 41 */
md5_HH (d, a, b, c, m_data[ 0], md5_S32, 0xeaa127fa); /* 42 */
md5_HH (c, d, a, b, m_data[ 3], md5_S33, 0xd4ef3085); /* 43 */
md5_HH (b, c, d, a, m_data[ 6], md5_S34, 0x4881d05); /* 44 */
md5_HH (a, b, c, d, m_data[ 9], md5_S31, 0xd9d4d039); /* 45 */
md5_HH (d, a, b, c, m_data[12], md5_S32, 0xe6db99e5); /* 46 */
md5_HH (c, d, a, b, m_data[15], md5_S33, 0x1fa27cf8); /* 47 */
md5_HH (b, c, d, a, m_data[ 2], md5_S34, 0xc4ac5665); /* 48 */
/* Round 4 */
md5_II (a, b, c, d, m_data[ 0], md5_S41, 0xf4292244); /* 49 */
md5_II (d, a, b, c, m_data[ 7], md5_S42, 0x432aff97); /* 50 */
md5_II (c, d, a, b, m_data[14], md5_S43, 0xab9423a7); /* 51 */
md5_II (b, c, d, a, m_data[ 5], md5_S44, 0xfc93a039); /* 52 */
md5_II (a, b, c, d, m_data[12], md5_S41, 0x655b59c3); /* 53 */
md5_II (d, a, b, c, m_data[ 3], md5_S42, 0x8f0ccc92); /* 54 */
md5_II (c, d, a, b, m_data[10], md5_S43, 0xffeff47d); /* 55 */
md5_II (b, c, d, a, m_data[ 1], md5_S44, 0x85845dd1); /* 56 */
md5_II (a, b, c, d, m_data[ 8], md5_S41, 0x6fa87e4f); /* 57 */
md5_II (d, a, b, c, m_data[15], md5_S42, 0xfe2ce6e0); /* 58 */
md5_II (c, d, a, b, m_data[ 6], md5_S43, 0xa3014314); /* 59 */
md5_II (b, c, d, a, m_data[13], md5_S44, 0x4e0811a1); /* 60 */
md5_II (a, b, c, d, m_data[ 4], md5_S41, 0xf7537e82); /* 61 */
md5_II (d, a, b, c, m_data[11], md5_S42, 0xbd3af235); /* 62 */
md5_II (c, d, a, b, m_data[ 2], md5_S43, 0x2ad7d2bb); /* 63 */
md5_II (b, c, d, a, m_data[ 9], md5_S44, 0xeb86d391); /* 64 */
//拷貝回去
m_state[0] += a;
m_state[1] += b;
m_state[2] += c;
m_state[3] += d;
}
private:
UI32 m_state[4]; //保存有md5輸出值
UI32 m_data[16]; //保存有每步變換時對輸入的初始化轉化值
};
#endif
說明:這個函數只有一個類和一個輸出函數,直接使用以下方式就能進行計算:
MD5 md5;
UI8 dataOut[16];
char *s="abc";
md5.Hash(dataOut,(UI8*)s,strlen(s));
代碼經過測試。作者歡迎您提出自己的意見和建議,但作者不對本代碼的安全和正確性付任何責任。
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