MD5算法描述
作者：rufi 2004.06.22
当我要写一个MD5算法的程序时，发现中英文的语言描述都有一些不确切的地方，某些个细节
讲得不清楚，或者说很费解。最后不得不拿出C语言的源程序来调试，这对于理解算法是很不
利的。于是就总结了一下我摸索到的一些要点。
1.来历
MD5的全称是message-digest algorithm 5(信息-摘要算法，在90年代初由mit laboratory
for computer science和rsa data security inc的ronald l. rivest开发出来，
经md2、md3和md4发展而来。 http://www.ietf.org/rfc/rfc1321.txt ，是一份最权威的文档，
由ronald l. rivest在1992年8月向ieft提交。
2.用途
MD5的作用是对一段信息(message)生成信息摘要(message-digest)，该摘要对该信息具有
唯一性,可以作为数字签名。用于验证文件的有效性(是否有丢失或损坏的数据),对用户
密码的加密，在哈希函数中计算散列值。
3.特点
输入一个任意长度的字节串，生成一个128位的整数。由于算法的某些不可逆特征，在加密应用
上有较好的安全性。并且，MD5算法的使用不需要支付任何版权费用。
4.说明
唯一性和不可逆性都不是绝对的，从理论上分析是一种多对一的关系，但两个不同的信息产生
相同摘要的概率很小。不可逆是指从输出反推输入所需的运算量和计算时间太大，使用穷搜字
典的方法又需要太多的存储空间。
5.算法描述
算法输入是一个字节串，每个字节是8个bit.
算法的执行分为以下几个步骤：
第一步，补位：
MD5算法先对输入的数据进行补位，使得数据的长度(以byte为单位)对64求余的结果是56。
即数据扩展至LEN=K*64+56个字节，K为整数。
补位方法：补一个1，然后补0至满足上述要求。相当于补一个0x80的字节，再补值
为0的字节。这一步里总共补充的字节数为0～63个。
第二步，附加数据长度：
用一个64位的整数表示数据的原始长度(以bit为单位)，将这个数字的8个字节按低位的在前，
高位在后的顺序附加在补位后的数据后面。这时，数据被填补后的总长度为：
LEN = K*64+56+8=(K+1)*64 Bytes。
※注意那个64位整数是输入数据的原始长度而不是填充字节后的长度,我就在这里栽了跟头.
第三步，初始化MD5参数：
有四个32位整数变量 (A,B,C,D) 用来计算信息摘要，每一个变量被初始化成以下
以十六进制数表示的数值，低位的字节在前面。
word A: 01 23 45 67
word B: 89 ab cd ef
word C: fe dc ba 98
word D: 76 54 32 10
※注意低位的字节在前面指的是Little Endian平台上内存中字节的排列方式， word B: 89 ab cd ef
word C: fe dc ba 98
word D: 76 54 32 10
而在程序中书写时，要写成：
A=0x67452301
B=0xefcdab89
C=0x98badcfe
D=0x10325476
第四步，定义四个MD5基本的按位操作函数： B=0xefcdab89
C=0x98badcfe
D=0x10325476
X，Y，Z为32位整数。
F(X,Y,Z) = (X and Y) or (not(X) and Z)
G(X,Y,Z) = (X and Z) or (Y and not(Z))
H(X,Y,Z) = X xor Y xor Z
I(X,Y,Z) = Y xor (X or not(Z))
再定义四个分别用于四轮变换的函数。 G(X,Y,Z) = (X and Z) or (Y and not(Z))
H(X,Y,Z) = X xor Y xor Z
I(X,Y,Z) = Y xor (X or not(Z))
设Mj表示消息的第j个子分组（从0到15），<<
第五步，对输入数据作变换。
处理数据，N是总的字节数，以64个字节为一组，每组作一次循环，每次循环进行四轮操作。
要变换的64个字节用16个32位的整数数组M[0 ...15]表示。而数组T[1 ... 64]表示一组常数，
T[i]为4294967296*abs(sin(i))的32位整数部分，i的单位是弧度,i的取值从1到64。
具体过程如下：
/* 设置主循环变量 */
For i = 0 to N/16-1 do
/*每循环一次，把数据原文存放在16个元素的数组X中. */
For j = 0 to 15 do
Set X[j] to M[i*16+j].
end /结束对J的循环
Set X[j] to M[i*16+j].
end /结束对J的循环
/* Save A as AA, B as BB, C as CC, and D as DD.
*/
AA = A
BB = B
CC = C
DD = D
*/
AA = A
BB = B
CC = C
DD = D
/* 第1轮*/
/* 以 [abcd k s i]表示如下操作
a = b + ((a + F(b,c,d) + X[k] + T[i]) <<< s). */
/* Do the following 16 operations. */
[ABCD 0 7 1] [DABC 1 12 2] [CDAB 2 17 3] [BCDA 3 22 4]
[ABCD 4 7 5] [DABC 5 12 6] [CDAB 6 17 7] [BCDA 7 22 8]
[ABCD 8 7 9] [DABC 9 12 10] [CDAB 10 17 11] [BCDA 11 22 12]
[ABCD 12 7 13] [DABC 13 12 14] [CDAB 14 17 15] [BCDA 15 22 16]
/* 以 [abcd k s i]表示如下操作
a = b + ((a + F(b,c,d) + X[k] + T[i]) <<< s). */
/* Do the following 16 operations. */
[ABCD 0 7 1] [DABC 1 12 2] [CDAB 2 17 3] [BCDA 3 22 4]
[ABCD 4 7 5] [DABC 5 12 6] [CDAB 6 17 7] [BCDA 7 22 8]
[ABCD 8 7 9] [DABC 9 12 10] [CDAB 10 17 11] [BCDA 11 22 12]
[ABCD 12 7 13] [DABC 13 12 14] [CDAB 14 17 15] [BCDA 15 22 16]
/* 第2轮* */
/* 以 [abcd k s i]表示如下操作
a = b + ((a + G(b,c,d) + X[k] + T[i]) <<< s). */
/* Do the following 16 operations. */
[ABCD 1 5 17] [DABC 6 9 18] [CDAB 11 14 19] [BCDA 0 20 20]
[ABCD 5 5 21] [DABC 10 9 22] [CDAB 15 14 23] [BCDA 4 20 24]
[ABCD 9 5 25] [DABC 14 9 26] [CDAB 3 14 27] [BCDA 8 20 28]
[ABCD 13 5 29] [DABC 2 9 30] [CDAB 7 14 31] [BCDA 12 20 32]
/* 以 [abcd k s i]表示如下操作
a = b + ((a + G(b,c,d) + X[k] + T[i]) <<< s). */
/* Do the following 16 operations. */
[ABCD 1 5 17] [DABC 6 9 18] [CDAB 11 14 19] [BCDA 0 20 20]
[ABCD 5 5 21] [DABC 10 9 22] [CDAB 15 14 23] [BCDA 4 20 24]
[ABCD 9 5 25] [DABC 14 9 26] [CDAB 3 14 27] [BCDA 8 20 28]
[ABCD 13 5 29] [DABC 2 9 30] [CDAB 7 14 31] [BCDA 12 20 32]
/* 第3轮*/
/* 以 [abcd k s i]表示如下操作
a = b + ((a + H(b,c,d) + X[k] + T[i]) <<< s). */
/* Do the following 16 operations. */
[ABCD 5 4 33] [DABC 8 11 34] [CDAB 11 16 35] [BCDA 14 23 36]
[ABCD 1 4 37] [DABC 4 11 38] [CDAB 7 16 39] [BCDA 10 23 40]
[ABCD 13 4 41] [DABC 0 11 42] [CDAB 3 16 43] [BCDA 6 23 44]
[ABCD 9 4 45] [DABC 12 11 46] [CDAB 15 16 47] [BCDA 2 23 48]
/* 以 [abcd k s i]表示如下操作
a = b + ((a + H(b,c,d) + X[k] + T[i]) <<< s). */
/* Do the following 16 operations. */
[ABCD 5 4 33] [DABC 8 11 34] [CDAB 11 16 35] [BCDA 14 23 36]
[ABCD 1 4 37] [DABC 4 11 38] [CDAB 7 16 39] [BCDA 10 23 40]
[ABCD 13 4 41] [DABC 0 11 42] [CDAB 3 16 43] [BCDA 6 23 44]
[ABCD 9 4 45] [DABC 12 11 46] [CDAB 15 16 47] [BCDA 2 23 48]
/* 第4轮*/
/* 以 [abcd k s i]表示如下操作
a = b + ((a + I(b,c,d) + X[k] + T[i]) <<< s). */
/* Do the following 16 operations. */
[ABCD 0 6 49] [DABC 7 10 50] [CDAB 14 15 51] [BCDA 5 21 52]
[ABCD 12 6 53] [DABC 3 10 54] [CDAB 10 15 55] [BCDA 1 21 56]
[ABCD 8 6 57] [DABC 15 10 58] [CDAB 6 15 59] [BCDA 13 21 60]
[ABCD 4 6 61] [DABC 11 10 62] [CDAB 2 15 63] [BCDA 9 21 64]
/* 以 [abcd k s i]表示如下操作
a = b + ((a + I(b,c,d) + X[k] + T[i]) <<< s). */
/* Do the following 16 operations. */
[ABCD 0 6 49] [DABC 7 10 50] [CDAB 14 15 51] [BCDA 5 21 52]
[ABCD 12 6 53] [DABC 3 10 54] [CDAB 10 15 55] [BCDA 1 21 56]
[ABCD 8 6 57] [DABC 15 10 58] [CDAB 6 15 59] [BCDA 13 21 60]
[ABCD 4 6 61] [DABC 11 10 62] [CDAB 2 15 63] [BCDA 9 21 64]
/* 然后进行如下操作 */
A = A + AA
B = B + BB
C = C + CC
D = D + DD
Next i /* 结束对I的循环*/ A = A + AA
B = B + BB
C = C + CC
D = D + DD
第六步，输出结果。
A，B，C，D连续存放，共16个字节，128位。按十六进制依次输出这个16个字节。
最后，用程序语言实现算法后，可以输入以下几个信息对程序作一个简单的测试，
看看程序有没有错误。
MD5 ("") = d41d8cd98f00b204e9800998ecf8427e
MD5 ("a") = 0cc175b9c0f1b6a831c399e269772661
MD5 ("abc") = 900150983cd24fb0d6963f7d28e17f72
MD5 ("message digest") = f96b697d7cb7938d525a2f31aaf161d0
MD5 ("abcdefghijklmnopqrstuvwxyz") = c3fcd3d76192e4007dfb496cca67e13b
MD5 ("ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789") =
d174ab98d277d9f5a5611c2c9f419d9f
MD5 ("123456789012345678901234567890123456789012345678901234567890123456789
01234567890") = 57edf4a22be3c955ac49da2e2107b67a
MD5算法之C#程序 MD5 ("a") = 0cc175b9c0f1b6a831c399e269772661
MD5 ("abc") = 900150983cd24fb0d6963f7d28e17f72
MD5 ("message digest") = f96b697d7cb7938d525a2f31aaf161d0
MD5 ("abcdefghijklmnopqrstuvwxyz") = c3fcd3d76192e4007dfb496cca67e13b
MD5 ("ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789") =
d174ab98d277d9f5a5611c2c9f419d9f
MD5 ("123456789012345678901234567890123456789012345678901234567890123456789
01234567890") = 57edf4a22be3c955ac49da2e2107b67a
MD5算法比较特别，最适合用汇编语言来写，好多高级语言对之无能无力或效率极低。
比如我最开始尝试用Python和Euphoria编写，发现不太容易。相比而言，C#作为C家簇
中新兴的一门.net语言，功能比较全面。花了一晚上的工夫终于用C#最先实现了MD5。
主要是由于对算法的一些细节不太注意，结果输出总是不对，调试了好长时间。
//源文件：md5.cs
// MD5 Alogrithm
// by rufi 2004.6.20 http://rufi.yculblog.com/
using System;
using System.Collections;
using System.IO;
public class MD5 {
//static state variables
private static UInt32 A;
private static UInt32 B;
private static UInt32 C;
private static UInt32 D;
//number of bits to rotate in tranforming
private const int S11 = 7;
private const int S12 = 12;
private const int S13 = 17;
private const int S14 = 22;
private const int S21 = 5;
private const int S22 = 9;
private const int S23 = 14;
private const int S24 = 20;
private const int S31 = 4;
private const int S32 = 11;
private const int S33 = 16;
private const int S34 = 23;
private const int S41 = 6;
private const int S42 = 10;
private const int S43 = 15;
private const int S44 = 21;
/* F, G, H and I are basic MD5 functions.
* 四个非线性函数:
*
* F(X,Y,Z) =(X&Y)|((~X)&Z)
* G(X,Y,Z) =(X&Z)|(Y&(~Z))
* H(X,Y,Z) =X^Y^Z
* I(X,Y,Z)=Y^(X|(~Z))
*
* （&与，|或，~非，^异或）
*/
private static UInt32 F(UInt32 x,UInt32 y,UInt32 z){
return (x&y)|((~x)&z);
}
private static UInt32 G(UInt32 x,UInt32 y,UInt32 z){
return (x&z)|(y&(~z));
}
private static UInt32 H(UInt32 x,UInt32 y,UInt32 z){
return x^y^z;
}
private static UInt32 I(UInt32 x,UInt32 y,UInt32 z){
return y^(x|(~z));
}
/* FF, GG, HH, and II transformations for rounds 1, 2, 3, and 4.
* Rotation is separate from addition to prevent recomputation.
*/
private static void FF(ref UInt32 a,UInt32 b,UInt32 c,UInt32 d,UInt32 mj,int s,UInt32 ti){
a = a + F(b,c,d) + mj + ti;
a = a << s | a >>(32-s);
a += b;
}
private static void GG(ref UInt32 a,UInt32 b,UInt32 c,UInt32 d,UInt32 mj,int s,UInt32 ti){
a = a + G(b,c,d) + mj + ti;
a = a << s | a >>(32-s);
a += b;
}
private static void HH(ref UInt32 a,UInt32 b,UInt32 c,UInt32 d,UInt32 mj,int s,UInt32 ti){
a = a + H(b,c,d) + mj + ti;
a = a << s | a >>(32-s);
a += b;
}
private static void II(ref UInt32 a,UInt32 b,UInt32 c,UInt32 d,UInt32 mj,int s,UInt32 ti){
a = a + I(b,c,d) + mj + ti;
a = a << s | a >>(32-s);
a += b;
}
private static void MD5_Init(){
A=0x67452301; //in memory, this is 0x01234567
B=0xefcdab89; //in memory, this is 0x89abcdef
C=0x98badcfe; //in memory, this is 0xfedcba98
D=0x10325476; //in memory, this is 0x76543210
}
private static UInt32[] MD5_Append(byte[] input){
int zeros=0;
int ones =1;
int size=0;
int n = input.Length;
int m = n%64;
if( m < 56 ){
zeros = 55-m;
size=n-m+64;
}
else if (m==56){
zeros = 0;
ones = 0;
size=n+8;
}
else{
zeros = 63-m+56;
size=n+64-m+64;
}
ArrayList bs = new ArrayList(input);
if(ones==1){
bs.Add( (byte)0x80 ); // 0x80 = $10000000
}
for(int i=0;ibs.Add( (byte)0 );
}
UInt64 N = (UInt64) n * 8;
byte h1=(byte)(N&0xFF);
byte h2=(byte)((N>>8)&0xFF);
byte h3=(byte)((N>>16)&0xFF);
byte h4=(byte)((N>>24)&0xFF);
byte h5=(byte)((N>>32)&0xFF);
byte h6=(byte)((N>>40)&0xFF);
byte h7=(byte)((N>>48)&0xFF);
byte h8=(byte)(N>>56);
bs.Add(h1);
bs.Add(h2);
bs.Add(h3);
bs.Add(h4);
bs.Add(h5);
bs.Add(h6);
bs.Add(h7);
bs.Add(h8);
byte[] ts=(byte[])bs.ToArray(typeof(byte));
/* Decodes input (byte[]) into output (UInt32[]). Assumes len is
* a multiple of 4.
*/
UInt32[] output = new UInt32[size/4];
for(Int64 i=0,j=0;ioutput[j]=(UInt32)(ts[i] | ts[i+1]<<8 | ts[i+2]<<16 | ts[i+3]<<24);
}
return output;
}
private static UInt32[] MD5_Trasform(UInt32[] x){
UInt32 a,b,c,d;
for(int k=0;ka=A;
b=B;
c=C;
d=D;
/* Round 1 */
FF (ref a, b, c, d, x[k+ 0], S11, 0xd76aa478); /* 1 */
FF (ref d, a, b, c, x[k+ 1], S12, 0xe8c7b756); /* 2 */
FF (ref c, d, a, b, x[k+ 2], S13, 0x242070db); /* 3 */
FF (ref b, c, d, a, x[k+ 3], S14, 0xc1bdceee); /* 4 */
FF (ref a, b, c, d, x[k+ 4], S11, 0xf57c0faf); /* 5 */
FF (ref d, a, b, c, x[k+ 5], S12, 0x4787c62a); /* 6 */
FF (ref c, d, a, b, x[k+ 6], S13, 0xa8304613); /* 7 */
FF (ref b, c, d, a, x[k+ 7], S14, 0xfd469501); /* 8 */
FF (ref a, b, c, d, x[k+ 8], S11, 0x698098d8); /* 9 */
FF (ref d, a, b, c, x[k+ 9], S12, 0x8b44f7af); /* 10 */
FF (ref c, d, a, b, x[k+10], S13, 0xffff5bb1); /* 11 */
FF (ref b, c, d, a, x[k+11], S14, 0x895cd7be); /* 12 */
FF (ref a, b, c, d, x[k+12], S11, 0x6b901122); /* 13 */
FF (ref d, a, b, c, x[k+13], S12, 0xfd987193); /* 14 */
FF (ref c, d, a, b, x[k+14], S13, 0xa679438e); /* 15 */
FF (ref b, c, d, a, x[k+15], S14, 0x49b40821); /* 16 */
/* Round 2 */
GG (ref a, b, c, d, x[k+ 1], S21, 0xf61e2562); /* 17 */
GG (ref d, a, b, c, x[k+ 6], S22, 0xc040b340); /* 18 */
GG (ref c, d, a, b, x[k+11], S23, 0x265e5a51); /* 19 */
GG (ref b, c, d, a, x[k+ 0], S24, 0xe9b6c7aa); /* 20 */
GG (ref a, b, c, d, x[k+ 5], S21, 0xd62f105d); /* 21 */
GG (ref d, a, b, c, x[k+10], S22, 0x2441453); /* 22 */
GG (ref c, d, a, b, x[k+15], S23, 0xd8a1e681); /* 23 */
GG (ref b, c, d, a, x[k+ 4], S24, 0xe7d3fbc8); /* 24 */
GG (ref a, b, c, d, x[k+ 9], S21, 0x21e1cde6); /* 25 */
GG (ref d, a, b, c, x[k+14], S22, 0xc33707d6); /* 26 */
GG (ref c, d, a, b, x[k+ 3], S23, 0xf4d50d87); /* 27 */
GG (ref b, c, d, a, x[k+ 8], S24, 0x455a14ed); /* 28 */
GG (ref a, b, c, d, x[k+13], S21, 0xa9e3e905); /* 29 */
GG (ref d, a, b, c, x[k+ 2], S22, 0xfcefa3f8); /* 30 */
GG (ref c, d, a, b, x[k+ 7], S23, 0x676f02d9); /* 31 */
GG (ref b, c, d, a, x[k+12], S24, 0x8d2a4c8a); /* 32 */
/* Round 3 */
HH (ref a, b, c, d, x[k+ 5], S31, 0xfffa3942); /* 33 */
HH (ref d, a, b, c, x[k+ 8], S32, 0x8771f681); /* 34 */
HH (ref c, d, a, b, x[k+11], S33, 0x6d9d6122); /* 35 */
HH (ref b, c, d, a, x[k+14], S34, 0xfde5380c); /* 36 */
HH (ref a, b, c, d, x[k+ 1], S31, 0xa4beea44); /* 37 */
HH (ref d, a, b, c, x[k+ 4], S32, 0x4bdecfa9); /* 38 */
HH (ref c, d, a, b, x[k+ 7], S33, 0xf6bb4b60); /* 39 */
HH (ref b, c, d, a, x[k+10], S34, 0xbebfbc70); /* 40 */
HH (ref a, b, c, d, x[k+13], S31, 0x289b7ec6); /* 41 */
HH (ref d, a, b, c, x[k+ 0], S32, 0xeaa127fa); /* 42 */
HH (ref c, d, a, b, x[k+ 3], S33, 0xd4ef3085); /* 43 */
HH (ref b, c, d, a, x[k+ 6], S34, 0x4881d05); /* 44 */
HH (ref a, b, c, d, x[k+ 9], S31, 0xd9d4d039); /* 45 */
HH (ref d, a, b, c, x[k+12], S32, 0xe6db99e5); /* 46 */
HH (ref c, d, a, b, x[k+15], S33, 0x1fa27cf8); /* 47 */
HH (ref b, c, d, a, x[k+ 2], S34, 0xc4ac5665); /* 48 */
/* Round 4 */
II (ref a, b, c, d, x[k+ 0], S41, 0xf4292244); /* 49 */
II (ref d, a, b, c, x[k+ 7], S42, 0x432aff97); /* 50 */
II (ref c, d, a, b, x[k+14], S43, 0xab9423a7); /* 51 */
II (ref b, c, d, a, x[k+ 5], S44, 0xfc93a039); /* 52 */
II (ref a, b, c, d, x[k+12], S41, 0x655b59c3); /* 53 */
II (ref d, a, b, c, x[k+ 3], S42, 0x8f0ccc92); /* 54 */
II (ref c, d, a, b, x[k+10], S43, 0xffeff47d); /* 55 */
II (ref b, c, d, a, x[k+ 1], S44, 0x85845dd1); /* 56 */
II (ref a, b, c, d, x[k+ 8], S41, 0x6fa87e4f); /* 57 */
II (ref d, a, b, c, x[k+15], S42, 0xfe2ce6e0); /* 58 */
II (ref c, d, a, b, x[k+ 6], S43, 0xa3014314); /* 59 */
II (ref b, c, d, a, x[k+13], S44, 0x4e0811a1); /* 60 */
II (ref a, b, c, d, x[k+ 4], S41, 0xf7537e82); /* 61 */
II (ref d, a, b, c, x[k+11], S42, 0xbd3af235); /* 62 */
II (ref c, d, a, b, x[k+ 2], S43, 0x2ad7d2bb); /* 63 */
II (ref b, c, d, a, x[k+ 9], S44, 0xeb86d391); /* 64 */
A+=a;
B+=b;
C+=c;
D+=d;
}
return new UInt32[]{A,B,C,D};
}
public static byte[] MD5Array(byte[] input){
MD5_Init();
UInt32[] block = MD5_Append(input);
UInt32[] bits = MD5_Trasform(block);
/* Encodes bits (UInt32[]) into output (byte[]). Assumes len is
* a multiple of 4.
*/
byte[] output=new byte[bits.Length*4];
for(int i=0,j=0;ioutput[j] = (byte)(bits[i] & 0xff);
output[j+1] = (byte)((bits[i] >>8) & 0xff);
output[j+2] = (byte)((bits[i] >>16) & 0xff);
output[j+3] = (byte)((bits[i] >>24) & 0xff);
}
return output;
}
public static string ArrayToHexString(byte[] array,bool uppercase){
string hexString="";
string format="x2";
if(uppercase){
format="X2";
}
foreach(byte b in array){
hexString += b.ToString(format);
}
return hexString;
}
public static string MDString(string message){
char[] c = message.ToCharArray();
byte[] b = new byte[c.Length];
for(int i=0;ib[i]=(byte)c[i];
}
byte[] digest = MD5Array(b);
return ArrayToHexString(digest,false);
}
public static string MDFile(string fileName){
FileStream fs=File.Open(fileName,FileMode.Open,FileAccess.Read);
byte[] array=new byte[fs.Length];
fs.Read(array,0,(int)fs.Length);
byte[] digest = MD5Array(array);
fs.Close();
return ArrayToHexString(digest,false);
}
public static string Test(string message){
return "rnMD5 (""+message+"") = " + MD5.MDString(message);
}
public static string TestSuite(){
string s = "";
s+=Test("");
s+=Test("a");
s+=Test("abc");
s+=Test("message digest");
s+=Test("abcdefghijklmnopqrstuvwxyz");
s+=Test("ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789");
s+=Test("12345678901234567890123456789012345678901234567890123456789012345678901234567890");
return s;
}
}
原文链接:http://www.itgoogle.com/web/show_1260.html
// MD5 Alogrithm
// by rufi 2004.6.20 http://rufi.yculblog.com/
using System;
using System.Collections;
using System.IO;
public class MD5 {
//static state variables
private static UInt32 A;
private static UInt32 B;
private static UInt32 C;
private static UInt32 D;
//number of bits to rotate in tranforming
private const int S11 = 7;
private const int S12 = 12;
private const int S13 = 17;
private const int S14 = 22;
private const int S21 = 5;
private const int S22 = 9;
private const int S23 = 14;
private const int S24 = 20;
private const int S31 = 4;
private const int S32 = 11;
private const int S33 = 16;
private const int S34 = 23;
private const int S41 = 6;
private const int S42 = 10;
private const int S43 = 15;
private const int S44 = 21;
/* F, G, H and I are basic MD5 functions.
* 四个非线性函数:
*
* F(X,Y,Z) =(X&Y)|((~X)&Z)
* G(X,Y,Z) =(X&Z)|(Y&(~Z))
* H(X,Y,Z) =X^Y^Z
* I(X,Y,Z)=Y^(X|(~Z))
*
* （&与，|或，~非，^异或）
*/
private static UInt32 F(UInt32 x,UInt32 y,UInt32 z){
return (x&y)|((~x)&z);
}
private static UInt32 G(UInt32 x,UInt32 y,UInt32 z){
return (x&z)|(y&(~z));
}
private static UInt32 H(UInt32 x,UInt32 y,UInt32 z){
return x^y^z;
}
private static UInt32 I(UInt32 x,UInt32 y,UInt32 z){
return y^(x|(~z));
}
/* FF, GG, HH, and II transformations for rounds 1, 2, 3, and 4.
* Rotation is separate from addition to prevent recomputation.
*/
private static void FF(ref UInt32 a,UInt32 b,UInt32 c,UInt32 d,UInt32 mj,int s,UInt32 ti){
a = a + F(b,c,d) + mj + ti;
a = a << s | a >>(32-s);
a += b;
}
private static void GG(ref UInt32 a,UInt32 b,UInt32 c,UInt32 d,UInt32 mj,int s,UInt32 ti){
a = a + G(b,c,d) + mj + ti;
a = a << s | a >>(32-s);
a += b;
}
private static void HH(ref UInt32 a,UInt32 b,UInt32 c,UInt32 d,UInt32 mj,int s,UInt32 ti){
a = a + H(b,c,d) + mj + ti;
a = a << s | a >>(32-s);
a += b;
}
private static void II(ref UInt32 a,UInt32 b,UInt32 c,UInt32 d,UInt32 mj,int s,UInt32 ti){
a = a + I(b,c,d) + mj + ti;
a = a << s | a >>(32-s);
a += b;
}
private static void MD5_Init(){
A=0x67452301; //in memory, this is 0x01234567
B=0xefcdab89; //in memory, this is 0x89abcdef
C=0x98badcfe; //in memory, this is 0xfedcba98
D=0x10325476; //in memory, this is 0x76543210
}
private static UInt32[] MD5_Append(byte[] input){
int zeros=0;
int ones =1;
int size=0;
int n = input.Length;
int m = n%64;
if( m < 56 ){
zeros = 55-m;
size=n-m+64;
}
else if (m==56){
zeros = 0;
ones = 0;
size=n+8;
}
else{
zeros = 63-m+56;
size=n+64-m+64;
}
ArrayList bs = new ArrayList(input);
if(ones==1){
bs.Add( (byte)0x80 ); // 0x80 = $10000000
}
for(int i=0;i
}
UInt64 N = (UInt64) n * 8;
byte h1=(byte)(N&0xFF);
byte h2=(byte)((N>>8)&0xFF);
byte h3=(byte)((N>>16)&0xFF);
byte h4=(byte)((N>>24)&0xFF);
byte h5=(byte)((N>>32)&0xFF);
byte h6=(byte)((N>>40)&0xFF);
byte h7=(byte)((N>>48)&0xFF);
byte h8=(byte)(N>>56);
bs.Add(h1);
bs.Add(h2);
bs.Add(h3);
bs.Add(h4);
bs.Add(h5);
bs.Add(h6);
bs.Add(h7);
bs.Add(h8);
byte[] ts=(byte[])bs.ToArray(typeof(byte));
/* Decodes input (byte[]) into output (UInt32[]). Assumes len is
* a multiple of 4.
*/
UInt32[] output = new UInt32[size/4];
for(Int64 i=0,j=0;i
}
return output;
}
private static UInt32[] MD5_Trasform(UInt32[] x){
UInt32 a,b,c,d;
for(int k=0;k
b=B;
c=C;
d=D;
/* Round 1 */
FF (ref a, b, c, d, x[k+ 0], S11, 0xd76aa478); /* 1 */
FF (ref d, a, b, c, x[k+ 1], S12, 0xe8c7b756); /* 2 */
FF (ref c, d, a, b, x[k+ 2], S13, 0x242070db); /* 3 */
FF (ref b, c, d, a, x[k+ 3], S14, 0xc1bdceee); /* 4 */
FF (ref a, b, c, d, x[k+ 4], S11, 0xf57c0faf); /* 5 */
FF (ref d, a, b, c, x[k+ 5], S12, 0x4787c62a); /* 6 */
FF (ref c, d, a, b, x[k+ 6], S13, 0xa8304613); /* 7 */
FF (ref b, c, d, a, x[k+ 7], S14, 0xfd469501); /* 8 */
FF (ref a, b, c, d, x[k+ 8], S11, 0x698098d8); /* 9 */
FF (ref d, a, b, c, x[k+ 9], S12, 0x8b44f7af); /* 10 */
FF (ref c, d, a, b, x[k+10], S13, 0xffff5bb1); /* 11 */
FF (ref b, c, d, a, x[k+11], S14, 0x895cd7be); /* 12 */
FF (ref a, b, c, d, x[k+12], S11, 0x6b901122); /* 13 */
FF (ref d, a, b, c, x[k+13], S12, 0xfd987193); /* 14 */
FF (ref c, d, a, b, x[k+14], S13, 0xa679438e); /* 15 */
FF (ref b, c, d, a, x[k+15], S14, 0x49b40821); /* 16 */
/* Round 2 */
GG (ref a, b, c, d, x[k+ 1], S21, 0xf61e2562); /* 17 */
GG (ref d, a, b, c, x[k+ 6], S22, 0xc040b340); /* 18 */
GG (ref c, d, a, b, x[k+11], S23, 0x265e5a51); /* 19 */
GG (ref b, c, d, a, x[k+ 0], S24, 0xe9b6c7aa); /* 20 */
GG (ref a, b, c, d, x[k+ 5], S21, 0xd62f105d); /* 21 */
GG (ref d, a, b, c, x[k+10], S22, 0x2441453); /* 22 */
GG (ref c, d, a, b, x[k+15], S23, 0xd8a1e681); /* 23 */
GG (ref b, c, d, a, x[k+ 4], S24, 0xe7d3fbc8); /* 24 */
GG (ref a, b, c, d, x[k+ 9], S21, 0x21e1cde6); /* 25 */
GG (ref d, a, b, c, x[k+14], S22, 0xc33707d6); /* 26 */
GG (ref c, d, a, b, x[k+ 3], S23, 0xf4d50d87); /* 27 */
GG (ref b, c, d, a, x[k+ 8], S24, 0x455a14ed); /* 28 */
GG (ref a, b, c, d, x[k+13], S21, 0xa9e3e905); /* 29 */
GG (ref d, a, b, c, x[k+ 2], S22, 0xfcefa3f8); /* 30 */
GG (ref c, d, a, b, x[k+ 7], S23, 0x676f02d9); /* 31 */
GG (ref b, c, d, a, x[k+12], S24, 0x8d2a4c8a); /* 32 */
/* Round 3 */
HH (ref a, b, c, d, x[k+ 5], S31, 0xfffa3942); /* 33 */
HH (ref d, a, b, c, x[k+ 8], S32, 0x8771f681); /* 34 */
HH (ref c, d, a, b, x[k+11], S33, 0x6d9d6122); /* 35 */
HH (ref b, c, d, a, x[k+14], S34, 0xfde5380c); /* 36 */
HH (ref a, b, c, d, x[k+ 1], S31, 0xa4beea44); /* 37 */
HH (ref d, a, b, c, x[k+ 4], S32, 0x4bdecfa9); /* 38 */
HH (ref c, d, a, b, x[k+ 7], S33, 0xf6bb4b60); /* 39 */
HH (ref b, c, d, a, x[k+10], S34, 0xbebfbc70); /* 40 */
HH (ref a, b, c, d, x[k+13], S31, 0x289b7ec6); /* 41 */
HH (ref d, a, b, c, x[k+ 0], S32, 0xeaa127fa); /* 42 */
HH (ref c, d, a, b, x[k+ 3], S33, 0xd4ef3085); /* 43 */
HH (ref b, c, d, a, x[k+ 6], S34, 0x4881d05); /* 44 */
HH (ref a, b, c, d, x[k+ 9], S31, 0xd9d4d039); /* 45 */
HH (ref d, a, b, c, x[k+12], S32, 0xe6db99e5); /* 46 */
HH (ref c, d, a, b, x[k+15], S33, 0x1fa27cf8); /* 47 */
HH (ref b, c, d, a, x[k+ 2], S34, 0xc4ac5665); /* 48 */
/* Round 4 */
II (ref a, b, c, d, x[k+ 0], S41, 0xf4292244); /* 49 */
II (ref d, a, b, c, x[k+ 7], S42, 0x432aff97); /* 50 */
II (ref c, d, a, b, x[k+14], S43, 0xab9423a7); /* 51 */
II (ref b, c, d, a, x[k+ 5], S44, 0xfc93a039); /* 52 */
II (ref a, b, c, d, x[k+12], S41, 0x655b59c3); /* 53 */
II (ref d, a, b, c, x[k+ 3], S42, 0x8f0ccc92); /* 54 */
II (ref c, d, a, b, x[k+10], S43, 0xffeff47d); /* 55 */
II (ref b, c, d, a, x[k+ 1], S44, 0x85845dd1); /* 56 */
II (ref a, b, c, d, x[k+ 8], S41, 0x6fa87e4f); /* 57 */
II (ref d, a, b, c, x[k+15], S42, 0xfe2ce6e0); /* 58 */
II (ref c, d, a, b, x[k+ 6], S43, 0xa3014314); /* 59 */
II (ref b, c, d, a, x[k+13], S44, 0x4e0811a1); /* 60 */
II (ref a, b, c, d, x[k+ 4], S41, 0xf7537e82); /* 61 */
II (ref d, a, b, c, x[k+11], S42, 0xbd3af235); /* 62 */
II (ref c, d, a, b, x[k+ 2], S43, 0x2ad7d2bb); /* 63 */
II (ref b, c, d, a, x[k+ 9], S44, 0xeb86d391); /* 64 */
A+=a;
B+=b;
C+=c;
D+=d;
}
return new UInt32[]{A,B,C,D};
}
public static byte[] MD5Array(byte[] input){
MD5_Init();
UInt32[] block = MD5_Append(input);
UInt32[] bits = MD5_Trasform(block);
/* Encodes bits (UInt32[]) into output (byte[]). Assumes len is
* a multiple of 4.
*/
byte[] output=new byte[bits.Length*4];
for(int i=0,j=0;i
output[j+1] = (byte)((bits[i] >>8) & 0xff);
output[j+2] = (byte)((bits[i] >>16) & 0xff);
output[j+3] = (byte)((bits[i] >>24) & 0xff);
}
return output;
}
public static string ArrayToHexString(byte[] array,bool uppercase){
string hexString="";
string format="x2";
if(uppercase){
format="X2";
}
foreach(byte b in array){
hexString += b.ToString(format);
}
return hexString;
}
public static string MDString(string message){
char[] c = message.ToCharArray();
byte[] b = new byte[c.Length];
for(int i=0;i
}
byte[] digest = MD5Array(b);
return ArrayToHexString(digest,false);
}
public static string MDFile(string fileName){
FileStream fs=File.Open(fileName,FileMode.Open,FileAccess.Read);
byte[] array=new byte[fs.Length];
fs.Read(array,0,(int)fs.Length);
byte[] digest = MD5Array(array);
fs.Close();
return ArrayToHexString(digest,false);
}
public static string Test(string message){
return "rnMD5 (""+message+"") = " + MD5.MDString(message);
}
public static string TestSuite(){
string s = "";
s+=Test("");
s+=Test("a");
s+=Test("abc");
s+=Test("message digest");
s+=Test("abcdefghijklmnopqrstuvwxyz");
s+=Test("ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789");
s+=Test("12345678901234567890123456789012345678901234567890123456789012345678901234567890");
return s;
}
}
原文链接:http://www.itgoogle.com/web/show_1260.html