import java.lang.reflect.*;
/**
* MD5 算法的Java Bean
* MD5 类实现了RSA Data Security, Inc.在提交给IETF 的RFC1321中的MD5 message-digest 算法。
*/
public class MD5
{
//下面这些S11-S44实际上是一个4*4的矩阵，在原始的C实现中是用#define 实现的，这里把它们实现成为static final是表示了只读，切能在同一个进程空间内的多个Instance间共享
static final int S11 = 7;
static final int S12 = 12;
static final int S13 = 17;
static final int S14 = 22;
static final int S21 = 5;
static final int S22 = 9;
static final int S23 = 14;
static final int S24 = 20;
static final int S31 = 4;
static final int S32 = 11;
static final int S33 = 16;
static final int S34 = 23;
static final int S41 = 6;
static final int S42 = 10;
static final int S43 = 15;
static final int S44 = 21;
static final byte[] PADDING =
{ -128,0,0,0,0,0,0,0,0,
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};
//下面的三个成员是MD5计算过程中用到的3个核心数据，在原始的C实现中被定义到MD5_CTX结构中
private long[] state = new long[4]; // state (ABCD)
private long[] count = new long[2]; // number of bits, modulo 2^64 (lsb first)
private byte[] buffer = new byte[64]; // input buffer
//digestHexStr是MD5的唯一一个公共成员，是最新一次计算结果的16进制ASCII表示.
public String digestHexStr;
//digest,是最新一次计算结果的2进制内部表示，表示128bit的MD5值.
private byte[] digest = new byte[16];
//getMD5ofStr是类MD5最主要的公共方法，入口参数是你想要进行MD5变换的字符串返回的是变换完的结果，这个结果是从公共成员digestHexStr取得的．
public String getMD5ofStr(String inbuf)
{
md5Init();
md5Update(inbuf.getBytes(),inbuf.length());
md5Final();
digestHexStr = "";
for(int i = 0;i < 16;i++)
{
digestHexStr += byteHEX(digest[i]);
}
return digestHexStr;
}
// 这是MD5这个类的标准构造函数，JavaBean要求有一个public的并且没有参数的构造函数
public MD5()
{
md5Init();
return;
}
//md5Init是一个初始化函数，初始化核心变量，装入标准的幻数
private void md5Init()
{
count[0] = 0L;
count[1] = 0L;
//Load magic initialization constants.
state[0] = 0x67452301L;
state[1] = 0xefcdab89L;
state[2] = 0x98badcfeL;
state[3] = 0x10325476L;
return;
}
/* F, G, H ,I 是4个基本的MD5函数，在原始的MD5的C实现中，由于它们是简单的位运算，可能出于效率的考虑把它们实现成了宏，在java中，我们把它们实现成了private方法，名字保持了原来C中的。 */
private long F(long x,long y,long z)
{
return(x & y) | ((~x) & z);
}
private long G(long x,long y,long z)
{
return(x & z) | (y & (~z));
}
private long H(long x,long y,long z)
{
return x ^ y ^ z;
}
private long I(long x,long y,long z)
{
return y ^ (x | (~z));
}
/*
FF,GG,HH和II将调用F,G,H,I进行近一步变换FF, GG, HH, and II transformations for rounds 1, 2, 3, and 4.
Rotation is separate from addition to prevent recomputation.
*/
private long FF(long a,long b,long c,long d,long x,long s,long ac)
{
a += F(b,c,d) + x + ac;
a = ((int)a << s) | ((int)a >>> (32 - s));
a += b;
return a;
}
private long GG(long a,long b,long c,long d,long x,long s,long ac)
{
a += G(b,c,d) + x + ac;
a = ((int)a << s) | ((int)a >>> (32 - s));
a += b;
return a;
}
private long HH(long a,long b,long c,long d,long x,long s,long ac)
{
a += H(b,c,d) + x + ac;
a = ((int)a << s) | ((int)a >>> (32 - s));
a += b;
return a;
}
private long II(long a,long b,long c,long d,long x,long s,long ac)
{
a += I(b,c,d) + x + ac;
a = ((int)a << s) | ((int)a >>> (32 - s));
a += b;
return a;
}
//md5Update是MD5的主计算过程，inbuf是要变换的字节串，inputlen是长度，这个函数由getMD5ofStr调用，调用之前需要调用md5init，因此把它设计成private的
private void md5Update(byte[] inbuf,int inputLen)
{
int i,index,partLen;
byte[] block = new byte[64];
index = (int)(count[0] >>> 3) & 0x3F;
//Update number of bits
if((count[0] += (inputLen << 3)) < (inputLen << 3))
{
count[1]++;
}
count[1] += (inputLen >>> 29);
partLen = 64 - index;
//Transform as many times as possible.
if(inputLen >= partLen)
{
md5Memcpy(buffer,inbuf,index,0,partLen);
md5Transform(buffer);
for(i = partLen;i + 63 < inputLen;i += 64)
{
md5Memcpy(block,inbuf,0,i,64);
md5Transform(block);
}
index = 0;
}
else
{
i = 0;
}
//Buffer remaining input
md5Memcpy(buffer,inbuf,index,i,inputLen - i);
}
//md5Final整理和填写输出结果
private void md5Final()
{
byte[] bits = new byte[8];
int index,padLen;
//Save number of bits
Encode(bits,count,8);
//Pad out to 56 mod 64.
index = (int)(count[0] >>> 3) & 0x3f;
padLen = (index < 56) ? (56 - index) : (120 - index);
md5Update(PADDING,padLen);
//Append length (before padding)
md5Update(bits,8);
//Store state in digest
Encode(digest,state,16);
}
//md5Memcpy是一个内部使用的byte数组的块拷贝函数，从input的inpos开始把len长度的字节拷贝到output的outpos位置开始
private void md5Memcpy(byte[] output,byte[] input,int outpos,int inpos,int len)
{
int i;
for(i = 0;i < len;i++)
{
output[outpos + i] = input[inpos + i];
}
}
//md5Transform是MD5核心变换程序，有md5Update调用，block是分块的原始字节
private void md5Transform(byte block[])
{
long a = state[0],b = state[1],c = state[2],d = state[3];
long[] x = new long[16];
Decode(x,block,64);
/* Round 1 */
a = FF(a,b,c,d,x[0],S11,0xd76aa478L); /* 1 */
d = FF(d,a,b,c,x[1],S12,0xe8c7b756L); /* 2 */
c = FF(c,d,a,b,x[2],S13,0x242070dbL); /* 3 */
b = FF(b,c,d,a,x[3],S14,0xc1bdceeeL); /* 4 */
a = FF(a,b,c,d,x[4],S11,0xf57c0fafL); /* 5 */
d = FF(d,a,b,c,x[5],S12,0x4787c62aL); /* 6 */
c = FF(c,d,a,b,x[6],S13,0xa8304613L); /* 7 */
b = FF(b,c,d,a,x[7],S14,0xfd469501L); /* 8 */
a = FF(a,b,c,d,x[8],S11,0x698098d8L); /* 9 */
d = FF(d,a,b,c,x[9],S12,0x8b44f7afL); /* 10 */
c = FF(c,d,a,b,x[10],S13,0xffff5bb1L); /* 11 */
b = FF(b,c,d,a,x[11],S14,0x895cd7beL); /* 12 */
a = FF(a,b,c,d,x[12],S11,0x6b901122L); /* 13 */
d = FF(d,a,b,c,x[13],S12,0xfd987193L); /* 14 */
c = FF(c,d,a,b,x[14],S13,0xa679438eL); /* 15 */
b = FF(b,c,d,a,x[15],S14,0x49b40821L); /* 16 */
/* Round 2 */
a = GG(a,b,c,d,x[1],S21,0xf61e2562L); /* 17 */
d = GG(d,a,b,c,x[6],S22,0xc040b340L); /* 18 */
c = GG(c,d,a,b,x[11],S23,0x265e5a51L); /* 19 */
b = GG(b,c,d,a,x[0],S24,0xe9b6c7aaL); /* 20 */
a = GG(a,b,c,d,x[5],S21,0xd62f105dL); /* 21 */
d = GG(d,a,b,c,x[10],S22,0x2441453L); /* 22 */
c = GG(c,d,a,b,x[15],S23,0xd8a1e681L); /* 23 */
b = GG(b,c,d,a,x[4],S24,0xe7d3fbc8L); /* 24 */
a = GG(a,b,c,d,x[9],S21,0x21e1cde6L); /* 25 */
d = GG(d,a,b,c,x[14],S22,0xc33707d6L); /* 26 */
c = GG(c,d,a,b,x[3],S23,0xf4d50d87L); /* 27 */
b = GG(b,c,d,a,x[8],S24,0x455a14edL); /* 28 */
a = GG(a,b,c,d,x[13],S21,0xa9e3e905L); /* 29 */
d = GG(d,a,b,c,x[2],S22,0xfcefa3f8L); /* 30 */
c = GG(c,d,a,b,x[7],S23,0x676f02d9L); /* 31 */
b = GG(b,c,d,a,x[12],S24,0x8d2a4c8aL); /* 32 */
/* Round 3 */
a = HH(a,b,c,d,x[5],S31,0xfffa3942L); /* 33 */
d = HH(d,a,b,c,x[8],S32,0x8771f681L); /* 34 */
c = HH(c,d,a,b,x[11],S33,0x6d9d6122L); /* 35 */
b = HH(b,c,d,a,x[14],S34,0xfde5380cL); /* 36 */
a = HH(a,b,c,d,x[1],S31,0xa4beea44L); /* 37 */
d = HH(d,a,b,c,x[4],S32,0x4bdecfa9L); /* 38 */
c = HH(c,d,a,b,x[7],S33,0xf6bb4b60L); /* 39 */
b = HH(b,c,d,a,x[10],S34,0xbebfbc70L); /* 40 */
a = HH(a,b,c,d,x[13],S31,0x289b7ec6L); /* 41 */
d = HH(d,a,b,c,x[0],S32,0xeaa127faL); /* 42 */
c = HH(c,d,a,b,x[3],S33,0xd4ef3085L); /* 43 */
b = HH(b,c,d,a,x[6],S34,0x4881d05L); /* 44 */
a = HH(a,b,c,d,x[9],S31,0xd9d4d039L); /* 45 */
d = HH(d,a,b,c,x[12],S32,0xe6db99e5L); /* 46 */
c = HH(c,d,a,b,x[15],S33,0x1fa27cf8L); /* 47 */
b = HH(b,c,d,a,x[2],S34,0xc4ac5665L); /* 48 */
/* Round 4 */
a = II(a,b,c,d,x[0],S41,0xf4292244L); /* 49 */
d = II(d,a,b,c,x[7],S42,0x432aff97L); /* 50 */
c = II(c,d,a,b,x[14],S43,0xab9423a7L); /* 51 */
b = II(b,c,d,a,x[5],S44,0xfc93a039L); /* 52 */
a = II(a,b,c,d,x[12],S41,0x655b59c3L); /* 53 */
d = II(d,a,b,c,x[3],S42,0x8f0ccc92L); /* 54 */
c = II(c,d,a,b,x[10],S43,0xffeff47dL); /* 55 */
b = II(b,c,d,a,x[1],S44,0x85845dd1L); /* 56 */
a = II(a,b,c,d,x[8],S41,0x6fa87e4fL); /* 57 */
d = II(d,a,b,c,x[15],S42,0xfe2ce6e0L); /* 58 */
c = II(c,d,a,b,x[6],S43,0xa3014314L); /* 59 */
b = II(b,c,d,a,x[13],S44,0x4e0811a1L); /* 60 */
a = II(a,b,c,d,x[4],S41,0xf7537e82L); /* 61 */
d = II(d,a,b,c,x[11],S42,0xbd3af235L); /* 62 */
c = II(c,d,a,b,x[2],S43,0x2ad7d2bbL); /* 63 */
b = II(b,c,d,a,x[9],S44,0xeb86d391L); /* 64 */
state[0] += a;
state[1] += b;
state[2] += c;
state[3] += d;
}
//Encode把long数组按顺序拆成byte数组，因为java的long类型是64bit的，只拆低32bit，以适应原始C实现的用途
private void Encode(byte[] output,long[] input,int len)
{
int i,j;
for(i = 0,j = 0;j < len;i++,j += 4)
{
output[j] = (byte)(input[i] & 0xffL);
output[j + 1] = (byte)((input[i] >>> 8) & 0xffL);
output[j + 2] = (byte)((input[i] >>> 16) & 0xffL);
output[j + 3] = (byte)((input[i] >>> 24) & 0xffL);
}
}
//Decode把byte数组按顺序合成成long数组，因为java的long类型是64bit的，只合成低32bit，高32bit清零，以适应原始C实现的用途
private void Decode(long[] output,byte[] input,int len)
{
int i,j;
for(i = 0,j = 0;j < len;i++,j += 4)
{
output[i] = b2iu(input[j]) | (b2iu(input[j + 1]) << 8) | (b2iu(input[j + 2]) << 16) | (b2iu(input[j + 3]) << 24);
}
return;
}
//b2iu是一个把byte按照不考虑正负号的原则的＂升位＂程序，因为java没有unsigned运算
public static long b2iu(byte b)
{
return b < 0 ? b & 0x7F + 128 : b;
}
//byteHEX()，用来把一个byte类型的数转换成十六进制的ASCII表示，因为java中的byte的toString无法实现这一点，我们又没有C语言中的sprintf(outbuf,"%02X",ib)
public static String byteHEX(byte ib)
{
char[] Digit =
{'0','1','2','3','4','5','6','7','8','9',
'A','B','C','D','E','F'};
char[] ob = new char[2];
ob[0] = Digit[(ib >>> 4) & 0X0F];
ob[1] = Digit[ib & 0X0F];
String s = new String(ob);
return s;
}
public static void main(String args[])
{
MD5 m = new MD5();
if(Array.getLength(args) == 0)
{
//如果没有参数，执行标准的Test Suite
System.out.println("MD5 Test suite:");
System.out.println("MD5(\"\"):" + m.getMD5ofStr(""));
System.out.println("MD5(\"16899168\"):" + m.getMD5ofStr("16899168"));//77604D727334C3D1B074DBFC1B5E1B9C
System.out.println("MD5(\"password\"):" + m.getMD5ofStr("password"));//5F4DCC3B5AA765D61D8327DEB882CF99
System.out.println("MD5(\"a\"):" + m.getMD5ofStr("a"));
System.out.println("MD5(\"abc\"):" + m.getMD5ofStr("abc"));
System.out.println("MD5(\"message digest\"):" + m.getMD5ofStr("message digest"));
System.out.println("MD5(\"abcdefghijklmnopqrstuvwxyz\"):" + m.getMD5ofStr("abcdefghijklmnopqrstuvwxyz"));
System.out.println("MD5(\"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789\"):" + m.getMD5ofStr("ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"));
}
else
{
System.out.println("MD5(" + args[0] + ")=" + m.getMD5ofStr(args[0]));
}
}
}