MD4加密java算法

网上找了好久，太费劲，所以干脆记录下。

package com.xinhua.util;

public class MD4 {

private static int A, B, C, D;

private static int X[] = new int[16];

private static int F(int X, int Y, int Z) {
return (X & Y) | ((~X) & Z);
}

private static int G(int X, int Y, int Z) {
return (X & Y) | (X & Z) | (Y & Z);
}

private static int H(int X, int Y, int Z) {
return X ^ Y ^ Z;
}

private static int lshift(int x, int s) {
if (s == 0) {
return x;
}
return (((x << s) & 0xFFFFFFFF) | ((x >> (32 - s)) & (0x7FFFFFFF >> (31 - s))));
}

private static int ROUND1(int a, int b, int c, int d, int k, int s) {
return (lshift(a + F(b, c, d) + X[k], s));
}

private static int ROUND2(int a, int b, int c, int d, int k, int s) {
return (lshift(a + G(b, c, d) + X[k] + (int) 0x5A827999, s));
}

private static int ROUND3(int a, int b, int c, int d, int k, int s) {
return (lshift(a + H(b, c, d) + X[k] + (int) 0x6ED9EBA1, s));
}

public static void mdfour64(int M[]) {
int j;
int AA, BB, CC, DD;

for (j = 0; j < 16; j++) {
X[j] = M[j];
}

AA = A;
BB = B;
CC = C;
DD = D;

A = ROUND1(A, B, C, D, 0, 3);
D = ROUND1(D, A, B, C, 1, 7);
C = ROUND1(C, D, A, B, 2, 11);
B = ROUND1(B, C, D, A, 3, 19);
A = ROUND1(A, B, C, D, 4, 3);
D = ROUND1(D, A, B, C, 5, 7);
C = ROUND1(C, D, A, B, 6, 11);
B = ROUND1(B, C, D, A, 7, 19);
A = ROUND1(A, B, C, D, 8, 3);
D = ROUND1(D, A, B, C, 9, 7);
C = ROUND1(C, D, A, B, 10, 11);
B = ROUND1(B, C, D, A, 11, 19);
A = ROUND1(A, B, C, D, 12, 3);
D = ROUND1(D, A, B, C, 13, 7);
C = ROUND1(C, D, A, B, 14, 11);
B = ROUND1(B, C, D, A, 15, 19);

A = ROUND2(A, B, C, D, 0, 3);
D = ROUND2(D, A, B, C, 4, 5);
C = ROUND2(C, D, A, B, 8, 9);
B = ROUND2(B, C, D, A, 12, 13);
A = ROUND2(A, B, C, D, 1, 3);
D = ROUND2(D, A, B, C, 5, 5);
C = ROUND2(C, D, A, B, 9, 9);
B = ROUND2(B, C, D, A, 13, 13);
A = ROUND2(A, B, C, D, 2, 3);
D = ROUND2(D, A, B, C, 6, 5);
C = ROUND2(C, D, A, B, 10, 9);
B = ROUND2(B, C, D, A, 14, 13);
A = ROUND2(A, B, C, D, 3, 3);
D = ROUND2(D, A, B, C, 7, 5);
C = ROUND2(C, D, A, B, 11, 9);
B = ROUND2(B, C, D, A, 15, 13);

A = ROUND3(A, B, C, D, 0, 3);
D = ROUND3(D, A, B, C, 8, 9);
C = ROUND3(C, D, A, B, 4, 11);
B = ROUND3(B, C, D, A, 12, 15);
A = ROUND3(A, B, C, D, 2, 3);
D = ROUND3(D, A, B, C, 10, 9);
C = ROUND3(C, D, A, B, 6, 11);
B = ROUND3(B, C, D, A, 14, 15);
A = ROUND3(A, B, C, D, 1, 3);
D = ROUND3(D, A, B, C, 9, 9);
C = ROUND3(C, D, A, B, 5, 11);
B = ROUND3(B, C, D, A, 13, 15);
A = ROUND3(A, B, C, D, 3, 3);
D = ROUND3(D, A, B, C, 11, 9);
C = ROUND3(C, D, A, B, 7, 11);
B = ROUND3(B, C, D, A, 15, 15);

A += AA;
B += BB;
C += CC;
D += DD;

A &= 0xFFFFFFFF;
B &= 0xFFFFFFFF;
C &= 0xFFFFFFFF;
D &= 0xFFFFFFFF;
}

public static void copy64(int M[], byte in[], int offset) {
int i;
for (i = 0; i < 16; i++) {
M[i] = ((in[offset + i * 4 + 3] << 24) & 0xFF000000)
| ((in[offset + i * 4 + 2] << 16) & 0xFF0000)
| ((in[offset + i * 4 + 1] << 8) & 0xFF00)
| (((int) in[offset + i * 4 + 0]) & 0xFF);
}
}

public static void copy64(int M[], byte in[]) {
copy64(M, in, 0);
}

public static void copy4(byte out[], int offset, int x) {
out[offset] = (byte) (x & 0xFF);
out[1 + offset] = (byte) ((x >> 8) & 0xFF);
out[2 + offset] = (byte) ((x >> 16) & 0xFF);
out[3 + offset] = (byte) ((x >> 24) & 0xFF);
}

public static byte[] mdfour(byte in[]) {
byte out[] = new byte[16];
byte buf[] = new byte[128];
int n = in.length;
int M[] = new int[16];
int b = n * 8;
int i;
int offset;

A = 0x67452301;
B = 0xefcdab89;
C = 0x98badcfe;
D = 0x10325476;

offset = 0;
while (n > 64) {
copy64(M, in, offset);
mdfour64(M);
offset += 64;
n -= 64;
}

for (i = 0; i < 128; i++) {
buf[i] = (i + offset < in.length) ? in[offset + i] : 0;
}
buf
= (byte) 0x80;

if (n <= 55) {
copy4(buf, 56, b);
copy64(M, buf);
mdfour64(M);
} else {
copy4(buf, 120, b);
copy64(M, buf);
mdfour64(M);
copy64(M, buf, 64);
mdfour64(M);
}

for (i = 0; i < 128; i++) {
buf[i] = 0;
}
copy64(M, buf);

copy4(out, 0, A);
copy4(out, 4, B);
copy4(out, 8, C);
copy4(out, 12, D);

A = B = C = D = 0;
return out;
}

private static final char[] HEX_DIGITS = { '0', '1', '2', '3', '4', '5',
'6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f' };

public static String toHexString(byte[] b) {
return toHexString(b, 0, b.length);
}

public static String toHexString(byte[] b, int off, int len) {
char[] buf = new char[len * 2];
for (int i = 0, j = 0, k; i < len;) {
k = b[off + i++];
buf[j++] = HEX_DIGITS[(k >>> 4) & 0x0F];
buf[j++] = HEX_DIGITS[k & 0x0F];
}
return new String(buf);
}

public static String getMD4ofStr(String s) {
return toHexString(mdfour(s.getBytes()));
}

public static void main(String[] args) {
System.out.println(getMD4ofStr(""));
System.out.println(getMD4ofStr("a"));
System.out.println(getMD4ofStr("abc"));
System.out.println(getMD4ofStr("message digest"));
System.out.println(getMD4ofStr("abcdefghijklmnopqrstuvwxyz"));
System.out.println(getMD4ofStr("ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"));
System.out.println(getMD4ofStr("123000"));
}

}