JAVA ME 实现MD5算法 【整理】
http://www.3geye.net/?3/viewspace-280

上面是原文地址

看了下网络高手写的代码我顺便整理下。供大家学习，

package com.gggeye.util;

/**
?* MD5Util 算法的实现类，此代码为网上摘录，版权归对方所有，我做的工作只是整理
?日期 2007-10-1
?*
?* @author wuhua
?*???????? <p>
?*???????? <b>MSN </b> gggeye@hotmail.com
?*???????? <p>
?*???????? <b>EMAIL</b> gooogledev@gmail.com
?*???????? </p>
?*???????? <p>
?*???????? 网站支持 <a href="http://www.3geye.net">http://www.3geye.net</a>
?*???????? </p>
?*???????? <p>
?*???????? 网站论坛 <a href="http://www.3geye.net/bbs">http://www.3geye.net/bbs</a>
?*???????? </p>
?*???????? <p>
?*???????? wuhua的博客 <a href="http://wuhua.3geye.net">http://wuhua.3geye.net</a>
?*???????? </p>
?*/
public class MD5Util {

??? 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 char Hex[] = { '0', '1', '2', '3', '4', '5', '6', '7', '8',
??? ??? ??? '9', 'A', 'B', 'C', 'D', 'E', 'F' };
??? 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 };
??? private long state[];
??? private long count[];
??? private byte buffer[];
??? public String digestHexStr;
??? private byte digest[];
??? ?

??? public String getMD5ofStr(String s) {// 返回MD5串；
??? ??? int i;
??? ??? md5Init();
??? ??? md5Update(s.getBytes(), s.length());
??? ??? md5Final();
??? ??? digestHexStr = "";
??? ??? for (i = 0; i < 16; i++)
??? ??? ??? digestHexStr = digestHexStr + byteHEX(digest[i]);
??? ??? return digestHexStr;
??? }

??? public MD5Util() {
??? ??? state = new long[4];
??? ??? count = new long[2];
??? ??? buffer = new byte[64];
??? ??? digest = new byte[16];
??? ??? md5Init();
??? }

??? private void md5Init() {// 初始化部分变量；
??? ??? count[0] = 0L;
??? ??? count[1] = 0L;
??? ??? state[0] = 0x67452301L;
??? ??? state[1] = 0xefcdab89L;
??? ??? state[2] = 0x98badcfeL;
??? ??? state[3] = 0x10325476L;
??? }

??? private long F(long l, long l1, long l2) {
??? ??? return l & l1 | ~l & l2;
??? }

??? private long G(long l, long l1, long l2) {
??? ??? return l & l2 | l1 & ~l2;
??? }

??? private long H(long l, long l1, long l2) {
??? ??? return l ^ l1 ^ l2;
??? }

??? private long I(long l, long l1, long l2) {
??? ??? return l1 ^ (l | ~l2);
??? }

??? private long FF(long l, long l1, long l2, long l3, long l4, long l5, long l6) {
??? ??? l += F(l1, l2, l3) + l4 + l6;
??? ??? l = (int) l << (int) l5 | (int) l >>> (int) (32L - l5);
??? ??? l += l1;
??? ??? return l;
??? }

??? private long GG(long l, long l1, long l2, long l3, long l4, long l5, long l6) {
??? ??? l += G(l1, l2, l3) + l4 + l6;
??? ??? l = (int) l << (int) l5 | (int) l >>> (int) (32L - l5);
??? ??? l += l1;
??? ??? return l;
??? }

??? private long HH(long l, long l1, long l2, long l3, long l4, long l5, long l6) {
??? ??? l += H(l1, l2, l3) + l4 + l6;
??? ??? l = (int) l << (int) l5 | (int) l >>> (int) (32L - l5);
??? ??? l += l1;
??? ??? return l;
??? }

??? private long II(long l, long l1, long l2, long l3, long l4, long l5, long l6) {
??? ??? l += I(l1, l2, l3) + l4 + l6;
??? ??? l = (int) l << (int) l5 | (int) l >>> (int) (32L - l5);
??? ??? l += l1;
??? ??? return l;
??? }

??? private void md5Update(byte abyte0[], int i) {// 补位操作，abyte0为需要进行MD5加密的字符串，i为字符串长度；
??? ??? byte abyte1[] = new byte[64];
??? ??? int k = (int) (count[0] >>> 3) & 0x3f;
??? ??? if ((count[0] += i << 3) < (long) (i << 3))
??? ??? ??? count[1]++;
??? ??? count[1] += i >>> 29;
??? ??? int l = 64 - k;
??? ??? int j;
??? ??? if (i >= l) {
??? ??? ??? md5Memcpy(buffer, abyte0, k, 0, l);
??? ??? ??? md5Transform(buffer);
??? ??? ??? for (j = l; j + 63 < i; j += 64) {
??? ??? ??? ??? md5Memcpy(abyte1, abyte0, 0, j, 64);
??? ??? ??? ??? md5Transform(abyte1);
??? ??? ??? }
??? ??? ??? k = 0;
??? ??? } else {
??? ??? ??? j = 0;
??? ??? }
??? ??? md5Memcpy(buffer, abyte0, k, j, i - j);
??? }

??? private void md5Final() {// 最终处理，将得到的128位（16字节）MD5码存放在digest数组中
??? ??? byte abyte0[] = new byte[8];
??? ??? encode(abyte0, count, 8);
??? ??? int i = (int) (count[0] >>> 3) & 0x3f;
??? ??? int j = i >= 56 ? 120 - i : 56 - i;
??? ??? md5Update(PADDING, j);
??? ??? md5Update(abyte0, 8);
??? ??? encode(digest, state, 16);
??? }

??? private void md5Memcpy(byte abyte0[], byte abyte1[], int i, int j, int k) {
??? ??? for (int l = 0; l < k; l++)
??? ??? ??? abyte0[i + l] = abyte1[j + l];
??? }

??? private void md5Transform(byte abyte0[]) {
??? ??? long l = state[0];
??? ??? long l1 = state[1];
??? ??? long l2 = state[2];
??? ??? long l3 = state[3];
??? ??? long al[] = new long[16];
??? ??? decode(al, abyte0, 64);
??? ??? l = FF(l, l1, l2, l3, al[0], 7L, 0xd76aa478L);
??? ??? l3 = FF(l3, l, l1, l2, al[1], 12L, 0xe8c7b756L);
??? ??? l2 = FF(l2, l3, l, l1, al[2], 17L, 0x242070dbL);
??? ??? l1 = FF(l1, l2, l3, l, al[3], 22L, 0xc1bdceeeL);
??? ??? l = FF(l, l1, l2, l3, al[4], 7L, 0xf57c0fafL);
??? ??? l3 = FF(l3, l, l1, l2, al[5], 12L, 0x4787c62aL);
??? ??? l2 = FF(l2, l3, l, l1, al[6], 17L, 0xa8304613L);
??? ??? l1 = FF(l1, l2, l3, l, al[7], 22L, 0xfd469501L);
??? ??? l = FF(l, l1, l2, l3, al[8], 7L, 0x698098d8L);
??? ??? l3 = FF(l3, l, l1, l2, al[9], 12L, 0x8b44f7afL);
??? ??? l2 = FF(l2, l3, l, l1, al[10], 17L, 0xffff5bb1L);
??? ??? l1 = FF(l1, l2, l3, l, al[11], 22L, 0x895cd7beL);
??? ??? l = FF(l, l1, l2, l3, al[12], 7L, 0x6b901122L);
??? ??? l3 = FF(l3, l, l1, l2, al[13], 12L, 0xfd987193L);
??? ??? l2 = FF(l2, l3, l, l1, al[14], 17L, 0xa679438eL);
??? ??? l1 = FF(l1, l2, l3, l, al[15], 22L, 0x49b40821L);
??? ??? l = GG(l, l1, l2, l3, al[1], 5L, 0xf61e2562L);
??? ??? l3 = GG(l3, l, l1, l2, al[6], 9L, 0xc040b340L);
??? ??? l2 = GG(l2, l3, l, l1, al[11], 14L, 0x265e5a51L);
??? ??? l1 = GG(l1, l2, l3, l, al[0], 20L, 0xe9b6c7aaL);
??? ??? l = GG(l, l1, l2, l3, al[5], 5L, 0xd62f105dL);
??? ??? l3 = GG(l3, l, l1, l2, al[10], 9L, 0x2441453L);
??? ??? l2 = GG(l2, l3, l, l1, al[15], 14L, 0xd8a1e681L);
??? ??? l1 = GG(l1, l2, l3, l, al[4], 20L, 0xe7d3fbc8L);
??? ??? l = GG(l, l1, l2, l3, al[9], 5L, 0x21e1cde6L);
??? ??? l3 = GG(l3, l, l1, l2, al[14], 9L, 0xc33707d6L);
??? ??? l2 = GG(l2, l3, l, l1, al[3], 14L, 0xf4d50d87L);
??? ??? l1 = GG(l1, l2, l3, l, al[8], 20L, 0x455a14edL);
??? ??? l = GG(l, l1, l2, l3, al[13], 5L, 0xa9e3e905L);
??? ??? l3 = GG(l3, l, l1, l2, al[2], 9L, 0xfcefa3f8L);
??? ??? l2 = GG(l2, l3, l, l1, al[7], 14L, 0x676f02d9L);
??? ??? l1 = GG(l1, l2, l3, l, al[12], 20L, 0x8d2a4c8aL);
??? ??? l = HH(l, l1, l2, l3, al[5], 4L, 0xfffa3942L);
??? ??? l3 = HH(l3, l, l1, l2, al[8], 11L, 0x8771f681L);
??? ??? l2 = HH(l2, l3, l, l1, al[11], 16L, 0x6d9d6122L);
??? ??? l1 = HH(l1, l2, l3, l, al[14], 23L, 0xfde5380cL);
??? ??? l = HH(l, l1, l2, l3, al[1], 4L, 0xa4beea44L);
??? ??? l3 = HH(l3, l, l1, l2, al[4], 11L, 0x4bdecfa9L);
??? ??? l2 = HH(l2, l3, l, l1, al[7], 16L, 0xf6bb4b60L);
??? ??? l1 = HH(l1, l2, l3, l, al[10], 23L, 0xbebfbc70L);
??? ??? l = HH(l, l1, l2, l3, al[13], 4L, 0x289b7ec6L);
??? ??? l3 = HH(l3, l, l1, l2, al[0], 11L, 0xeaa127faL);
??? ??? l2 = HH(l2, l3, l, l1, al[3], 16L, 0xd4ef3085L);
??? ??? l1 = HH(l1, l2, l3, l, al[6], 23L, 0x4881d05L);
??? ??? l = HH(l, l1, l2, l3, al[9], 4L, 0xd9d4d039L);
??? ??? l3 = HH(l3, l, l1, l2, al[12], 11L, 0xe6db99e5L);
??? ??? l2 = HH(l2, l3, l, l1, al[15], 16L, 0x1fa27cf8L);
??? ??? l1 = HH(l1, l2, l3, l, al[2], 23L, 0xc4ac5665L);
??? ??? l = II(l, l1, l2, l3, al[0], 6L, 0xf4292244L);
??? ??? l3 = II(l3, l, l1, l2, al[7], 10L, 0x432aff97L);
??? ??? l2 = II(l2, l3, l, l1, al[14], 15L, 0xab9423a7L);
??? ??? l1 = II(l1, l2, l3, l, al[5], 21L, 0xfc93a039L);
??? ??? l = II(l, l1, l2, l3, al[12], 6L, 0x655b59c3L);
??? ??? l3 = II(l3, l, l1, l2, al[3], 10L, 0x8f0ccc92L);
??? ??? l2 = II(l2, l3, l, l1, al[10], 15L, 0xffeff47dL);
??? ??? l1 = II(l1, l2, l3, l, al[1], 21L, 0x85845dd1L);
??? ??? l = II(l, l1, l2, l3, al[8], 6L, 0x6fa87e4fL);
??? ??? l3 = II(l3, l, l1, l2, al[15], 10L, 0xfe2ce6e0L);
??? ??? l2 = II(l2, l3, l, l1, al[6], 15L, 0xa3014314L);
??? ??? l1 = II(l1, l2, l3, l, al[13], 21L, 0x4e0811a1L);
??? ??? l = II(l, l1, l2, l3, al[4], 6L, 0xf7537e82L);
??? ??? l3 = II(l3, l, l1, l2, al[11], 10L, 0xbd3af235L);
??? ??? l2 = II(l2, l3, l, l1, al[2], 15L, 0x2ad7d2bbL);
??? ??? l1 = II(l1, l2, l3, l, al[9], 21L, 0xeb86d391L);
??? ??? state[0] += l;
??? ??? state[1] += l1;
??? ??? state[2] += l2;
??? ??? state[3] += l3;
??? }

??? private void encode(byte abyte0[], long al[], int i) {// 转换函数，将al中long型的变量输出到byte型的数组abyte0中，
??? ??? // 低位字节在前，高位字节在后；
??? ??? int j = 0;
??? ??? for (int k = 0; k < i; k += 4) {
??? ??? ??? abyte0[k] = (byte) (int) (al[j] & 255L);
??? ??? ??? abyte0[k + 1] = (byte) (int) (al[j] >>> 8 & 255L);
??? ??? ??? abyte0[k + 2] = (byte) (int) (al[j] >>> 16 & 255L);
??? ??? ??? abyte0[k + 3] = (byte) (int) (al[j] >>> 24 & 255L);
??? ??? ??? j++;
??? ??? }
??? }

??? private void decode(long al[], byte abyte0[], int i) {
??? ??? int j = 0;
??? ??? for (int k = 0; k < i; k += 4) {
??? ??? ??? al[j] = b2iu(abyte0[k]) | b2iu(abyte0[k + 1]) << 8
??? ??? ??? ??? ??? | b2iu(abyte0[k + 2]) << 16 | b2iu(abyte0[k + 3]) << 24;
??? ??? ??? j++;
??? ??? }
??? }

??? public static long b2iu(byte byte0) {
??? ??? return byte0 >= 0 ? byte0 : byte0 & 0xff;
??? }

??? public static String byteHEX(byte byte0) {// 字节到十六进制的ASCII码转换
??? ??? char ac[] = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A',
??? ??? ??? ??? 'B', 'C', 'D', 'E', 'F' };
??? ??? char ac1[] = new char[2];
??? ??? ac1[0] = ac[byte0 >>> 4 & 0xf];
??? ??? ac1[1] = ac[byte0 & 0xf];
??? ??? String s = new String(ac1);
??? ??? return s;
??? }

??? public static String toMD5(String s) {
??? ??? MD5Util md5 = new MD5Util();
??? ??? return md5.getMD5ofStr(s);
??? }
}