Java实现MD5加密算法详解

MD5摘要算法源码（java版） 
 
作者：admin    文章来源：本站收集    点击数：94    更新时间：2007-6-29     
 
public class MD5 {
    private 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 static final int S11 = 7;
    private static final int S12 = 12;
    private static final int S13 = 17;
    private static final int S14 = 22;
    private static final int S21 = 5;
    private static final int S22 = 9;
    private static final int S23 = 14;
    private static final int S24 = 20;
    private static final int S31 = 4;
    private static final int S32 = 11;
    private static final int S33 = 16;
    private static final int S34 = 23;
    private static final int S41 = 6;
    private static final int S42 = 10;
    private static final int S43 = 15;
    private static final int S44 = 21;
    private long[] state = new long[4]; // state(ABCD)
    private long[] count = new long[2]; // number of bits, modulo 2^64
    private byte[] buffer = new byte[64]; // input buffer
    private String digestHexStr;

    private byte[] digest = new byte[16]; 
    public MD5() {
        md5Init();

        return;
    }

    public String getMD5ofString(byte[] inbuf, int buflen) {
        getMD5ofByte(inbuf, buflen);
        digestHexStr = "";

        for (int i = 0; i < 16; i++) {
            digestHexStr += byteHEX(digest[i]);
        }

        return digestHexStr;
    }

    public byte[] getMD5ofByte(byte[] inbuf, int buflen) {
        md5Init();
        md5Update(inbuf, buflen);
        md5Final();

        return digest;
    }

    private void md5Init() {
        count[0] = 0L;
        count[1] = 0L;
        state[0] = 0x67452301L;