MD5加密

MD5加密是一种国际上比较常用的加密算法

虽然MD5加密算法已经被我国王小云教授给**了，但是对一般的加密需求而言还是足够了的，

首先是MD5加密算法的JAVA实现

package test;

public class MD5 {
	private static MD5 md5;

	private long m_buf[];

	private long m_bits[];

	private byte m_in[];

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

	private MD5() {
		m_buf = new long[4];
		m_bits = new long[2];
		m_in = new byte[64];
	}

	public static MD5 getInstance() {
		if (md5 == null)
			md5 = new MD5();
		return md5;
	}

	public String toDigest(String src) {
		byte digest[] = toDigest(src.getBytes());
		StringBuffer sb = new StringBuffer();
		for (int i = 0; i < digest.length; i++) {
			sb.append(HEX[(digest[i] & 0xff) / 16]);
			sb.append(HEX[(digest[i] & 0xff) % 16]);
		}

		return sb.toString();
	}

	public byte[] toDigest(byte src[]) {
		byte digest[] = new byte[16];
		int len = src.length;
		MD5Init();
		MD5Update(src, len);
		MD5Final(digest);
		return digest;
	}

	private void memset(byte des[], int des_offset, byte dat, int len) {
		for (int i = 0; i < len; i++)
			des[des_offset + i] = dat;

	}

	private void memset(long des[], int des_offset, long dat, int len) {
		for (int i = 0; i < len; i++)
			des[des_offset + i] = dat;

	}

	private void memcpy(byte des[], int des_offset, byte src[], int src_offset,
			int len) {
		for (int i = 0; i < len; i++)
			des[des_offset + i] = src[src_offset + i];

	}

	private long bp2long(byte src[], int offset_lng) {
		long ret = 0L;
		ret = (long) src[offset_lng * 4 + 0] & 255L
				| (long) (src[offset_lng * 4 + 1] << 8) & 65280L
				| (long) (src[offset_lng * 4 + 2] << 16) & 0xff0000L
				| (long) (src[offset_lng * 4 + 3] << 24) & 0xff000000L;
		return ret & 0xffffffffL;
	}

	private void MD5Init() {
		m_buf[0] = 0x67452301L;
		m_buf[1] = 0xefcdab89L;
		m_buf[2] = 0x98badcfeL;
		m_buf[3] = 0x10325476L;
		m_bits[0] = 0L;
		m_bits[1] = 0L;
	}

	private void MD5Update(byte buf[], int len) {
		long t = m_bits[0];
		m_bits[0] = t + (long) (len << 3);
		if (m_bits[0] < t)
			m_bits[1]++;
		m_bits[1] = m_bits[1] + (long) (len >> 29);
		t = t >> 3 & 63L;
		if (t != 0L) {
			long p = t;
			t = (long) 64 - t & 0xffffffffL;
			if ((long) len < t) {
				memcpy(m_in, (int) t, buf, 0, len);
				return;
			}
			memcpy(m_in, (int) t, buf, 0, (int) t);
			MD5Transform();
			len = (int) ((long) len - t);
		}
		for (; len >= 64; len -= 64) {
			memcpy(m_in, 0, buf, (int) t, 64);
			MD5Transform();
			t += 64;
		}

		memcpy(m_in, 0, buf, (int) t, len);
	}

	private void MD5Final(byte digest[]) {
		long count = m_bits[0] >> 3 & 63L;
		m_in[(int) count] = -128;
		long p = count + (long) 1;
		count = (long) 63 - count;
		if (count < (long) 8) {
			memset(m_in, (int) p, (byte) 0, (int) count);
			MD5Transform();
			memset(m_in, 0, (byte) 0, 56);
		} else {
			memset(m_in, (int) p, (byte) 0, (int) (count - (long) 8));
		}
		m_in[56] = (byte) (int) (m_bits[0] & (long) 255);
		m_in[57] = (byte) (int) (m_bits[0] >> 8 & (long) 255);
		m_in[58] = (byte) (int) (m_bits[0] >> 16 & (long) 255);
		m_in[59] = (byte) (int) (m_bits[0] >> 24 & (long) 255);
		m_in[60] = (byte) (int) (m_bits[1] & (long) 255);
		m_in[61] = (byte) (int) (m_bits[1] >> 8 & (long) 255);
		m_in[62] = (byte) (int) (m_bits[1] >> 16 & (long) 255);
		m_in[63] = (byte) (int) (m_bits[1] >> 24 & (long) 255);
		MD5Transform();
		for (int i = 0; i < 4; i++) {
			digest[i * 4 + 0] = (byte) (int) (m_buf[i] & (long) 255);
			digest[i * 4 + 1] = (byte) (int) (m_buf[i] >> 8 & (long) 255);
			digest[i * 4 + 2] = (byte) (int) (m_buf[i] >> 16 & (long) 255);
			digest[i * 4 + 3] = (byte) (int) (m_buf[i] >> 24 & (long) 255);
		}

		MD5Init();
	}

	private long F1(long x, long y, long z) {
		return (z ^ x & (y ^ z)) & 0xffffffffL;
	}

	private long F2(long x, long y, long z) {
		return F1(z, x, y);
	}

	private long F3(long x, long y, long z) {
		return (x ^ y ^ z) & 0xffffffffL;
	}

	private long F4(long x, long y, long z) {
		return (y ^ (x | z ^ 0L - 1L)) & 0xffffffffL;
	}

	private long MD5STEP(long w, long f, long x, long y, long z, long data,
			long s) {
		w = w + f + data & 0xffffffffL;
		w = (w << (int) s | w >> (int) ((long) 32 - s)) & 0xffffffffL;
		w = w + x & 0xffffffffL;
		return w;
	}

	private void MD5Transform() {
		long a = m_buf[0];
		long b = m_buf[1];
		long c = m_buf[2];
		long d = m_buf[3];
		a = MD5STEP(a, F1(b, c, d), b, c, d, bp2long(m_in, 0) + 0xd76aa478L, 7L);
		d = MD5STEP(d, F1(a, b, c), a, b, c, bp2long(m_in, 1) + 0xe8c7b756L,
				12L);
		c = MD5STEP(c, F1(d, a, b), d, a, b, bp2long(m_in, 2) + 0x242070dbL,
				17L);
		b = MD5STEP(b, F1(c, d, a), c, d, a, bp2long(m_in, 3) + 0xc1bdceeeL,
				22L);
		a = MD5STEP(a, F1(b, c, d), b, c, d, bp2long(m_in, 4) + 0xf57c0fafL, 7L);
		d = MD5STEP(d, F1(a, b, c), a, b, c, bp2long(m_in, 5) + 0x4787c62aL,
				12L);
		c = MD5STEP(c, F1(d, a, b), d, a, b, bp2long(m_in, 6) + 0xa8304613L,
				17L);
		b = MD5STEP(b, F1(c, d, a), c, d, a, bp2long(m_in, 7) + 0xfd469501L,
				22L);
		a = MD5STEP(a, F1(b, c, d), b, c, d, bp2long(m_in, 8) + 0x698098d8L, 7L);
		d = MD5STEP(d, F1(a, b, c), a, b, c, bp2long(m_in, 9) + 0x8b44f7afL,
				12L);
		c = MD5STEP(c, F1(d, a, b), d, a, b, bp2long(m_in, 10) + 0xffff5bb1L,
				17L);
		b = MD5STEP(b, F1(c, d, a), c, d, a, bp2long(m_in, 11) + 0x895cd7beL,
				22L);
		a = MD5STEP(a, F1(b, c, d), b, c, d, bp2long(m_in, 12) + 0x6b901122L,
				7L);
		d = MD5STEP(d, F1(a, b, c), a, b, c, bp2long(m_in, 13) + 0xfd987193L,
				12L);
		c = MD5STEP(c, F1(d, a, b), d, a, b, bp2long(m_in, 14) + 0xa679438eL,
				17L);
		b = MD5STEP(b, F1(c, d, a), c, d, a, bp2long(m_in, 15) + 0x49b40821L,
				22L);
		a = MD5STEP(a, F2(b, c, d), b, c, d, bp2long(m_in, 1) + 0xf61e2562L, 5L);
		d = MD5STEP(d, F2(a, b, c), a, b, c, bp2long(m_in, 6) + 0xc040b340L, 9L);
		c = MD5STEP(c, F2(d, a, b), d, a, b, bp2long(m_in, 11) + 0x265e5a51L,
				14L);
		b = MD5STEP(b, F2(c, d, a), c, d, a, bp2long(m_in, 0) + 0xe9b6c7aaL,
				20L);
		a = MD5STEP(a, F2(b, c, d), b, c, d, bp2long(m_in, 5) + 0xd62f105dL, 5L);
		d = MD5STEP(d, F2(a, b, c), a, b, c, bp2long(m_in, 10) + 0x2441453L, 9L);
		c = MD5STEP(c, F2(d, a, b), d, a, b, bp2long(m_in, 15) + 0xd8a1e681L,
				14L);
		b = MD5STEP(b, F2(c, d, a), c, d, a, bp2long(m_in, 4) + 0xe7d3fbc8L,
				20L);
		a = MD5STEP(a, F2(b, c, d), b, c, d, bp2long(m_in, 9) + 0x21e1cde6L, 5L);
		d = MD5STEP(d, F2(a, b, c), a, b, c, bp2long(m_in, 14) + 0xc33707d6L,
				9L);
		c = MD5STEP(c, F2(d, a, b), d, a, b, bp2long(m_in, 3) + 0xf4d50d87L,
				14L);
		b = MD5STEP(b, F2(c, d, a), c, d, a, bp2long(m_in, 8) + 0x455a14edL,
				20L);
		a = MD5STEP(a, F2(b, c, d), b, c, d, bp2long(m_in, 13) + 0xa9e3e905L,
				5L);
		d = MD5STEP(d, F2(a, b, c), a, b, c, bp2long(m_in, 2) + 0xfcefa3f8L, 9L);
		c = MD5STEP(c, F2(d, a, b), d, a, b, bp2long(m_in, 7) + 0x676f02d9L,
				14L);
		b = MD5STEP(b, F2(c, d, a), c, d, a, bp2long(m_in, 12) + 0x8d2a4c8aL,
				20L);
		a = MD5STEP(a, F3(b, c, d), b, c, d, bp2long(m_in, 5) + 0xfffa3942L, 4L);
		d = MD5STEP(d, F3(a, b, c), a, b, c, bp2long(m_in, 8) + 0x8771f681L,
				11L);
		c = MD5STEP(c, F3(d, a, b), d, a, b, bp2long(m_in, 11) + 0x6d9d6122L,
				16L);
		b = MD5STEP(b, F3(c, d, a), c, d, a, bp2long(m_in, 14) + 0xfde5380cL,
				23L);
		a = MD5STEP(a, F3(b, c, d), b, c, d, bp2long(m_in, 1) + 0xa4beea44L, 4L);
		d = MD5STEP(d, F3(a, b, c), a, b, c, bp2long(m_in, 4) + 0x4bdecfa9L,
				11L);
		c = MD5STEP(c, F3(d, a, b), d, a, b, bp2long(m_in, 7) + 0xf6bb4b60L,
				16L);
		b = MD5STEP(b, F3(c, d, a), c, d, a, bp2long(m_in, 10) + 0xbebfbc70L,
				23L);
		a = MD5STEP(a, F3(b, c, d), b, c, d, bp2long(m_in, 13) + 0x289b7ec6L,
				4L);
		d = MD5STEP(d, F3(a, b, c), a, b, c, bp2long(m_in, 0) + 0xeaa127faL,
				11L);
		c = MD5STEP(c, F3(d, a, b), d, a, b, bp2long(m_in, 3) + 0xd4ef3085L,
				16L);
		b = MD5STEP(b, F3(c, d, a), c, d, a, bp2long(m_in, 6) + 0x4881d05L, 23L);
		a = MD5STEP(a, F3(b, c, d), b, c, d, bp2long(m_in, 9) + 0xd9d4d039L, 4L);
		d = MD5STEP(d, F3(a, b, c), a, b, c, bp2long(m_in, 12) + 0xe6db99e5L,
				11L);
		c = MD5STEP(c, F3(d, a, b), d, a, b, bp2long(m_in, 15) + 0x1fa27cf8L,
				16L);
		b = MD5STEP(b, F3(c, d, a), c, d, a, bp2long(m_in, 2) + 0xc4ac5665L,
				23L);
		a = MD5STEP(a, F4(b, c, d), b, c, d, bp2long(m_in, 0) + 0xf4292244L, 6L);
		d = MD5STEP(d, F4(a, b, c), a, b, c, bp2long(m_in, 7) + 0x432aff97L,
				10L);
		c = MD5STEP(c, F4(d, a, b), d, a, b, bp2long(m_in, 14) + 0xab9423a7L,
				15L);
		b = MD5STEP(b, F4(c, d, a), c, d, a, bp2long(m_in, 5) + 0xfc93a039L,
				21L);
		a = MD5STEP(a, F4(b, c, d), b, c, d, bp2long(m_in, 12) + 0x655b59c3L,
				6L);
		d = MD5STEP(d, F4(a, b, c), a, b, c, bp2long(m_in, 3) + 0x8f0ccc92L,
				10L);
		c = MD5STEP(c, F4(d, a, b), d, a, b, bp2long(m_in, 10) + 0xffeff47dL,
				15L);
		b = MD5STEP(b, F4(c, d, a), c, d, a, bp2long(m_in, 1) + 0x85845dd1L,
				21L);
		a = MD5STEP(a, F4(b, c, d), b, c, d, bp2long(m_in, 8) + 0x6fa87e4fL, 6L);
		d = MD5STEP(d, F4(a, b, c), a, b, c, bp2long(m_in, 15) + 0xfe2ce6e0L,
				10L);
		c = MD5STEP(c, F4(d, a, b), d, a, b, bp2long(m_in, 6) + 0xa3014314L,
				15L);
		b = MD5STEP(b, F4(c, d, a), c, d, a, bp2long(m_in, 13) + 0x4e0811a1L,
				21L);
		a = MD5STEP(a, F4(b, c, d), b, c, d, bp2long(m_in, 4) + 0xf7537e82L, 6L);
		d = MD5STEP(d, F4(a, b, c), a, b, c, bp2long(m_in, 11) + 0xbd3af235L,
				10L);
		c = MD5STEP(c, F4(d, a, b), d, a, b, bp2long(m_in, 2) + 0x2ad7d2bbL,
				15L);
		b = MD5STEP(b, F4(c, d, a), c, d, a, bp2long(m_in, 9) + 0xeb86d391L,
				21L);
		m_buf[0] += a;
		m_buf[1] += b;
		m_buf[2] += c;
		m_buf[3] += d;
	}

}

一个MD5加密的具体例子，很简单

package test;

public class TestMD5 {

	public static void main(String[] args) {

		String password="123456";

		//对password完成MD5加密
		String code=MD5.getInstance().toDigest(password);

		System.out.println(code);
	}

}