java实现md5加密

最新推荐文章于 2024-09-11 16:36:24 发布

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#md5加密的java实现 #MD5加密的简单实现

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下面是一个md5加密的工具类，完全不懂。

public class MD5 {
private static MD5 md5 = null;

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 };

private long state[];

private long count[];

private byte buffer[];

public String digestHexStr;

private byte digest[];

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

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

return digestHexStr;
}

private MD5() {
  state = new long[4];
  count = new long[2];
  buffer = new byte[64];
  digest = new byte[16];
  md5Init();
}

private void md5Init() {
  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) {
  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() {
  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) {
  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) {
  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 getMD5Str(String string) {
return getInstance().getMD5ofStr(string);
}

public static void main(String args[]) {
MD5 md5 = new MD5();
System.out.println(md5.getMD5ofStr("stupid"));
}
}

用的时候这么用：

MD5 md5 = MD5.getInstance();
String md5Pw = md5.getMD5Str(passwd);