A-M baby

2013-04-10 21:29:02 -07:00 · 2013-04-10 21:29:02 -07:00 · db842d013d
commit db842d013d
parent 764da6cbbb
19005 changed files with 197040 additions and 7 deletions
--- a/Task/MD5-Implementation/Java/md5-implementation.java
+++ b/Task/MD5-Implementation/Java/md5-implementation.java
@ -0,0 +1,123 @@
+class MD5
+{
+
+  private static final int INIT_A = 0x67452301;
+  private static final int INIT_B = (int)0xEFCDAB89L;
+  private static final int INIT_C = (int)0x98BADCFEL;
+  private static final int INIT_D = 0x10325476;
+
+  private static final int[] SHIFT_AMTS = {
+    7, 12, 17, 22,
+    5,  9, 14, 20,
+    4, 11, 16, 23,
+    6, 10, 15, 21
+  };
+
+  private static final int[] TABLE_T = new int[64];
+  static
+  {
+    for (int i = 0; i < 64; i++)
+      TABLE_T[i] = (int)(long)((1L << 32) * Math.abs(Math.sin(i + 1)));
+  }
+
+  public static byte[] computeMD5(byte[] message)
+  {
+    int messageLenBytes = message.length;
+    int numBlocks = ((messageLenBytes + 8) >>> 6) + 1;
+    int totalLen = numBlocks << 6;
+    byte[] paddingBytes = new byte[totalLen - messageLenBytes];
+    paddingBytes[0] = (byte)0x80;
+
+    long messageLenBits = (long)messageLenBytes << 3;
+    for (int i = 0; i < 8; i++)
+    {
+      paddingBytes[paddingBytes.length - 8 + i] = (byte)messageLenBits;
+      messageLenBits >>>= 8;
+    }
+
+    int a = INIT_A;
+    int b = INIT_B;
+    int c = INIT_C;
+    int d = INIT_D;
+    int[] buffer = new int[16];
+    for (int i = 0; i < numBlocks; i ++)
+    {
+      int index = i << 6;
+      for (int j = 0; j < 64; j++, index++)
+        buffer[j >>> 2] = ((int)((index < messageLenBytes) ? message[index] : paddingBytes[index - messageLenBytes]) << 24) | (buffer[j >>> 2] >>> 8);
+      int originalA = a;
+      int originalB = b;
+      int originalC = c;
+      int originalD = d;
+      for (int j = 0; j < 64; j++)
+      {
+        int div16 = j >>> 4;
+        int f = 0;
+        int bufferIndex = j;
+        switch (div16)
+        {
+          case 0:
+            f = (b & c) | (~b & d);
+            break;
+
+          case 1:
+            f = (b & d) | (c & ~d);
+            bufferIndex = (bufferIndex * 5 + 1) & 0x0F;
+            break;
+
+          case 2:
+            f = b ^ c ^ d;
+            bufferIndex = (bufferIndex * 3 + 5) & 0x0F;
+            break;
+
+          case 3:
+            f = c ^ (b | ~d);
+            bufferIndex = (bufferIndex * 7) & 0x0F;
+            break;
+        }
+        int temp = b + Integer.rotateLeft(a + f + buffer[bufferIndex] + TABLE_T[j], SHIFT_AMTS[(div16 << 2) | (j & 3)]);
+        a = d;
+        d = c;
+        c = b;
+        b = temp;
+      }
+
+      a += originalA;
+      b += originalB;
+      c += originalC;
+      d += originalD;
+    }
+
+    byte[] md5 = new byte[16];
+    int count = 0;
+    for (int i = 0; i < 4; i++)
+    {
+      int n = (i == 0) ? a : ((i == 1) ? b : ((i == 2) ? c : d));
+      for (int j = 0; j < 4; j++)
+      {
+        md5[count++] = (byte)n;
+        n >>>= 8;
+      }
+    }
+    return md5;
+  }
+
+  public static String toHexString(byte[] b)
+  {
+    StringBuilder sb = new StringBuilder();
+    for (int i = 0; i < b.length; i++)
+    {
+      sb.append(String.format("%02X", b[i] & 0xFF));
+    }
+    return sb.toString();
+  }
+
+  public static void main(String[] args)
+  {
+    String[] testStrings = { "", "a", "abc", "message digest", "abcdefghijklmnopqrstuvwxyz", "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789", "12345678901234567890123456789012345678901234567890123456789012345678901234567890" };
+    for (String s : testStrings)
+      System.out.println("0x" + toHexString(computeMD5(s.getBytes())) + " <== \"" + s + "\"");
+    return;
+  }
+
+}