des4.java

DES加密和解密算法

      int w = 0x88888888;
      int n = PARITY[kb[offset+0] & 0xff]; n <<= 4;
      n |= PARITY[kb[offset+1] & 0xff]; n <<= 4;
      n |= PARITY[kb[offset+2] & 0xff]; n <<= 4;
      n |= PARITY[kb[offset+3] & 0xff]; n <<= 4;
      n |= PARITY[kb[offset+4] & 0xff]; n <<= 4;
      n |= PARITY[kb[offset+5] & 0xff]; n <<= 4;
      n |= PARITY[kb[offset+6] & 0xff]; n <<= 4;
      n |= PARITY[kb[offset+7] & 0xff];
      return (n & w) == 0;
   }

   /**
    * <p>Test if a key is a weak key.</p>
    *
    * @param kb The key to test.
    * @return <code>true</code> if the key is weak.
    */
   public static boolean isWeak(byte[] kb) {
//      return Arrays.equals(kb, WEAK_KEYS[0]) || Arrays.equals(kb, WEAK_KEYS[1])
//          || Arrays.equals(kb, WEAK_KEYS[2]) || Arrays.equals(kb, WEAK_KEYS[3])
//          || Arrays.equals(kb, WEAK_KEYS[4]) || Arrays.equals(kb, WEAK_KEYS[5])
//          || Arrays.equals(kb, WEAK_KEYS[6]) || Arrays.equals(kb, WEAK_KEYS[7]);
      for (int i = 0; i < WEAK_KEYS.length; i++) {
         if (Arrays.equals(WEAK_KEYS[i], kb)) {
            return true;
         }
      }
      return false;
   }

   /**
    * <p>Test if a key is a semi-weak key.</p>
    *
    * @param kb The key to test.
    * @return <code>true</code> if this key is semi-weak.
    */
   public static boolean isSemiWeak(byte[] kb) {
//      return Arrays.equals(kb, SEMIWEAK_KEYS[0])
//          || Arrays.equals(kb, SEMIWEAK_KEYS[1])
//          || Arrays.equals(kb, SEMIWEAK_KEYS[2])
//          || Arrays.equals(kb, SEMIWEAK_KEYS[3])
//          || Arrays.equals(kb, SEMIWEAK_KEYS[4])
//          || Arrays.equals(kb, SEMIWEAK_KEYS[5])
//          || Arrays.equals(kb, SEMIWEAK_KEYS[6])
//          || Arrays.equals(kb, SEMIWEAK_KEYS[7])
//          || Arrays.equals(kb, SEMIWEAK_KEYS[8])
//          || Arrays.equals(kb, SEMIWEAK_KEYS[9])
//          || Arrays.equals(kb, SEMIWEAK_KEYS[10])
//          || Arrays.equals(kb, SEMIWEAK_KEYS[11]);
      for (int i = 0; i < SEMIWEAK_KEYS.length; i++) {
         if (Arrays.equals(SEMIWEAK_KEYS[i], kb)) {
            return true;
         }
      }
      return false;
   }

   /**
    * <p>Test if the designated byte array represents a possibly weak key.</p>
    *
    * @param kb the byte array to test.
    * @return <code>true</code> if <code>kb</code>represents a possibly weak key.
    * Returns <code>false</code> otherwise.
    */
   public static boolean isPossibleWeak(byte[] kb) {
      for (int i = 0; i < POSSIBLE_WEAK_KEYS.length; i++) {
         if (Arrays.equals(POSSIBLE_WEAK_KEYS[i], kb)) {
            return true;
         }
      }
      return false;
   }

   /**
    * <p>The core DES function. This is used for both encryption and decryption,
    * the only difference being the key.</p>
    *
    * @param in The input bytes.
    * @param i The starting offset into the input bytes.
    * @param out The output bytes.
    * @param o The starting offset into the output bytes.
    * @param key The working key.
    */
   private static void desFunc(byte[] in, int i, byte[] out, int o, int[] key) {
      int right, left, work;

      // Load.
      left  = (in[i++] & 0xff) << 24 | (in[i++] & 0xff) << 16
            | (in[i++] & 0xff) <<  8 |  in[i++] & 0xff;
      right = (in[i++] & 0xff) << 24 | (in[i++] & 0xff) << 16
            | (in[i++] & 0xff) <<  8 |  in[i  ] & 0xff;

      // Initial permutation.
      work  = ((left >>>  4) ^ right) & 0x0F0F0F0F;
      left  ^= work << 4;
      right ^= work;

      work  = ((left >>> 16) ^ right) & 0x0000FFFF;
      left  ^= work << 16;
      right ^= work;

      work  = ((right >>>  2) ^ left) & 0x33333333;
      right ^= work << 2;
      left  ^= work;

      work  = ((right >>>  8) ^ left) & 0x00FF00FF;
      right ^= work << 8;
      left  ^= work;

      right = ((right << 1) | ((right >>> 31) & 1)) & 0xFFFFFFFF;
      work = (left ^ right) & 0xAAAAAAAA;
      left  ^= work;
      right ^= work;
      left = ((left << 1) | ((left >>> 31) & 1)) & 0xFFFFFFFF;

      int k = 0, t;
      for (int round = 0; round < 8; round++) {
         work = right >>> 4 | right << 28;
         work ^= key[k++];
         t  = SP7[work & 0x3F]; work >>>= 8;
         t |= SP5[work & 0x3F]; work >>>= 8;
         t |= SP3[work & 0x3F]; work >>>= 8;
         t |= SP1[work & 0x3F];
         work = right ^ key[k++];
         t |= SP8[work & 0x3F]; work >>>= 8;
         t |= SP6[work & 0x3F]; work >>>= 8;
         t |= SP4[work & 0x3F]; work >>>= 8;
         t |= SP2[work & 0x3F];
         left ^= t;

         work = left >>> 4 | left << 28;
         work ^= key[k++];
         t  = SP7[work & 0x3F]; work >>>= 8;
         t |= SP5[work & 0x3F]; work >>>= 8;
         t |= SP3[work & 0x3F]; work >>>= 8;
         t |= SP1[work & 0x3F];
         work = left ^ key[k++];
         t |= SP8[work & 0x3F]; work >>>= 8;
         t |= SP6[work & 0x3F]; work >>>= 8;
         t |= SP4[work & 0x3F]; work >>>= 8;
         t |= SP2[work & 0x3F];
         right ^= t;
      }

      // The final permutation.
      right = (right << 31) | (right >>> 1);
      work = (left ^ right) & 0xAAAAAAAA;
      left  ^= work;
      right ^= work;
      left = (left << 31) | (left >>> 1);

      work = ((left >>> 8) ^ right) & 0x00FF00FF;
      left ^= work << 8;
      right ^= work;

      work = ((left >>> 2) ^ right) & 0x33333333;
      left  ^= work << 2;
      right ^= work;

      work = ((right >>> 16) ^ left) & 0x0000FFFF;
      right ^= work << 16;
      left  ^= work;

      work = ((right >>> 4) ^ left) & 0x0F0F0F0F;
      right ^= work << 4;
      left  ^= work;

      out[o++] = (byte)(right >>> 24);
      out[o++] = (byte)(right >>> 16);
      out[o++] = (byte)(right >>>  8);
      out[o++] = (byte) right;
      out[o++] = (byte)(left >>> 24);
      out[o++] = (byte)(left >>> 16);
      out[o++] = (byte)(left >>>  8);
      out[o  ] = (byte) left;
   }

   // Instance methods implementing BaseCipher
   // -------------------------------------------------------------------------

   public Object clone() {
      return new DES();
   }

   public Iterator blockSizes() {
      return Collections.singleton(new Integer(BLOCK_SIZE)).iterator();
   }

   public Iterator keySizes() {
      return Collections.singleton(new Integer(KEY_SIZE)).iterator();
   }

   public Object makeKey(byte[] kb, int bs) throws InvalidKeyException {
      if (kb == null || kb.length != KEY_SIZE)
         throw new InvalidKeyException("DES keys must be 8 bytes long");

      if (Properties.checkForWeakKeys()
            && (isWeak(kb) || isSemiWeak(kb) || isPossibleWeak(kb))) {
         throw new WeakKeyException();
      }

      int i, j, l, m, n;
      long pc1m = 0, pcr = 0;

      for (i = 0; i < 56; i++) {
         l = PC1[i];
         pc1m |= ((kb[l >>> 3] & (0x80 >>> (l & 7))) != 0)
               ? (1L << (55 - i)) : 0;
      }

      Context ctx = new Context();

      // Encryption key first.
      for (i = 0; i < 16; i++) {
         pcr = 0;
         m = i << 1;
         n = m + 1;
         for (j = 0; j < 28; j++) {
            l = j + ROTARS[i];
            if (l < 28) pcr |= ((pc1m & 1L << (55 - l)) != 0)
                             ? (1L << (55 - j)) : 0;
            else pcr |= ((pc1m & 1L << (55 - (l - 28))) != 0)
                      ? (1L << (55 - j)) : 0;
         }
         for (j = 28; j < 56; j++) {
            l = j + ROTARS[i];
            if (l < 56) pcr |= ((pc1m & 1L << (55 - l)) != 0)
                             ? (1L << (55 - j)) : 0;
            else pcr |= ((pc1m & 1L << (55 - (l - 28))) != 0)
                      ? (1L << (55 - j)) : 0;
         }
         for (j = 0; j < 24; j++) {
            if ((pcr & 1L << (55 - PC2[j   ])) != 0) ctx.ek[m] |= 1 << (23 - j);
            if ((pcr & 1L << (55 - PC2[j+24])) != 0) ctx.ek[n] |= 1 << (23 - j);
         }
      }

      // The decryption key is the same, but in reversed order.
      for (i = 0; i < Context.EXPANDED_KEY_SIZE; i += 2) {
         ctx.dk[30 - i] = ctx.ek[i];
         ctx.dk[31 - i] = ctx.ek[i+1];
      }

      // "Cook" the keys.
      for (i = 0; i < 32; i += 2) {
         int x, y;

         x = ctx.ek[i  ];
         y = ctx.ek[i+1];

         ctx.ek[i  ] = ((x & 0x00FC0000)  <<  6) | ((x & 0x00000FC0)  << 10)
                     | ((y & 0x00FC0000) >>> 10) | ((y & 0x00000FC0) >>>  6);
         ctx.ek[i+1] = ((x & 0x0003F000)  << 12) | ((x & 0x0000003F)  << 16)
                     | ((y & 0x0003F000) >>>  4) |  (y & 0x0000003F);

         x = ctx.dk[i  ];
         y = ctx.dk[i+1];

         ctx.dk[i  ] = ((x & 0x00FC0000)  <<  6) | ((x & 0x00000FC0)  << 10)
                     | ((y & 0x00FC0000) >>> 10) | ((y & 0x00000FC0) >>>  6);
         ctx.dk[i+1] = ((x & 0x0003F000)  << 12) | ((x & 0x0000003F)  << 16)
                     | ((y & 0x0003F000) >>>  4) |  (y & 0x0000003F);
      }

      return ctx;
   }

   public void encrypt(byte[] in, int i, byte[] out, int o, Object K, int bs) {
      desFunc(in, i, out, o, ((Context) K).ek);
   }

   public void decrypt(byte[] in, int i, byte[] out, int o, Object K, int bs) {
      desFunc(in, i, out, o, ((Context) K).dk);
   }
   /**
    * 
    * 将 DES 加密过的 byte数组转换为字符串
    * 
   * @param dataByte
   * @return
   */
  public String byteToString(byte[] dataByte)
   {      
    String returnStr = null;
       BASE64Encoder be = new BASE64Encoder();
       returnStr = be.encode(dataByte);
       return returnStr;      
   }
  /**
   * 输出 byte数组
   * 
  * @param data
  */
 public void printByte(byte[] data)
  {
  System.out.println("*********开始输出字节流**********"); 
  System.out.println("字节流: "+data.toString());
   for(int i = 0 ; i < data.length ; i++){
    System.out.println("第 "+i+"字节为："+ data[i]);
   }
   System.out.println("*********结束输出字节流**********");
  }
   public static void main(String args[]){
	   String str="this is a test";
	   DES4 d=new DES4();
	   byte[] in=str.getBytes();
	   String p=new String(in);
	   System.out.println("加密前的数据"+d.byteToString(in)+p);
	   byte[] out=new byte[in.length];
	   Object k = null;
	try {
		k = d.makeKey("12312345".getBytes(), 12345678);
	} catch (InvalidKeyException e) {
		
		e.printStackTrace();
	}
	   d.encrypt(in,0,out,0,k,12345678);	
	   d.printByte(out);
	   String oo=new String(out);
	   System.out.println("加密后的字符"+oo);
	   System.out.println("加密后的数据"+d.byteToString(out));
	   for(int i=0;i<out.length;i++){
		   System.out.println(oo.getBytes()[i]);
	   }
	   byte in1[]=new byte[out.length]; 
	   d.decrypt(out,0,in1,0,k,12345678);	
	   System.out.println("解密后的数据"+d.byteToString(in1));
	   String tt=new String(in1);
	   System.out.println("解密后的数据"+tt);   
	   
   }
   // Inner classe(s)
   // =========================================================================

   /**
    * Simple wrapper class around the session keys. Package-private so TripleDES
    * can see it.
    */
   final class Context {

      // Constants and variables
      // ----------------------------------------------------------------------

      private static final int EXPANDED_KEY_SIZE = 32;

      /** The encryption key. */
      int[] ek;

      /** The decryption key. */
      int[] dk;

      // Constructor(s)
      // ----------------------------------------------------------------------

      /** Default 0-arguments constructor. */
      Context() {
         ek = new int[EXPANDED_KEY_SIZE];
         dk = new int[EXPANDED_KEY_SIZE];
      }

      // Class methods
      // ----------------------------------------------------------------------

      // Instance methods
      // ----------------------------------------------------------------------

      byte[] getEncryptionKeyBytes() {
         return toByteArray(ek);
      }

      byte[] getDecryptionKeyBytes() {
         return toByteArray(dk);
      }

      byte[] toByteArray(int[] k) {
         byte[] result = new byte[4 * k.length];
         for (int i = 0, j = 0; i < k.length; i++) {
            result[j++] = (byte)(k[i] >>> 24);
            result[j++] = (byte)(k[i] >>> 16);
            result[j++] = (byte)(k[i] >>>  8);
            result[j++] = (byte) k[i];
         }
         return result;
      }
   }
}