package gnu.crypto.cipher;

// ----------------------------------------------------------------------------
// $Id: Khazad.java,v 1.10 2005/10/06 04:24:14 rsdio Exp $
//
// Copyright (C) 2001, 2002, 2003, Free Software Foundation, Inc.
//
// This file is part of GNU Crypto.
//
// GNU Crypto is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 2, or (at your option)
// any later version.
//
// GNU Crypto is distributed in the hope that it will be useful, but
// WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
// General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; see the file COPYING.  If not, write to the
//
//    Free Software Foundation Inc.,
//    51 Franklin Street, Fifth Floor,
//    Boston, MA 02110-1301
//    USA
//
// Linking this library statically or dynamically with other modules is
// making a combined work based on this library.  Thus, the terms and
// conditions of the GNU General Public License cover the whole
// combination.
//
// As a special exception, the copyright holders of this library give
// you permission to link this library with independent modules to
// produce an executable, regardless of the license terms of these
// independent modules, and to copy and distribute the resulting
// executable under terms of your choice, provided that you also meet,
// for each linked independent module, the terms and conditions of the
// license of that module.  An independent module is a module which is
// not derived from or based on this library.  If you modify this
// library, you may extend this exception to your version of the
// library, but you are not obligated to do so.  If you do not wish to
// do so, delete this exception statement from your version.
// ----------------------------------------------------------------------------

import gnu.crypto.Registry;
import gnu.crypto.util.Util;

//import java.io.PrintWriter;
import java.security.InvalidKeyException;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Iterator;

/**
 * <p>Khazad is a 64-bit (legacy-level) block cipher that accepts a 128-bit key.
 * The cipher is a uniform substitution-permutation network whose inverse only
 * differs from the forward operation in the key schedule. The overall cipher
 * design follows the Wide Trail strategy, favours component reuse, and permits
 * a wide variety of implementation trade-offs.</p>
 *
 * <p>References:</p>
 *
 * <ol>
 *    <li><a href="http://planeta.terra.com.br/informatica/paulobarreto/KhazadPage.html">The
 *    Khazad Block Cipher</a>.<br>
 *    <a href="mailto:paulo.barreto@terra.com.br">Paulo S.L.M. Barreto</a> and
 *    <a href="mailto:vincent.rijmen@esat.kuleuven.ac.be">Vincent Rijmen</a>.</li>
 * </ol>
 *
 * @version $Revision: 1.10 $
 */
public final class Khazad extends BaseCipher {

   // Debugging methods and variables
   // -------------------------------------------------------------------------

//   private static final String NAME = "khazad";
   private static final boolean DEBUG = false;
   private static final int debuglevel = 9;
//   private static final PrintWriter err = new PrintWriter(System.out, true);
//   private static void debug(String s) {
//      err.println(">>> "+NAME+": "+s);
//   }

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

   private static final int DEFAULT_BLOCK_SIZE = 8; // in bytes
   private static final int DEFAULT_KEY_SIZE = 16; // in bytes
   private static final int R = 8; // standard number of rounds; para. 3.7

   private static final String Sd = // p. 20 [KHAZAD]
      "\uBA54\u2F74\u53D3\uD24D\u50AC\u8DBF\u7052\u9A4C"+
      "\uEAD5\u97D1\u3351\u5BA6\uDE48\uA899\uDB32\uB7FC"+
      "\uE39E\u919B\uE2BB\u416E\uA5CB\u6B95\uA1F3\uB102"+
      "\uCCC4\u1D14\uC363\uDA5D\u5FDC\u7DCD\u7F5A\u6C5C"+
      "\uF726\uFFED\uE89D\u6F8E\u19A0\uF089\u0F07\uAFFB"+
      "\u0815\u0D04\u0164\uDF76\u79DD\u3D16\u3F37\u6D38"+
      "\uB973\uE935\u5571\u7B8C\u7288\uF62A\u3E5E\u2746"+
      "\u0C65\u6861\u03C1\u57D6\uD958\uD866\uD73A\uC83C"+
      "\uFA96\uA798\uECB8\uC7AE\u694B\uABA9\u670A\u47F2"+
      "\uB522\uE5EE\uBE2B\u8112\u831B\u0E23\uF545\u21CE"+
      "\u492C\uF9E6\uB628\u1782\u1A8B\uFE8A\u09C9\u874E"+
      "\uE12E\uE4E0\uEB90\uA41E\u8560\u0025\uF4F1\u940B"+
      "\uE775\uEF34\u31D4\uD086\u7EAD\uFD29\u303B\u9FF8"+
      "\uC613\u0605\uC511\u777C\u7A78\u361C\u3959\u1856"+
      "\uB3B0\u2420\uB292\uA3C0\u4462\u10B4\u8443\u93C2"+
      "\u4ABD\u8F2D\uBC9C\u6A40\uCFA2\u804F\u1FCA\uAA42";

   private static final byte[] S = new byte[256];

   private static final int[] T0 = new int[256];
   private static final int[] T1 = new int[256];
   private static final int[] T2 = new int[256];
   private static final int[] T3 = new int[256];
   private static final int[] T4 = new int[256];
   private static final int[] T5 = new int[256];
   private static final int[] T6 = new int[256];
   private static final int[] T7 = new int[256];

   private static final int[][] rc = new int[R + 1][2]; // round constants

   /**
    * KAT vector (from ecb_vk):
    * I=120
    * KEY=00000000000000000000000000000100
    * CT=A0C86A1BBE2CBF4C
    */
   private static final byte[] KAT_KEY =
         Util.toBytesFromString("00000000000000000000000000000100");
   private static final byte[] KAT_CT =
         Util.toBytesFromString("A0C86A1BBE2CBF4C");

   /** caches the result of the correctness test, once executed. */
   private static Boolean valid;

   // Static code - to intialise lookup tables --------------------------------

   static {
      long time = System.currentTimeMillis();

      long ROOT = 0x11d; // para. 2.1 [KHAZAD]
      int i, j;
      int s, s2, s3, s4, s5, s6, s7, s8, sb;
      char c;
      for (i = 0; i < 256; i++) {
         c = Sd.charAt(i >>> 1);
         s = ((i & 1) == 0 ? c >>> 8 : c) & 0xFF;
         S[i] = (byte) s;

         s2 = s << 1;
         if (s2 > 0xFF)
            s2 ^= ROOT;

         s3 = s2 ^ s;
         s4 = s2 << 1;
         if (s4 > 0xFF)
            s4 ^= ROOT;

         s5 = s4 ^ s;
         s6 = s4 ^ s2;
         s7 = s6 ^ s;
         s8 = s4 << 1;
         if (s8 > 0xFF)
            s8 ^= ROOT;

         sb = s8 ^ s2 ^ s;

         T0[i] = s  << 24 | s3 << 16 | s4 << 8 | s5;
         T1[i] = s3 << 24 | s  << 16 | s5 << 8 | s4;
         T2[i] = s4 << 24 | s5 << 16 | s  << 8 | s3;
         T3[i] = s5 << 24 | s4 << 16 | s3 << 8 | s ;
         T4[i] = s6 << 24 | s8 << 16 | sb << 8 | s7;
         T5[i] = s8 << 24 | s6 << 16 | s7 << 8 | sb;
         T6[i] = sb << 24 | s7 << 16 | s6 << 8 | s8;
         T7[i] = s7 << 24 | sb << 16 | s8 << 8 | s6;
      }

      for (i = 0, j = 0; i < R+1; i++) {
         // compute round constant
         rc[i][0] = S[j++]         << 24 |
                   (S[j++] & 0xFF) << 16 |
                   (S[j++] & 0xFF) <<  8 |
                   (S[j++] & 0xFF);
         rc[i][1] = S[j++]         << 24 |
                   (S[j++] & 0xFF) << 16 |
                   (S[j++] & 0xFF) <<  8 |
                   (S[j++] & 0xFF);
      }

      time = System.currentTimeMillis() - time;

      if (DEBUG && debuglevel > 8) {
         System.out.println("==========");
         System.out.println();
         System.out.println("Static data");
         System.out.println();

         System.out.println();
         System.out.println("T0[]:");
         for (i = 0; i < 64; i++) {
            for (j = 0; j < 4; j++)
               System.out.print("0x"+Util.toString(T0[i*4+j])+", ");
            System.out.println();
         }
         System.out.println();
         System.out.println("T1[]:");
         for(i = 0; i < 64; i++) {
            for (j = 0; j < 4; j++)
               System.out.print("0x"+Util.toString(T1[i*4+j])+", ");
            System.out.println();
         }
         System.out.println();
         System.out.println("T2[]:");
         for (i = 0; i < 64; i++) {
            for (j = 0; j < 4; j++)
               System.out.print("0x"+Util.toString(T2[i*4+j])+", ");
            System.out.println();
         }
         System.out.println();
         System.out.println("T3[]:");
         for (i = 0; i < 64; i++) {
            for (j = 0; j < 4; j++)
               System.out.print("0x"+Util.toString(T3[i*4+j])+", ");
            System.out.println();
         }
         System.out.println();
         System.out.println("T4[]:");
         for (i = 0; i < 64; i++) {
            for (j = 0; j < 4; j++)
               System.out.print("0x"+Util.toString(T4[i*4+j])+", ");
            System.out.println();
         }
         System.out.println();
         System.out.println("T5[]:");
         for (i = 0; i < 64; i++) {
            for (j = 0; j < 4; j++)
               System.out.print("0x"+Util.toString(T5[i*4+j])+", ");
            System.out.println();
         }
         System.out.println();
         System.out.println("T6[]:");
         for (i = 0; i < 64; i++) {
            for (j = 0; j < 4; j++)
               System.out.print("0x"+Util.toString(T6[i*4+j])+", ");
            System.out.println();
         }
         System.out.println();
         System.out.println("T7[]:");
         for (i = 0; i < 64; i++) {
            for (j = 0; j < 4; j++)
               System.out.print("0x"+Util.toString(T7[i*4+j])+", ");
            System.out.println();
         }
         System.out.println();
         System.out.println("rc[]:");
         for (i = 0; i < R+1; i++)
            System.out.print("0x"+Util.toString(rc[i][0])+Util.toString(rc[i][1]));
         System.out.println();

         System.out.println("Total initialization time: "+time+" ms.");
         System.out.println();
      }
   }

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

   /** Trivial 0-arguments constructor. */
   public Khazad() {
      super(Registry.KHAZAD_CIPHER, DEFAULT_BLOCK_SIZE, DEFAULT_KEY_SIZE);
   }

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

   private static void khazad(byte[] in, int i, byte[] out, int j, int[][] K) {
      // sigma(K[0])
      int k0 = K[0][0];
      int k1 = K[0][1];
      int a0 = ( in[i++]         << 24 |
                (in[i++] & 0xFF) << 16 |
                (in[i++] & 0xFF) <<  8 |
                (in[i++] & 0xFF)        ) ^ k0;
      int a1 = ( in[i++]         << 24 |
                (in[i++] & 0xFF) << 16 |
                (in[i++] & 0xFF) <<  8 |
                (in[i  ] & 0xFF)        ) ^ k1;

      int b0, b1;
      // round function
      for (int r = 1; r < R; r++) {
         k0 = K[r][0];
         k1 = K[r][1];
         b0 = T0[ a0 >>> 24        ] ^
              T1[(a0 >>> 16) & 0xFF] ^
              T2[(a0 >>>  8) & 0xFF] ^
              T3[ a0         & 0xFF] ^
              T4[ a1 >>> 24        ] ^
              T5[(a1 >>> 16) & 0xFF] ^
              T6[(a1 >>>  8) & 0xFF] ^
              T7[ a1         & 0xFF] ^ k0;
         b1 = T0[ a1 >>> 24        ] ^
              T1[(a1 >>> 16) & 0xFF] ^
              T2[(a1 >>>  8) & 0xFF] ^
              T3[ a1         & 0xFF] ^
              T4[ a0 >>> 24        ] ^
              T5[(a0 >>> 16) & 0xFF] ^
              T6[(a0 >>>  8) & 0xFF] ^
              T7[ a0         & 0xFF] ^ k1;
         a0 = b0;
         a1 = b1;

         if (DEBUG && debuglevel > 6) {
            System.out.println("T"+r+"="+Util.toString(a0)+Util.toString(a1));
         }
      }

      // sigma(K[R]) o gamma applied to previous output
      k0 = K[R][0];
      k1 = K[R][1];

      out[j++] = (byte)(S[ a0 >>> 24        ] ^ (k0 >>> 24));
      out[j++] = (byte)(S[(a0 >>> 16) & 0xFF] ^ (k0 >>> 16));
      out[j++] = (byte)(S[(a0 >>>  8) & 0xFF] ^ (k0 >>>  8));
      out[j++] = (byte)(S[ a0         & 0xFF] ^  k0        );
      out[j++] = (byte)(S[ a1 >>> 24        ] ^ (k1 >>> 24));
      out[j++] = (byte)(S[(a1 >>> 16) & 0xFF] ^ (k1 >>> 16));
      out[j++] = (byte)(S[(a1 >>>  8) & 0xFF] ^ (k1 >>>  8));
      out[j  ] = (byte)(S[ a1         & 0xFF] ^  k1        );

      if (DEBUG && debuglevel > 6) {
         System.out.println("T="+Util.toString(out, j-7, 8));
         System.out.println();
      }
   }

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

   // java.lang.Cloneable interface implementation ----------------------------

   public Object clone() {
      Khazad result = new Khazad();
      result.currentBlockSize = this.currentBlockSize;

      return result;
   }

   // IBlockCipherSpi interface implementation --------------------------------

   public Iterator blockSizes() {
      ArrayList al = new ArrayList();
      al.add(new Integer(DEFAULT_BLOCK_SIZE));

      return Collections.unmodifiableList(al).iterator();
   }

   public Iterator keySizes() {
      ArrayList al = new ArrayList();
      al.add(new Integer(DEFAULT_KEY_SIZE));

      return Collections.unmodifiableList(al).iterator();
   }

   /**
    * <p>Expands a user-supplied key material into a session key for a
    * designated <i>block size</i>.</p>
    *
    * @param uk the 128-bit user-supplied key material.
    * @param bs the desired block size in bytes.
    * @return an Object encapsulating the session key.
    * @exception IllegalArgumentException if the block size is not 16 (128-bit).
    * @exception InvalidKeyException if the key data is invalid.
    */
   public Object makeKey(byte[] uk, int bs) throws InvalidKeyException {
      if (bs != DEFAULT_BLOCK_SIZE) {
         throw new IllegalArgumentException();
      }
      if (uk == null) {
         throw new InvalidKeyException("Empty key");
      }
      if (uk.length != 16) {
         throw new InvalidKeyException("Key is not 128-bit.");
      }
      int[][] Ke = new int[R + 1][2]; // encryption round keys
      int[][] Kd = new int[R + 1][2]; // decryption round keys

      int r, i;
      int k20, k21, k10, k11, rc0, rc1, kr0, kr1;

      i = 0;
      k20 = uk[i++]         << 24 |
           (uk[i++] & 0xFF) << 16 |
           (uk[i++] & 0xFF) <<  8 |
           (uk[i++] & 0xFF);
      k21 = uk[i++]         << 24 |
           (uk[i++] & 0xFF) << 16 |
           (uk[i++] & 0xFF) <<  8 |
           (uk[i++] & 0xFF);
      k10 = uk[i++]         << 24 |
           (uk[i++] & 0xFF) << 16 |
           (uk[i++] & 0xFF) <<  8 |
           (uk[i++] & 0xFF);
      k11 = uk[i++]         << 24 |
           (uk[i++] & 0xFF) << 16 |
           (uk[i++] & 0xFF) <<  8 |
           (uk[i++] & 0xFF);

      for (r = 0, i = 0; r <= R; r++) {
         rc0 = rc[r][0];
         rc1 = rc[r][1];

         kr0 = T0[ k10 >>> 24        ] ^
               T1[(k10 >>> 16) & 0xFF] ^
               T2[(k10 >>>  8) & 0xFF] ^
               T3[ k10         & 0xFF] ^
               T4[(k11 >>> 24) & 0xFF] ^
               T5[(k11 >>> 16) & 0xFF] ^
               T6[(k11 >>>  8) & 0xFF] ^
               T7[ k11         & 0xFF] ^ rc0 ^ k20;
         kr1 = T0[ k11 >>> 24        ] ^
               T1[(k11 >>> 16) & 0xFF] ^
               T2[(k11 >>>  8) & 0xFF] ^
               T3[ k11         & 0xFF] ^
               T4[(k10 >>> 24) & 0xFF] ^
               T5[(k10 >>> 16) & 0xFF] ^
               T6[(k10 >>>  8) & 0xFF] ^
               T7[ k10         & 0xFF] ^ rc1 ^ k21;

         Ke[r][0] = kr0;
         Ke[r][1] = kr1;
         k20 = k10;
         k21 = k11;
         k10 = kr0;
         k11 = kr1;

         if (r == 0 || r == R) {
            Kd[R-r][0] = kr0;
            Kd[R-r][1] = kr1;
         } else {
            Kd[R-r][0] = T0[S[ kr0 >>> 24        ] & 0xFF] ^
                         T1[S[(kr0 >>> 16) & 0xFF] & 0xFF] ^
                         T2[S[(kr0 >>>  8) & 0xFF] & 0xFF] ^
                         T3[S[ kr0         & 0xFF] & 0xFF] ^
                         T4[S[ kr1 >>> 24        ] & 0xFF] ^
                         T5[S[(kr1 >>> 16) & 0xFF] & 0xFF] ^
                         T6[S[(kr1 >>>  8) & 0xFF] & 0xFF] ^
                         T7[S[ kr1         & 0xFF] & 0xFF];
            Kd[R-r][1] = T0[S[ kr1 >>> 24        ] & 0xFF] ^
                         T1[S[(kr1 >>> 16) & 0xFF] & 0xFF] ^
                         T2[S[(kr1 >>>  8) & 0xFF] & 0xFF] ^
                         T3[S[ kr1         & 0xFF] & 0xFF] ^
                         T4[S[ kr0 >>> 24        ] & 0xFF] ^
                         T5[S[(kr0 >>> 16) & 0xFF] & 0xFF] ^
                         T6[S[(kr0 >>>  8) & 0xFF] & 0xFF] ^
                         T7[S[ kr0         & 0xFF] & 0xFF];
         }
      }

      if (DEBUG && debuglevel > 8) {
         System.out.println();
         System.out.println("Key schedule");
         System.out.println();
         System.out.println("Ke[]:");
         for (r = 0; r < R+1; r++) {
            System.out.println("#"+r+": 0x"
               +Util.toString(Ke[r][0])+Util.toString(Ke[r][1]));
         }
         System.out.println();
         System.out.println("Kd[]:");
         for (r = 0; r < R+1; r++) {
            System.out.println("#"+r+": 0x"
               +Util.toString(Kd[r][0])+Util.toString(Kd[r][1]));
         }
         System.out.println();
      }

      return new Object[] {Ke, Kd};
   }

   public void encrypt(byte[] in, int i, byte[] out, int j, Object k, int bs) {
      if (bs != DEFAULT_BLOCK_SIZE) {
         throw new IllegalArgumentException();
      }

      int[][] K = (int[][])((Object[]) k)[0];
      khazad(in, i, out, j, K);
   }

   public void decrypt(byte[] in, int i, byte[] out, int j, Object k, int bs) {
      if (bs != DEFAULT_BLOCK_SIZE) {
         throw new IllegalArgumentException();
      }

      int[][] K = (int[][])((Object[]) k)[1];
      khazad(in, i, out, j, K);
   }

   public boolean selfTest() {
      if (valid == null) {
         boolean result = super.selfTest(); // do symmetry tests
         if (result) {
            result = testKat(KAT_KEY, KAT_CT);
         }
         valid = new Boolean(result);
      }
      return valid.booleanValue();
   }
}
