rijndael_algorithm.java

Its about cryptography example. useful for chatting with some sort of security

// $Id: $
//
// $Log: $
// Revision 1.1  1998/04/12  Paulo
// + optimized methods for the default 128-bit block size.
//
// Revision 1.0  1998/03/11  Raif
// + original version.
//
// $Endlog$
/*
 * Copyright (c) 1997, 1998 Systemics Ltd on behalf of
 * the Cryptix Development Team. All rights reserved.
 */
package rijndael;

import java.io.PrintWriter;
import java.security.InvalidKeyException;

//...........................................................................
/**
 * Rijndael --pronounced Reindaal-- is a variable block-size (128-, 192- and
 * 256-bit), variable key-size (128-, 192- and 256-bit) symmetric cipher.<p>
 *
 * Rijndael was written by <a href="mailto:[e-mail]">Vincent
 * Rijmen</a> and <a href="mailto:[e-mail]">Joan Daemen</a>.<p>
 *
 * Portions of this code are <b>Copyright</b> &copy; 1997, 1998
 * <a href="http://www.systemics.com/">Systemics Ltd</a> on behalf of the
 * <a href="http://www.systemics.com/docs/cryptix/">Cryptix Development Team</a>.
 * <br>All rights reserved.<p>
 *
 * <b>$Revision: $</b>
 * @author  Raif S. Naffah
 * @author  Paulo S. L. M. Barreto
 */
public final class Rijndael_Algorithm // implicit no-argument constructor
{
// Debugging methods and variables
//...........................................................................

    static final String NAME = "Rijndael_Algorithm";
    static final boolean IN = true, OUT = false;

    static final boolean DEBUG = Rijndael_Properties.GLOBAL_DEBUG;
    static final int debuglevel = DEBUG ? Rijndael_Properties.getLevel(NAME) : 0;
    static final PrintWriter err = DEBUG ? Rijndael_Properties.getOutput() : null;

    static final boolean TRACE = Rijndael_Properties.isTraceable(NAME);

    static void debug (String s) { err.println(">>> "+NAME+": "+s); }
    static void trace (boolean in, String s) {
        if (TRACE) err.println((in?"==> ":"<== ")+NAME+"."+s);
    }
    static void trace (String s) { if (TRACE) err.println("<=> "+NAME+"."+s); }


// Constants and variables
//...........................................................................

    static final int BLOCK_SIZE = 16; // default block size in bytes

    static final int[] alog = new int[256];
    static final int[] log =  new int[256];

    static final byte[] S =  new byte[256];
    static final byte[] Si = new byte[256];
    static final int[] T1 = new int[256];
    static final int[] T2 = new int[256];
    static final int[] T3 = new int[256];
    static final int[] T4 = new int[256];
    static final int[] T5 = new int[256];
    static final int[] T6 = new int[256];
    static final int[] T7 = new int[256];
    static final int[] T8 = new int[256];
    static final int[] U1 = new int[256];
    static final int[] U2 = new int[256];
    static final int[] U3 = new int[256];
    static final int[] U4 = new int[256];
    static final byte[] rcon = new byte[30];

    static final int[][][] shifts = new int[][][] {
        { {0, 0}, {1, 3}, {2, 2}, {3, 1} },
        { {0, 0}, {1, 5}, {2, 4}, {3, 3} },
        { {0, 0}, {1, 7}, {3, 5}, {4, 4} }
    };

    private static final char[] HEX_DIGITS = {
        '0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F'
    };


// Static code - to intialise S-boxes and T-boxes
//...........................................................................

    static {
        long time = System.currentTimeMillis();

if (DEBUG && debuglevel > 6) {
System.out.println("Algorithm Name: "+Rijndael_Properties.FULL_NAME);
System.out.println("Electronic Codebook (ECB) Mode");
System.out.println();
}
        int ROOT = 0x11B;
        int i, j = 0;

        //
        // produce log and alog tables, needed for multiplying in the
        // field GF(2^m) (generator = 3)
        //
        alog[0] = 1;
        for (i = 1; i < 256; i++) {
            j = (alog[i-1] << 1) ^ alog[i-1];
            if ((j & 0x100) != 0) j ^= ROOT;
            alog[i] = j;
        }
        for (i = 1; i < 255; i++) log[alog[i]] = i;
        byte[][] A = new byte[][] {
            {1, 1, 1, 1, 1, 0, 0, 0},
            {0, 1, 1, 1, 1, 1, 0, 0},
		    {0, 0, 1, 1, 1, 1, 1, 0},
		    {0, 0, 0, 1, 1, 1, 1, 1},
		    {1, 0, 0, 0, 1, 1, 1, 1},
		    {1, 1, 0, 0, 0, 1, 1, 1},
		    {1, 1, 1, 0, 0, 0, 1, 1},
		    {1, 1, 1, 1, 0, 0, 0, 1}
		};
        byte[] B = new byte[] { 0, 1, 1, 0, 0, 0, 1, 1};

        //
        // substitution box based on F^{-1}(x)
        //
        int t;
        byte[][] box = new byte[256][8];
        box[1][7] = 1;
        for (i = 2; i < 256; i++) {
            j = alog[255 - log[i]];
            for (t = 0; t < 8; t++)
                box[i][t] = (byte)((j >>> (7 - t)) & 0x01);
        }
        //
        // affine transform:  box[i] <- B + A*box[i]
        //
        byte[][] cox = new byte[256][8];
        for (i = 0; i < 256; i++)
            for (t = 0; t < 8; t++) {
                cox[i][t] = B[t];
                for (j = 0; j < 8; j++)
                    cox[i][t] ^= A[t][j] * box[i][j];
            }
        //
        // S-boxes and inverse S-boxes
        //
        for (i = 0; i < 256; i++) {
            S[i] = (byte)(cox[i][0] << 7);
	        for (t = 1; t < 8; t++)
	            S[i] ^= cox[i][t] << (7-t);
            Si[S[i] & 0xFF] = (byte) i;
        }
        //
        // T-boxes
        //
        byte[][] G = new byte[][] {
            {2, 1, 1, 3},
            {3, 2, 1, 1},
            {1, 3, 2, 1},
            {1, 1, 3, 2}
        };
        byte[][] AA = new byte[4][8];
        for (i = 0; i < 4; i++) {
            for (j = 0; j < 4; j++) AA[i][j] = G[i][j];
            AA[i][i+4] = 1;
        }
        byte pivot, tmp;
        byte[][] iG = new byte[4][4];
        for (i = 0; i < 4; i++) {
            pivot = AA[i][i];
            if (pivot == 0) {
                t = i + 1;
                while ((AA[t][i] == 0) && (t < 4))
                    t++;
                if (t == 4)
                    throw new RuntimeException("G matrix is not invertible");
                else {
                    for (j = 0; j < 8; j++) {
                        tmp = AA[i][j];
                        AA[i][j] = AA[t][j];
                        AA[t][j] = (byte) tmp;
                    }
                    pivot = AA[i][i];
                }
            }
            for (j = 0; j < 8; j++)
                if (AA[i][j] != 0)
                    AA[i][j] = (byte)
                        alog[(255 + log[AA[i][j] & 0xFF] - log[pivot & 0xFF]) % 255];
            for (t = 0; t < 4; t++)
                if (i != t) {
                    for (j = i+1; j < 8; j++)
                        AA[t][j] ^= mul(AA[i][j], AA[t][i]);
                    AA[t][i] = 0;
                }
        }
        for (i = 0; i < 4; i++)
            for (j = 0; j < 4; j++) iG[i][j] = AA[i][j + 4];

        int s;
        for (t = 0; t < 256; t++) {
            s = S[t];
            T1[t] = mul4(s, G[0]);
            T2[t] = mul4(s, G[1]);
            T3[t] = mul4(s, G[2]);
            T4[t] = mul4(s, G[3]);

            s = Si[t];
            T5[t] = mul4(s, iG[0]);
            T6[t] = mul4(s, iG[1]);
            T7[t] = mul4(s, iG[2]);
            T8[t] = mul4(s, iG[3]);

            U1[t] = mul4(t, iG[0]);
            U2[t] = mul4(t, iG[1]);
            U3[t] = mul4(t, iG[2]);
            U4[t] = mul4(t, iG[3]);
        }
        //
        // round constants
        //
        rcon[0] = 1;
        int r = 1;
        for (t = 1; t < 30; ) rcon[t++] = (byte)(r = mul(2, r));

        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("S[]:"); for(i=0;i<16;i++) { for(j=0;j<16;j++) System.out.print("0x"+byteToString(S[i*16+j])+", "); System.out.println();}
System.out.println();
System.out.println("Si[]:"); for(i=0;i<16;i++) { for(j=0;j<16;j++) System.out.print("0x"+byteToString(Si[i*16+j])+", "); System.out.println();}

System.out.println();
System.out.println("iG[]:"); for(i=0;i<4;i++){for(j=0;j<4;j++) System.out.print("0x"+byteToString(iG[i][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"+intToString(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"+intToString(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"+intToString(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"+intToString(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"+intToString(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"+intToString(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"+intToString(T7[i*4+j])+", "); System.out.println();}
System.out.println();
System.out.println("T8[]:"); for(i=0;i<64;i++){for(j=0;j<4;j++) System.out.print("0x"+intToString(T8[i*4+j])+", "); System.out.println();}

System.out.println();
System.out.println("U1[]:"); for(i=0;i<64;i++){for(j=0;j<4;j++) System.out.print("0x"+intToString(U1[i*4+j])+", "); System.out.println();}
System.out.println();
System.out.println("U2[]:"); for(i=0;i<64;i++){for(j=0;j<4;j++) System.out.print("0x"+intToString(U2[i*4+j])+", "); System.out.println();}
System.out.println();
System.out.println("U3[]:"); for(i=0;i<64;i++){for(j=0;j<4;j++) System.out.print("0x"+intToString(U3[i*4+j])+", "); System.out.println();}
System.out.println();
System.out.println("U4[]:"); for(i=0;i<64;i++){for(j=0;j<4;j++) System.out.print("0x"+intToString(U4[i*4+j])+", "); System.out.println();}

System.out.println();
System.out.println("rcon[]:"); for(i=0;i<5;i++){for(j=0;j<6;j++) System.out.print("0x"+byteToString(rcon[i*6+j])+", "); System.out.println();}

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

    // multiply two elements of GF(2^m)
    static final int mul (int a, int b) {
        return (a != 0 && b != 0) ?
            alog[(log[a & 0xFF] + log[b & 0xFF]) % 255] :
            0;
    }