/*

 * Copyright (c) 2000, 2003, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code 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

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

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 *

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/*      Copyright (c) 1988 AT&T */

/*        All Rights Reserved   */

/**

 * Implements the UNIX crypt(3) function, based on a direct port of the

 * libc crypt function.

 *

 * <p>

 * From the crypt man page:

 * <p>

 * crypt() is the password encryption routine, based on the NBS

 * Data  Encryption  Standard,  with variations intended (among

 * other things) to frustrate use of  hardware  implementations

 * of the DES for key search.

 * <p>

 * The first argument to crypt() is  normally  a  user's  typed

 * password.   The  second  is a 2-character string chosen from

 * the set [a-zA-Z0-9./].  the  salt string is used to perturb

 * the DES algorithm in one

 * of 4096 different ways, after which the password is used  as

 * the  key  to  encrypt  repeatedly  a  constant  string.  The

 * returned value points to the encrypted password, in the same

 * alphabet as the salt.  The first two characters are the salt

 * itself.

 *

 * @author Roland Schemers

 */

package com.sun.security.auth.module;

class Crypt {

/* EXPORT DELETE START */

    private static final byte[] IP = {

        58, 50, 42, 34, 26, 18, 10, 2,

        60, 52, 44, 36, 28, 20, 12, 4,

        62, 54, 46, 38, 30, 22, 14, 6,

        64, 56, 48, 40, 32, 24, 16, 8,

        57, 49, 41, 33, 25, 17, 9, 1,

        59, 51, 43, 35, 27, 19, 11, 3,

        61, 53, 45, 37, 29, 21, 13, 5,

        63, 55, 47, 39, 31, 23, 15, 7,

    };

    private static final byte[] FP = {

        40, 8, 48, 16, 56, 24, 64, 32,

        39, 7, 47, 15,  55, 23, 63, 31,

        38, 6, 46, 14, 54, 22, 62, 30,

        37, 5, 45, 13, 53, 21, 61, 29,

        36, 4, 44, 12, 52, 20, 60, 28,

        35, 3, 43, 11, 51, 19, 59, 27,

        34, 2, 42, 10, 50, 18, 58, 26,

        33, 1, 41, 9, 49, 17, 57, 25,

    };

    private static final byte[] PC1_C = {

        57, 49, 41, 33, 25, 17, 9,

        1, 58, 50, 42, 34, 26, 18,

        10, 2, 59, 51, 43, 35, 27,

        19, 11, 3, 60, 52, 44, 36,

    };

    private static final byte[] PC1_D = {

        63, 55, 47, 39, 31, 23, 15,

        7, 62, 54, 46, 38, 30, 22,

        14, 6, 61, 53, 45, 37, 29,

        21, 13, 5, 28, 20, 12, 4,

    };

    private static final byte[] shifts = { 1,1,2,2,2,2,2,2,1,2,2,2,2,2,2,1, };

    private static final byte[] PC2_C = {

        14, 17, 11, 24, 1, 5,

        3, 28, 15, 6, 21, 10,

        23, 19, 12, 4, 26, 8,

        16, 7, 27, 20, 13, 2,

    };

    private static final byte[] PC2_D = {

        41,52,31,37,47,55,

        30,40,51,45,33,48,

        44,49,39,56,34,53,

        46,42,50,36,29,32,

    };

    private byte[] C = new byte[28];

    private byte[] D = new byte[28];

    private byte[] KS;

    private byte[] E = new byte[48];

    private static final byte[] e2 = {

        32, 1, 2, 3, 4, 5,

        4, 5, 6, 7, 8, 9,

        8, 9,10,11,12,13,

        12,13,14,15,16,17,

        16,17,18,19,20,21,

        20,21,22,23,24,25,

        24,25,26,27,28,29,

        28,29,30,31,32, 1,

    };

    private void setkey(byte[] key) {

        int i, j, k;

        byte t;

        if (KS == null) {

            KS = new byte[16*48];

        }

        for (i = 0; i < 28; i++) {

                C[i] = key[PC1_C[i]-1];

                D[i] = key[PC1_D[i]-1];

        }

        for (i = 0; i < 16; i++) {

                for (k = 0; k < shifts[i]; k++) {

                        t = C[0];

                        for (j = 0; j < 28-1; j++)

                                C[j] = C[j+1];

                        C[27] = t;

                        t = D[0];

                        for (j = 0; j < 28-1; j++)

                                D[j] = D[j+1];

                        D[27] = t;

                }

                for (j = 0; j < 24; j++) {

                        int index = i * 48;

                        KS[index+j] = C[PC2_C[j]-1];

                        KS[index+j+24] = D[PC2_D[j]-28-1];

                }

        }

        for (i = 0; i < 48; i++)

                E[i] = e2[i];

    }

    private static final byte[][] S = {

        {14, 4,13, 1, 2,15,11, 8, 3,10, 6,12, 5, 9, 0, 7,

        0,15, 7, 4,14, 2,13, 1,10, 6,12,11, 9, 5, 3, 8,

        4, 1,14, 8,13, 6, 2,11,15,12, 9, 7, 3,10, 5, 0,

        15,12, 8, 2, 4, 9, 1, 7, 5,11, 3,14,10, 0, 6,13},

        {15, 1, 8,14, 6,11, 3, 4, 9, 7, 2,13,12, 0, 5,10,

        3,13, 4, 7,15, 2, 8,14,12, 0, 1,10, 6, 9,11, 5,

        0,14, 7,11,10, 4,13, 1, 5, 8,12, 6, 9, 3, 2,15,

        13, 8,10, 1, 3,15, 4, 2,11, 6, 7,12, 0, 5,14, 9},

        {10, 0, 9,14, 6, 3,15, 5, 1,13,12, 7,11, 4, 2, 8,

        13, 7, 0, 9, 3, 4, 6,10, 2, 8, 5,14,12,11,15, 1,

        13, 6, 4, 9, 8,15, 3, 0,11, 1, 2,12, 5,10,14, 7,

         1,10,13, 0, 6, 9, 8, 7, 4,15,14, 3,11, 5, 2,12},

        {7,13,14, 3, 0, 6, 9,10, 1, 2, 8, 5,11,12, 4,15,

        13, 8,11, 5, 6,15, 0, 3, 4, 7, 2,12, 1,10,14, 9,

        10, 6, 9, 0,12,11, 7,13,15, 1, 3,14, 5, 2, 8, 4,

         3,15, 0, 6,10, 1,13, 8, 9, 4, 5,11,12, 7, 2,14},

        {2,12, 4, 1, 7,10,11, 6, 8, 5, 3,15,13, 0,14, 9,

        14,11, 2,12, 4, 7,13, 1, 5, 0,15,10, 3, 9, 8, 6,

         4, 2, 1,11,10,13, 7, 8,15, 9,12, 5, 6, 3, 0,14,

        11, 8,12, 7, 1,14, 2,13, 6,15, 0, 9,10, 4, 5, 3},

        {12, 1,10,15, 9, 2, 6, 8, 0,13, 3, 4,14, 7, 5,11,

        10,15, 4, 2, 7,12, 9, 5, 6, 1,13,14, 0,11, 3, 8,

         9,14,15, 5, 2, 8,12, 3, 7, 0, 4,10, 1,13,11, 6,

         4, 3, 2,12, 9, 5,15,10,11,14, 1, 7, 6, 0, 8,13},

        {4,11, 2,14,15, 0, 8,13, 3,12, 9, 7, 5,10, 6, 1,

        13, 0,11, 7, 4, 9, 1,10,14, 3, 5,12, 2,15, 8, 6,

         1, 4,11,13,12, 3, 7,14,10,15, 6, 8, 0, 5, 9, 2,

         6,11,13, 8, 1, 4,10, 7, 9, 5, 0,15,14, 2, 3,12},

        {13, 2, 8, 4, 6,15,11, 1,10, 9, 3,14, 5, 0,12, 7,

         1,15,13, 8,10, 3, 7, 4,12, 5, 6,11, 0,14, 9, 2,

         7,11, 4, 1, 9,12,14, 2, 0, 6,10,13,15, 3, 5, 8,

         2, 1,14, 7, 4,10, 8,13,15,12, 9, 0, 3, 5, 6,11},

    };

    private static final byte[] P = {

        16, 7,20,21,

        29,12,28,17,

         1,15,23,26,

         5,18,31,10,

         2, 8,24,14,

        32,27, 3, 9,

        19,13,30, 6,

        22,11, 4,25,

    };

    private byte[]  L = new byte[64];

    private byte[] tempL = new byte[32];

    private byte[] f = new byte[32];

    private byte[] preS = new byte[48];

    private void encrypt(byte[] block,int fake) {

        int     i;

        int t, j, k;

        int R = 32; // &L[32]

        if (KS == null) {

            KS = new byte[16*48];

        }

        for(j=0; j < 64; j++) {

            L[j] = block[IP[j]-1];

        }

        for(i=0; i < 16; i++) {

            int index = i * 48;

            for(j=0; j < 32; j++) {

                tempL[j] = L[R+j];

            }

            for(j=0; j < 48; j++) {

                preS[j] = (byte) (L[R+E[j]-1] ^ KS[index+j]);

            }

            for(j=0; j < 8; j++) {

                t = 6*j;

                k = S[j][(preS[t+0]<<5)+

                         (preS[t+1]<<3)+

                         (preS[t+2]<<2)+

                         (preS[t+3]<<1)+

                         (preS[t+4]<<0)+

                         (preS[t+5]<<4)];

                t = 4*j;

                f[t+0] = (byte) ((k>>3)&01);

                f[t+1] = (byte) ((k>>2)&01);

                f[t+2] = (byte) ((k>>1)&01);

                f[t+3] = (byte) ((k>>0)&01);

            }

            for(j=0; j < 32; j++) {

                        L[R+j] = (byte) (L[j] ^ f[P[j]-1]);

            }

            for(j=0; j < 32; j++) {

                        L[j] = tempL[j];

            }

        }

        for(j=0; j < 32; j++) {

            t = L[j];

            L[j] = L[R+j];

            L[R+j] = (byte)t;

        }

        for(j=0; j < 64; j++) {

                block[j] = L[FP[j]-1];

        }

    }

/* EXPORT DELETE END */

    /**

     * Creates a new Crypt object for use with the crypt method.

     *

     */

    public Crypt()

    {

        // does nothing at this time

        super();

    }

    /**

     * Implements the libc crypt(3) function.

     *

     * @param pw the password to "encrypt".

     *

     * @param salt the salt to use.

     *

     * @return A new byte[13] array that contains the encrypted

     * password. The first two characters are the salt.

     *

     */

    public synchronized byte[] crypt(byte[] pw, byte[] salt) {

        int c, i, j, pwi;

        byte temp;

        byte[] block = new byte[66];

        byte[] iobuf = new byte[13];

/* EXPORT DELETE START */

        pwi = 0;

        for(i=0; pwi < pw.length && i < 64; pwi++) {

            c = pw[pwi];

            for(j=0; j < 7; j++, i++) {

                block[i] = (byte) ((c>>(6-j)) & 01);

            }

            i++;

        }

        setkey(block);

        for(i=0; i < 66; i++) {

            block[i] = 0;

        }

        for(i=0; i < 2; i++) {

            c = salt[i];

            iobuf[i] = (byte)c;

            if(c > 'Z')

                c -= 6;

            if(c > '9')

                c -= 7;

            c -= '.';

            for(j=0; j < 6; j++) {

                if( ((c>>j) & 01) != 0) {

                    temp = E[6*i+j];

                    E[6*i+j] = E[6*i+j+24];

                    E[6*i+j+24] = temp;

                }

            }

        }

        for(i=0; i < 25; i++) {

                encrypt(block,0);

        }

        for(i=0; i < 11; i++) {

            c = 0;

            for(j=0; j < 6; j++) {

                c <<= 1;

                c |= block[6*i+j];

            }

            c += '.';

            if(c > '9') {

                c += 7;

            }

            if(c > 'Z') {

                c += 6;

            }

            iobuf[i+2] = (byte)c;

        }

        //iobuf[i+2] = 0;

        if(iobuf[1] == 0) {

            iobuf[1] = iobuf[0];

        }

/* EXPORT DELETE END */

        return(iobuf);

    }

    /**

     * program to test the crypt routine.

     *

     * The first parameter is the cleartext password, the second is

     * the salt to use. The salt should be two characters from the

     * set [a-zA-Z0-9./]. Outputs the crypt result.

     *

     * @param arg command line arguments.

     *

     */

    public static void main(String[] arg) {

        if (arg.length!=2) {

            System.err.println("usage: Crypt password salt");

            System.exit(1);

        }

        Crypt c = new Crypt();

        try {

            byte[] result = c.crypt

                (arg[0].getBytes("ISO-8859-1"), arg[1].getBytes("ISO-8859-1"));

            for (int i=0; i<result.length; i++) {

                System.out.println(" "+i+" "+(char)result[i]);

            }

        } catch (java.io.UnsupportedEncodingException uee) {

            // cannot happen

        }

    }

}