/*
 * Copyright (C) 2013 The WLANAudit project contributors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package es.glasspixel.wlanaudit.keyframework;

import java.util.ArrayList;
import java.util.List;


/**
 * Default key calculator for Huawei AP's Based on the algorithm documented at
 * http://websec.ca/blog/view/mac2wepkey_huawei
 *
 * @author Roberto Estrada
 */
public class HWeiKeyCalculator implements IKeyCalculator {

    final int[] a0 = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
    final int[] a1 = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15};
    final int[] a2 = {0, 13, 10, 7, 5, 8, 15, 2, 10, 7, 0, 13, 15, 2, 5, 8};
    final int[] a3 = {0, 1, 3, 2, 7, 6, 4, 5, 15, 14, 12, 13, 8, 9, 11, 10};
    final int[] a5 = {0, 4, 8, 12, 0, 4, 8, 12, 0, 4, 8, 12, 0, 4, 8, 12};
    final int[] a7 = {0, 8, 0, 8, 1, 9, 1, 9, 2, 10, 2, 10, 3, 11, 3, 11};
    final int[] a8 = {0, 5, 11, 14, 6, 3, 13, 8, 12, 9, 7, 2, 10, 15, 1, 4};
    final int[] a10 = {0, 14, 13, 3, 11, 5, 6, 8, 6, 8, 11, 5, 13, 3, 0, 14};
    final int[] a14 = {0, 1, 3, 2, 7, 6, 4, 5, 14, 15, 13, 12, 9, 8, 10, 11};
    final int[] a15 = {0, 1, 3, 2, 6, 7, 5, 4, 13, 12, 14, 15, 11, 10, 8, 9};
    final int[] n5 = {0, 5, 1, 4, 6, 3, 7, 2, 12, 9, 13, 8, 10, 15, 11, 14};
    final int[] n6 = {0, 14, 4, 10, 11, 5, 15, 1, 6, 8, 2, 12, 13, 3, 9, 7};
    final int[] n7 = {0, 9, 0, 9, 5, 12, 5, 12, 10, 3, 10, 3, 15, 6, 15, 6};
    final int[] n11 = {0, 14, 13, 3, 9, 7, 4, 10, 6, 8, 11, 5, 15, 1, 2, 12};
    final int[] n12 = {0, 13, 10, 7, 4, 9, 14, 3, 10, 7, 0, 13, 14, 3, 4, 9};
    final int[] n13 = {0, 1, 3, 2, 6, 7, 5, 4, 15, 14, 12, 13, 9, 8, 10, 11};
    final int[] n14 = {0, 1, 3, 2, 4, 5, 7, 6, 12, 13, 15, 14, 8, 9, 11, 10};
    final int[] n31 = {0, 10, 4, 14, 9, 3, 13, 7, 2, 8, 6, 12, 11, 1, 15, 5};
    final int[] key = {30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 61, 62, 63, 64, 65, 66};

    @Override
    public List<String> getKey(NetData network) {
        String trimmedBSSID = network.BSSID.replaceAll(":", "").toLowerCase();
        List<String> result;

        int i = 0;
        int[] mac = new int[12];
        while (i < 12) {
            mac[i] = Integer.parseInt(trimmedBSSID.substring(i, i + 1), 16);
            i++;
        }

        int ya = (a2[mac[0]]) ^ (n11[mac[1]]) ^ (a7[mac[2]]) ^ (a8[mac[3]]) ^ (a14[mac[4]])
                ^ (a5[mac[5]]) ^ (a5[mac[6]]) ^ (a2[mac[7]]) ^ (a0[mac[8]]) ^ (a1[mac[9]])
                ^ (a15[mac[10]]) ^ (a0[mac[11]]) ^ 13;
        int yb = (n5[mac[0]]) ^ (n12[mac[1]]) ^ (a5[mac[2]]) ^ (a7[mac[3]]) ^ (a2[mac[4]])
                ^ (a14[mac[5]]) ^ (a1[mac[6]]) ^ (a5[mac[7]]) ^ (a0[mac[8]]) ^ (a0[mac[9]])
                ^ (n31[mac[10]]) ^ (a15[mac[11]]) ^ 4;
        int yc = (a3[mac[0]]) ^ (a5[mac[1]]) ^ (a2[mac[2]]) ^ (a10[mac[3]]) ^ (a7[mac[4]])
                ^ (a8[mac[5]]) ^ (a14[mac[6]]) ^ (a5[mac[7]]) ^ (a5[mac[8]]) ^ (a2[mac[9]])
                ^ (a0[mac[10]]) ^ (a1[mac[11]]) ^ 7;
        int yd = (n6[mac[0]]) ^ (n13[mac[1]]) ^ (a8[mac[2]]) ^ (a2[mac[3]]) ^ (a5[mac[4]])
                ^ (a7[mac[5]]) ^ (a2[mac[6]]) ^ (a14[mac[7]]) ^ (a1[mac[8]]) ^ (a5[mac[9]])
                ^ (a0[mac[10]]) ^ (a0[mac[11]]) ^ 14;
        int ye = (n7[mac[0]]) ^ (n14[mac[1]]) ^ (a3[mac[2]]) ^ (a5[mac[3]]) ^ (a2[mac[4]])
                ^ (a10[mac[5]]) ^ (a7[mac[6]]) ^ (a8[mac[7]]) ^ (a14[mac[8]]) ^ (a5[mac[9]])
                ^ (a5[mac[10]]) ^ (a2[mac[11]]) ^ 7;

        result = new ArrayList<String>();
        result.add(Integer.toString(key[ya]) + Integer.toString(key[yb])
                + Integer.toString(key[yc]) + Integer.toString(key[yd]) + Integer.toString(key[ye]));

        return result;
    }

}