package com.blunk.security;

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

/**
 * Used to decipher incomming packets from the Habbo V5 Client. Credits to Matthew Parlane for
 * original class.
 * 
 * @author Mike
 */

public class RC4
{
	private int j;
	private int i;
	private static final char HEXALPHABET_CHARS[] = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F' };
	private int pSBox[];
	private int pKey[];
	private final int pArtificialKey[] = { 108, 214, 122, 91, 114, 79, 16, 141, 115, 222, 207, 216, 238, 65, 59, 50, 186, 70, 42, 248, 107, 12, 33, 247, 66, 79, 53, 216, 159, 81, 145, 249, 179, 111, 233, 56, 49, 251, 123, 162, 26, 46, 182, 96, 208, 93,
			114, 202, 255, 19, 164, 208, 79, 91, 241, 128, 158, 25, 252, 194, 217, 120, 22, 44, 1, 253, 45, 91, 113, 89, 203, 80, 34, 112, 99, 82, 103, 8, 90, 240, 39, 17, 230, 232, 80, 180, 173, 164, 112, 33, 217, 155, 170, 41, 187, 156, 213, 199, 176,
			180, 177, 236, 167, 128, 31, 155, 210, 208, 55, 198, 5, 243, 27, 48, 78, 13, 142, 64, 80, 21, 18, 19, 175, 252, 126, 194, 111, 190, 99, 94, 184, 248, 167, 77, 45, 5, 141, 128, 72, 0, 45, 107, 88, 140, 147, 30, 248, 243, 208, 82, 137, 181, 69,
			177, 8, 216, 25, 3, 239, 179, 160, 159, 129, 135, 23, 62, 192, 90, 91, 172, 119, 255, 55, 39, 78, 216, 12, 188, 45, 204, 93, 54, 30, 165, 129, 78, 151, 253, 92, 31, 196, 126, 4, 72, 182, 180, 216, 144, 78, 255, 185, 228, 134, 92, 103, 81, 2,
			144, 123, 161, 101, 187, 145, 187, 171, 62, 21, 244, 17, 231, 203, 120, 176, 87, 150, 89, 244, 7, 29, 21, 235, 165, 86, 125, 184, 90, 232, 232, 145, 15, 198, 165, 103, 12, 245, 177, 151, 29, 45, 26, 184, 91, 20, 16, 231, 174, 237, 207, 165,
			251, 114, 185, 245, 68, 82, 116, 216, 0, 203, 89, 234, 174, 100, 220, 60, 42, 60, 103, 17, 93, 208, 72, 242, 116, 148, 84, 230, 115, 56, 138, 134, 107, 199, 17, 73, 58, 75, 187, 200, 253, 141, 249, 246, 74, 201, 166, 194, 156, 72, 221, 20, 6,
			91, 191, 243, 100, 3, 113, 79, 59, 175, 94, 112, 81, 69, 166, 145, 89, 163, 111, 180, 110, 146, 156, 43, 206, 248, 22, 188, 27, 123, 152, 65, 136, 212, 185, 83, 104, 162, 69, 21, 208, 116, 78, 193, 2, 179, 222, 109, 66, 75, 56, 46, 21, 105,
			140, 236, 13, 78, 58, 30, 55, 114, 228, 96, 156, 89, 179, 116, 30, 63, 7, 52, 10, 182, 25, 87, 29, 166, 75, 64, 89, 30, 110, 40, 50, 121, 107, 44, 151, 246, 147, 131, 39, 105, 227, 58, 66, 56, 82, 107, 73, 91, 133, 210, 202, 174, 56, 108, 29,
			117, 109, 128, 103, 237, 227, 13, 138, 177, 180, 146, 142, 82, 83, 115, 194, 148, 62, 74, 92, 154, 95, 194, 104, 216, 2, 166, 59, 150, 137, 164, 49, 189, 33, 236, 46, 82, 169, 73, 77, 177, 81, 67, 98, 181, 116, 49, 76, 97, 204, 227, 29, 203,
			113, 110, 242, 255, 140, 46, 204, 144, 39, 234, 167, 30, 150, 110, 219, 138, 136, 88, 12, 179, 71, 23, 150, 233, 80, 217, 244, 248, 111, 65, 255, 69, 217, 55, 49, 43, 228, 225, 10, 123, 71, 41, 173, 7, 15, 194, 8, 87, 209, 75, 212, 179, 144,
			151, 48, 134, 47, 109, 212, 8, 24, 66, 102, 198, 211, 35, 184, 154, 76, 147, 170, 90, 247, 53, 31, 164, 5, 189, 12, 208, 99, 185, 52, 74, 154, 137, 235, 112, 132, 5, 16, 65, 124, 87, 109, 83, 170, 37, 20, 88, 134, 2, 86, 218, 169, 222, 128,
			202, 28, 87, 81, 154, 199, 124, 239, 130, 47, 88, 219, 61, 97, 18, 95, 81, 144, 123, 64, 49, 239, 24, 87, 134, 24, 102, 230, 169, 145, 83, 11, 126, 166, 230, 149, 31, 164, 94, 197, 27, 225, 35, 17, 24, 241, 140, 17, 42, 10, 40, 124, 217, 114,
			116, 252, 232, 55, 77, 88, 75, 5, 48, 180, 220, 218, 124, 97, 177, 184, 192, 205, 59, 54, 89, 152, 79, 6, 64, 29, 167, 155, 62, 14, 197, 181, 66, 142, 153, 91, 230, 43, 96, 110, 122, 187, 235, 209, 190, 241, 128, 50, 23, 53, 114, 43, 111,
			106, 99, 15, 232, 115, 101, 210, 234, 245, 238, 164, 56, 123, 94, 125, 223, 97, 210, 151, 91, 204, 4, 72, 140, 41, 143, 19, 93, 212, 153, 102, 182, 243, 102, 93, 214, 32, 68, 236, 146, 92, 168, 99, 46, 150, 249, 34, 177, 203, 105, 126, 129,
			43, 156, 166, 3, 168, 43, 81, 183, 131, 168, 111, 131, 157, 155, 195, 195, 177, 47, 180, 82, 61, 225, 62, 150, 176, 212, 191, 129, 117, 98, 72, 173, 192, 36, 203, 15, 224, 254, 52, 127, 174, 231, 38, 213, 239, 120, 52, 178, 101, 97, 132, 130,
			144, 152, 251, 226, 90, 18, 233, 74, 41, 88, 28, 17, 58, 177, 84, 226, 119, 241, 25, 192, 7, 157, 125, 170, 188, 191, 186, 75, 97, 225, 115, 184, 100, 168, 133, 0, 220, 95, 160, 242, 14, 185, 219, 214, 108, 157, 142, 32, 135, 69, 86, 64, 90,
			236, 179, 137, 64, 128, 214, 63, 132, 152, 177, 167, 158, 8, 122, 139, 89, 115, 11, 27, 85, 94, 45, 12, 164, 18, 169, 213, 74, 196, 61, 55, 60, 238, 33, 77, 181, 88, 166, 61, 96, 152, 139, 209, 42, 223, 203, 149, 25, 93, 71, 132, 40, 77, 31,
			187, 168, 88, 210, 106, 251, 181, 29, 15, 158, 194, 183, 176, 230, 91, 2, 124, 174, 86, 165, 57, 108, 191, 227, 106, 164, 159, 110, 35, 205, 248, 254, 105, 129, 25, 77, 6, 164, 93, 176, 192, 205, 26, 96, 109, 191, 35, 239, 46, 124, 53, 208,
			221, 175, 169, 246, 68, 228, 158, 39, 221, 66, 234, 170, 154, 6, 192, 132, 25, 6, 168, 169, 26, 251, 183, 23, 204, 192, 34, 96, 126, 20, 183, 135, 20, 223, 115, 137, 254, 247, 13, 71, 7, 176, 162, 184, 184, 255, 128, 229, 236, 107, 42, 80,
			68, 112, 127, 4, 57, 89, 26, 78, 251, 177, 21, 151, 224, 26, 227, 112, 78, 240, 11, 247, 87, 103 };
	
	/**
	 * Constructor
	 * 
	 * @param tPublicKey The Public Key Decoded (Since, we don't decode the key within the RC4
	 * class! - We do that elsewhere using FuseSecret!)
	 */
	public RC4(int tPublicKeyDecode)
	{
		this.pSBox = new int[256];
		this.pKey = new int[256];
		this.i = 0;
		this.j = 0;
		
		// Setup the pSBox (It's the table!)
		this.init(tPublicKeyDecode);
	}
	
	/**
	 * Sets up the Encryption tables ready to encipher/decipher!
	 */
	@SuppressWarnings("unchecked")
	private void init(int tKey)
	{
		String keyStr = Integer.toString(tKey);
		
		for (int i = 0; i < 256; i++)
		{
			char meep = keyStr.charAt(i % keyStr.length());
			pKey[i] = Character.getNumericValue(meep);
			pSBox[i] = i;
		}
		
		int keyLength = (tKey & 31);
		if (keyLength < 20)
			keyLength += 20;
		
		int keyOffset = (tKey % 1024);
		
		int prevKey = 0, keySkip = 0, nKey = 0;
		List cKey = new LinkedList();
		cKey = new ArrayList();
		
		for (int i = 0; i < 256; i++)
		{
			keySkip = ((i % 3) + (prevKey % 39));
			nKey = pArtificialKey[(keyOffset + i + keySkip) % (pArtificialKey.length)];
			prevKey = nKey;
			cKey.add(Integer.toString(nKey));
		}
		
		for (int i = 0; i < 256; i++)
		{
			Object tmp = cKey.get(i % keyLength);
			pKey[i] = Integer.parseInt(tmp.toString());
			pSBox[i] = i;
		}
		
		int k = 0;
		j = 0;
		
		for (int i = 0; i < 256; i++)
		{
			j = (j + pSBox[i] + pKey[i]) % 256;
			k = pSBox[i];
			pSBox[i] = pSBox[j];
			pSBox[j] = k;
		}
		
		i = 0;
		j = 0;
		
	}
	
	/**
	 * Just for me, I, Mike, to do some hardc0re debugging!
	 */
	public void DebugTables()
	{
		for (int i = 0; i < pSBox.length; i++)
		{
			System.out.println("pSBox[" + Integer.toString(i) + "] = " + Integer.toString(pSBox[i]));
		}
	}
	
	public char[] decipher(char[] data)
	{
		char[] result = new char[data.length / 2];
		for (int x = 0, z = 0; x < data.length; x += 2, z++)
		{
			int t = RC4.hexToByte(data[x], data[x + 1]);
			result[z] = (char)(t ^ moveUp());
		}
		
		return result;
	}
	
	private int moveUp()
	{
		i = (i + 1) % 256;
		j = (j + pSBox[i]) % 256;
		int swap = pSBox[i];
		pSBox[i] = pSBox[j];
		pSBox[j] = swap;
		return pSBox[(pSBox[i] + pSBox[j]) % 256];
	}
	
	/**
	 * Very fast method for converting two hex bytes to the original byte.
	 * @param A The first byte.
	 * @param B The second byte.
	 * @return The result of the two bytes.
	 */
	 private static int hexToByte(char A, char B)
     {
         int C = 0; // The output value
         int D = 0; // Counter used for determining hex value

         while (D < HEXALPHABET_CHARS.length)
         {
             if (HEXALPHABET_CHARS[D] == (A & 0xff))
             {
                 C = (D << 4);
                 break;
             }
             D++;
         }

         D = 0;
         while (D < HEXALPHABET_CHARS.length)
         {
             if (HEXALPHABET_CHARS[D] == (B & 0xff))
             {
                 C += D;
                 break;
             }
             D++;
         }

         return C;
     }
}