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      1 /*
      2  * Copyright (c) 2006-2011 Christian Plattner. All rights reserved.
      3  * Please refer to the LICENSE.txt for licensing details.
      4  */
      5 package ch.ethz.ssh2.crypto.cipher;
      6 
      7 import java.util.ArrayList;
      8 import java.util.List;
      9 import java.util.Vector;
     10 
     11 /**
     12  * BlockCipherFactory.
     13  *
     14  * @author Christian Plattner
     15  * @version $Id: BlockCipherFactory.java 29 2011-05-28 21:28:32Z dkocher (at) sudo.ch $
     16  */
     17 public class BlockCipherFactory
     18 {
     19 	private static final class CipherEntry
     20 	{
     21 		String type;
     22 		int blocksize;
     23 		int keysize;
     24 		String cipherClass;
     25 
     26 		public CipherEntry(String type, int blockSize, int keySize, String cipherClass)
     27 		{
     28 			this.type = type;
     29 			this.blocksize = blockSize;
     30 			this.keysize = keySize;
     31 			this.cipherClass = cipherClass;
     32 		}
     33 	}
     34 
     35 	private static final List<CipherEntry> ciphers = new Vector<CipherEntry>();
     36 
     37 	static
     38 	{
     39 		/* Higher Priority First */
     40 		ciphers.add(new CipherEntry("aes128-ctr", 16, 16, "ch.ethz.ssh2.crypto.cipher.AES"));
     41 		ciphers.add(new CipherEntry("aes192-ctr", 16, 24, "ch.ethz.ssh2.crypto.cipher.AES"));
     42 		ciphers.add(new CipherEntry("aes256-ctr", 16, 32, "ch.ethz.ssh2.crypto.cipher.AES"));
     43 		ciphers.add(new CipherEntry("blowfish-ctr", 8, 16, "ch.ethz.ssh2.crypto.cipher.BlowFish"));
     44 
     45 		ciphers.add(new CipherEntry("aes128-cbc", 16, 16, "ch.ethz.ssh2.crypto.cipher.AES"));
     46 		ciphers.add(new CipherEntry("aes192-cbc", 16, 24, "ch.ethz.ssh2.crypto.cipher.AES"));
     47 		ciphers.add(new CipherEntry("aes256-cbc", 16, 32, "ch.ethz.ssh2.crypto.cipher.AES"));
     48 		ciphers.add(new CipherEntry("blowfish-cbc", 8, 16, "ch.ethz.ssh2.crypto.cipher.BlowFish"));
     49 
     50 		ciphers.add(new CipherEntry("3des-ctr", 8, 24, "ch.ethz.ssh2.crypto.cipher.DESede"));
     51 		ciphers.add(new CipherEntry("3des-cbc", 8, 24, "ch.ethz.ssh2.crypto.cipher.DESede"));
     52 	}
     53 
     54 	public static String[] getDefaultCipherList()
     55 	{
     56 		List<String> list = new ArrayList<String>(ciphers.size());
     57 		for (CipherEntry ce : ciphers)
     58 		{
     59 			list.add(ce.type);
     60 		}
     61 		return list.toArray(new String[ciphers.size()]);
     62 	}
     63 
     64 	public static void checkCipherList(String[] cipherCandidates)
     65 	{
     66 		for (String cipherCandidate : cipherCandidates)
     67 		{
     68 			getEntry(cipherCandidate);
     69 		}
     70 	}
     71 
     72 	//	@SuppressWarnings("rawtypes")
     73 	public static BlockCipher createCipher(String type, boolean encrypt, byte[] key, byte[] iv)
     74 	{
     75 		try
     76 		{
     77 			CipherEntry ce = getEntry(type);
     78 			Class cc = Class.forName(ce.cipherClass);
     79 			BlockCipher bc = (BlockCipher) cc.newInstance();
     80 
     81 			if (type.endsWith("-cbc"))
     82 			{
     83 				bc.init(encrypt, key);
     84 				return new CBCMode(bc, iv, encrypt);
     85 			}
     86 			else if (type.endsWith("-ctr"))
     87 			{
     88 				bc.init(true, key);
     89 				return new CTRMode(bc, iv, encrypt);
     90 			}
     91 			throw new IllegalArgumentException("Cannot instantiate " + type);
     92 		}
     93 		catch (ClassNotFoundException e)
     94 		{
     95 			throw new IllegalArgumentException("Cannot instantiate " + type, e);
     96 		}
     97 		catch (InstantiationException e)
     98 		{
     99 			throw new IllegalArgumentException("Cannot instantiate " + type, e);
    100 		}
    101 		catch (IllegalAccessException e)
    102 		{
    103 			throw new IllegalArgumentException("Cannot instantiate " + type, e);
    104 		}
    105 	}
    106 
    107 	private static CipherEntry getEntry(String type)
    108 	{
    109 		for (CipherEntry ce : ciphers)
    110 		{
    111 			if (ce.type.equals(type))
    112 			{
    113 				return ce;
    114 			}
    115 		}
    116 		throw new IllegalArgumentException("Unkown algorithm " + type);
    117 	}
    118 
    119 	public static int getBlockSize(String type)
    120 	{
    121 		CipherEntry ce = getEntry(type);
    122 		return ce.blocksize;
    123 	}
    124 
    125 	public static int getKeySize(String type)
    126 	{
    127 		CipherEntry ce = getEntry(type);
    128 		return ce.keysize;
    129 	}
    130 }
    131