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/*
* Copyright (c) 2006-2011 Christian Plattner. All rights reserved.
* Please refer to the LICENSE.txt for licensing details.
*/
package ch.ethz.ssh2.crypto.cipher;
import java.util.ArrayList;
import java.util.List;
import java.util.Vector;
/**
* BlockCipherFactory.
*
* @author Christian Plattner
* @version $Id: BlockCipherFactory.java 29 2011-05-28 21:28:32Z dkocher@sudo.ch $
*/
public class BlockCipherFactory
{
private static final class CipherEntry
{
String type;
int blocksize;
int keysize;
String cipherClass;
public CipherEntry(String type, int blockSize, int keySize, String cipherClass)
{
this.type = type;
this.blocksize = blockSize;
this.keysize = keySize;
this.cipherClass = cipherClass;
}
}
private static final List<CipherEntry> ciphers = new Vector<CipherEntry>();
static
{
/* Higher Priority First */
ciphers.add(new CipherEntry("aes128-ctr", 16, 16, "ch.ethz.ssh2.crypto.cipher.AES"));
ciphers.add(new CipherEntry("aes192-ctr", 16, 24, "ch.ethz.ssh2.crypto.cipher.AES"));
ciphers.add(new CipherEntry("aes256-ctr", 16, 32, "ch.ethz.ssh2.crypto.cipher.AES"));
ciphers.add(new CipherEntry("blowfish-ctr", 8, 16, "ch.ethz.ssh2.crypto.cipher.BlowFish"));
ciphers.add(new CipherEntry("aes128-cbc", 16, 16, "ch.ethz.ssh2.crypto.cipher.AES"));
ciphers.add(new CipherEntry("aes192-cbc", 16, 24, "ch.ethz.ssh2.crypto.cipher.AES"));
ciphers.add(new CipherEntry("aes256-cbc", 16, 32, "ch.ethz.ssh2.crypto.cipher.AES"));
ciphers.add(new CipherEntry("blowfish-cbc", 8, 16, "ch.ethz.ssh2.crypto.cipher.BlowFish"));
ciphers.add(new CipherEntry("3des-ctr", 8, 24, "ch.ethz.ssh2.crypto.cipher.DESede"));
ciphers.add(new CipherEntry("3des-cbc", 8, 24, "ch.ethz.ssh2.crypto.cipher.DESede"));
}
public static String[] getDefaultCipherList()
{
List<String> list = new ArrayList<String>(ciphers.size());
for (CipherEntry ce : ciphers)
{
list.add(ce.type);
}
return list.toArray(new String[ciphers.size()]);
}
public static void checkCipherList(String[] cipherCandidates)
{
for (String cipherCandidate : cipherCandidates)
{
getEntry(cipherCandidate);
}
}
// @SuppressWarnings("rawtypes")
public static BlockCipher createCipher(String type, boolean encrypt, byte[] key, byte[] iv)
{
try
{
CipherEntry ce = getEntry(type);
Class cc = Class.forName(ce.cipherClass);
BlockCipher bc = (BlockCipher) cc.newInstance();
if (type.endsWith("-cbc"))
{
bc.init(encrypt, key);
return new CBCMode(bc, iv, encrypt);
}
else if (type.endsWith("-ctr"))
{
bc.init(true, key);
return new CTRMode(bc, iv, encrypt);
}
throw new IllegalArgumentException("Cannot instantiate " + type);
}
catch (ClassNotFoundException e)
{
throw new IllegalArgumentException("Cannot instantiate " + type, e);
}
catch (InstantiationException e)
{
throw new IllegalArgumentException("Cannot instantiate " + type, e);
}
catch (IllegalAccessException e)
{
throw new IllegalArgumentException("Cannot instantiate " + type, e);
}
}
private static CipherEntry getEntry(String type)
{
for (CipherEntry ce : ciphers)
{
if (ce.type.equals(type))
{
return ce;
}
}
throw new IllegalArgumentException("Unkown algorithm " + type);
}
public static int getBlockSize(String type)
{
CipherEntry ce = getEntry(type);
return ce.blocksize;
}
public static int getKeySize(String type)
{
CipherEntry ce = getEntry(type);
return ce.keysize;
}
}
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