/*
* Created on 19-Jan-2006
* Created by Paul Gardner
* Copyright (C) 2006 Aelitis, All Rights Reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
* This program 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 for more details.
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*
* AELITIS, SAS au capital de 46,603.30 euros
* 8 Allee Lenotre, La Grille Royale, 78600 Le Mesnil le Roi, France.
*
*/
package com.aelitis.azureus.core.networkmanager.impl;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.security.spec.AlgorithmParameterSpec;
import javax.crypto.Cipher;
import javax.crypto.spec.SecretKeySpec;
import org.bouncycastle.crypto.CipherParameters;
import org.bouncycastle.crypto.engines.RC4Engine;
import org.bouncycastle.crypto.params.KeyParameter;
import org.gudy.azureus2.core3.util.Debug;
public class
TransportCipher
{
private static boolean internal_rc4 = true; // force internal as we want 160 bit and JCE no supports it
private Cipher cipher;
private RC4Engine rc4_engine;
public
TransportCipher(
String algorithm,
int mode,
SecretKeySpec key_spec,
AlgorithmParameterSpec params )
throws Exception
{
cipher = Cipher.getInstance( algorithm );
cipher.init( mode, key_spec, params );
}
TransportCipher(
String algorithm,
int mode,
SecretKeySpec key_spec )
throws Exception
{
if ( algorithm.equals( "RC4" )){
if ( !internal_rc4 ){
try{
cipher = Cipher.getInstance( algorithm );
cipher.init( mode, key_spec );
}catch( Throwable e ){
internal_rc4 = true;
}
}
if ( internal_rc4 ){
rc4_engine = new RC4Engine();
CipherParameters params = new KeyParameter(key_spec.getEncoded());
rc4_engine.init( mode == Cipher.ENCRYPT_MODE, params );
}
//System.out.println( "RC4 key: " + ByteFormatter.encodeString( key_spec.getEncoded()));
// skip first 1024 bytes of stream to protected against a Fluhrer, Mantin and Shamir attack
byte[] temp = new byte[1024];
temp = update( temp );
//System.out.println( "RC4: first discard = " + ByteFormatter.encodeString( temp, 0, 4 ));
}else{
cipher = Cipher.getInstance( algorithm );
cipher.init( mode, key_spec );
}
}
protected byte[]
update(
byte[] data )
{
return( update( data, 0, data.length ));
}
protected byte[]
update(
byte[] data,
int offset,
int length )
{
byte[] result;
if ( length == 0 ){
// watch out, cipher.update returns NULL with 0 length input
result = new byte[0];
}else if ( cipher != null ){
result = cipher.update( data, offset, length );
}else{
result = new byte[length];
rc4_engine.processBytes( data, offset, length, result, 0 );
}
return( result );
}
protected void
update(
ByteBuffer source_buffer,
ByteBuffer target_buffer )
throws IOException
{
try{
// TODO: 1.5 supports update( ByteBuffer, ByteBuffer )
byte[] source_bytes;
int offset;
int length = source_buffer.remaining();
if ( source_buffer.hasArray()){
source_bytes = source_buffer.array();
offset = source_buffer.arrayOffset() + source_buffer.position();
}else{
source_bytes = new byte[length];
offset = 0;
source_buffer.get( source_bytes );
}
byte[] target_bytes = update( source_bytes, offset, length );
source_buffer.position( source_buffer.limit());
target_buffer.put( target_bytes );
}catch( Throwable e ){
throw( new IOException( Debug.getNestedExceptionMessage( e )));
}
}
public String
getName()
{
if ( cipher != null ){
String s = cipher.getAlgorithm();
int pos = s.indexOf("/");
if ( pos != -1 ){
s = s.substring(0,pos);
}
if ( s.equals( "RC4" )){
s = "RC4-160";
}else{
s += "-" + cipher.getBlockSize()*8;
}
return( s );
}else{
return( "RC4-160" );
}
}
}