/*
* Created on 15 Jun 2006
* Created by Aaron Grunthal and 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.security.impl;
import java.nio.ByteBuffer;
import java.security.InvalidAlgorithmParameterException;
import java.security.InvalidKeyException;
import java.security.Key;
import java.security.KeyPair;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.SecureRandom;
import java.security.Signature;
import org.bouncycastle.jce.provider.JCEECDHKeyAgreement;
import com.aelitis.azureus.core.security.CryptoECCUtils;
import com.aelitis.azureus.core.security.CryptoManagerException;
import com.aelitis.azureus.core.security.CryptoSTSEngine;
/**
* STS authentication protocol using a symmetric 4 message ECDH/ECDSA handshake
*/
final class
CryptoSTSEngineImpl
implements CryptoSTSEngine
{
public static final int VERSION = 1;
private KeyPair ephemeralKeyPair;
private PublicKey myPublicKey;
private PrivateKey myPrivateKey;
private PublicKey remotePubKey;
private byte[] sharedSecret;
private InternalDH ecDH;
/**
*
* @param myIdent keypair representing our current identity
*/
CryptoSTSEngineImpl(
PublicKey _myPub,
PrivateKey _myPriv )
throws CryptoManagerException
{
myPublicKey = _myPub;
myPrivateKey = _myPriv;
ephemeralKeyPair = CryptoECCUtils.createKeys();
try{
ecDH = new InternalDH();
//ecDH = KeyAgreement.getInstance("ECDH", "BC");
ecDH.init(ephemeralKeyPair.getPrivate());
}catch (Exception e){
throw new CryptoManagerException("Couldn't initialize crypto handshake", e);
}
}
public void
getKeys(
ByteBuffer message )
throws CryptoManagerException
{
getMessage( message, true );
}
public void
putKeys(
ByteBuffer message )
throws CryptoManagerException
{
putMessage( message, true );
}
public void
getAuth(
ByteBuffer message )
throws CryptoManagerException
{
getMessage( message, false );
}
public void
putAuth(
ByteBuffer message )
throws CryptoManagerException
{
putMessage( message, false );
}
public void
putMessage(
ByteBuffer message,
boolean keys )
throws CryptoManagerException
{
// System.out.println( "put( " + keys + ") " + this );
try{
int version = getInt( message, 255 );
if ( version != VERSION ){
throw( new CryptoManagerException( "invalid version (" + version + ")" ));
}
if ( keys ){
if ( sharedSecret != null ){
throw( new CryptoManagerException( "phase error: keys already received" ));
}
final byte[] rawRemoteOtherPubkey = getBytes( message, 65535 );
final byte[] rawRemoteEphemeralPubkey = getBytes( message, 65535 );
final byte[] remoteSig = getBytes( message, 65535 );
final byte[] pad = getBytes( message, 65535 );
remotePubKey = CryptoECCUtils.rawdataToPubkey(rawRemoteOtherPubkey);
Signature check = CryptoECCUtils.getSignature(remotePubKey);
check.update(rawRemoteOtherPubkey);
check.update(rawRemoteEphemeralPubkey);
if ( check.verify(remoteSig)){
ecDH.doPhase(CryptoECCUtils.rawdataToPubkey(rawRemoteEphemeralPubkey), true);
sharedSecret = ecDH.generateSecret();
}else{
throw( new CryptoManagerException( "Signature check failed" ));
}
}else{
if ( sharedSecret == null ){
throw( new CryptoManagerException( "phase error: keys not received" ));
}
final byte[] IV = getBytes( message, 65535 );
final byte[] remoteSig = getBytes( message, 65535);
Signature check = CryptoECCUtils.getSignature( remotePubKey );
check.update(IV);
check.update(sharedSecret);
if ( !check.verify(remoteSig)){
throw( new CryptoManagerException( "Signature check failed" ));
}
}
}catch( CryptoManagerException e ){
throw( e );
}catch( Throwable e ){
throw( new CryptoManagerException( "Failed to generate message" ));
}
}
public void
getMessage(
ByteBuffer buffer,
boolean keys )
throws CryptoManagerException
{
// System.out.println( "get( " + keys + ") " + this );
try{
putInt( buffer, VERSION, 255 );
SecureRandom random = SecureRandom.getInstance("SHA1PRNG");
Signature sig = CryptoECCUtils.getSignature(myPrivateKey);
if ( keys ){
final byte[] rawMyPubkey = CryptoECCUtils.keyToRawdata(myPublicKey);
final byte[] rawEphemeralPubkey = CryptoECCUtils.keyToRawdata(ephemeralKeyPair.getPublic());
sig.update(rawMyPubkey);
sig.update(rawEphemeralPubkey);
final byte[] rawSign = sig.sign();
final byte[] pad = new byte[random.nextInt(32)];
random.nextBytes(pad);
putBytes( buffer, rawMyPubkey, 65535 );
putBytes( buffer, rawEphemeralPubkey, 65535 );
putBytes( buffer, rawSign, 65535 );
putBytes( buffer, pad, 65535 );
}else{
if ( sharedSecret == null ){
throw( new CryptoManagerException( "phase error: keys not received" ));
}
final byte[] IV = new byte[20 + random.nextInt(32)];
random.nextBytes(IV);
sig.update(IV);
sig.update(sharedSecret);
final byte[] rawSig = sig.sign();
putBytes( buffer, IV, 65535 );
putBytes( buffer, rawSig, 65535 );
}
}catch( CryptoManagerException e ){
throw( e );
}catch( Throwable e ){
throw( new CryptoManagerException( "Failed to generate message" ));
}
}
public byte[]
getSharedSecret()
throws CryptoManagerException
{
if ( sharedSecret == null ){
throw( new CryptoManagerException( "secret not yet available" ));
}
return sharedSecret;
}
public byte[]
getRemotePublicKey()
throws CryptoManagerException
{
if ( remotePubKey == null ){
throw( new CryptoManagerException( "key not yet available" ));
}
return( CryptoECCUtils.keyToRawdata( remotePubKey ));
}
protected int
getInt(
ByteBuffer buffer,
int max_size )
throws CryptoManagerException
{
try{
if ( max_size < 256 ){
return( buffer.get() & 0xff);
}else if ( max_size < 65536 ){
return( buffer.getShort() & 0xffff);
}else{
return( buffer.getInt());
}
}catch( Throwable e ){
throw( new CryptoManagerException( "Failed to get int", e ));
}
}
protected byte[]
getBytes(
ByteBuffer buffer,
int max_size )
throws CryptoManagerException
{
int len = getInt( buffer, max_size );
if ( len > max_size ){
throw( new CryptoManagerException( "Invalid length" ));
}
try{
byte[] res = new byte[len];
buffer.get( res );
return( res );
}catch( Throwable e ){
throw( new CryptoManagerException( "Failed to get byte[]", e ));
}
}
protected void
putInt(
ByteBuffer buffer,
int value,
int max_size )
throws CryptoManagerException
{
try{
if ( max_size < 256 ){
buffer.put((byte)value);
}else if ( max_size < 65536 ){
buffer.putShort((short)value );
}else{
buffer.putInt( value );
}
}catch( Throwable e ){
throw( new CryptoManagerException( "Failed to put int", e ));
}
}
protected void
putBytes(
ByteBuffer buffer,
byte[] value,
int max_size )
throws CryptoManagerException
{
putInt( buffer, value.length, max_size );
try{
buffer.put( value );
}catch( Throwable e ){
throw( new CryptoManagerException( "Failed to put byte[]", e ));
}
}
class
InternalDH
extends JCEECDHKeyAgreement.DH
{
// we use this class to obtain compatability with BC
public void
init(
Key key )
throws InvalidKeyException, InvalidAlgorithmParameterException
{
engineInit( key, null );
}
public Key
doPhase(
Key key,
boolean lastPhase )
throws InvalidKeyException, IllegalStateException
{
return( engineDoPhase( key, lastPhase ));
}
public byte[]
generateSecret()
throws IllegalStateException
{
return( engineGenerateSecret());
}
}
}