package de.gultsch.chat.crypto; import java.math.BigInteger; import java.security.KeyFactory; import java.security.KeyPair; import java.security.KeyPairGenerator; import java.security.NoSuchAlgorithmException; import java.security.PrivateKey; import java.security.PublicKey; import java.security.spec.DSAPrivateKeySpec; import java.security.spec.DSAPublicKeySpec; import java.security.spec.InvalidKeySpecException; import org.json.JSONException; import org.json.JSONObject; import android.content.Context; import android.util.Log; import de.gultsch.chat.entities.Account; import de.gultsch.chat.persistance.DatabaseBackend; import de.gultsch.chat.xml.Element; import de.gultsch.chat.xmpp.MessagePacket; import net.java.otr4j.OtrEngineHost; import net.java.otr4j.OtrException; import net.java.otr4j.OtrPolicy; import net.java.otr4j.OtrPolicyImpl; import net.java.otr4j.session.InstanceTag; import net.java.otr4j.session.SessionID; public class OtrEngine implements OtrEngineHost { private static final String LOGTAG = "xmppService"; private Account account; private OtrPolicy otrPolicy; private KeyPair keyPair; private Context context; public OtrEngine(Context context, Account account) { this.account = account; this.otrPolicy = new OtrPolicyImpl(); this.otrPolicy.setAllowV1(false); this.otrPolicy.setAllowV2(true); this.otrPolicy.setAllowV3(true); this.keyPair = loadKey(account.getKeys()); } private KeyPair loadKey(JSONObject keys) { if (keys == null) { return null; } try { BigInteger x = new BigInteger(keys.getString("otr_x"),16); BigInteger y = new BigInteger(keys.getString("otr_y"),16); BigInteger p = new BigInteger(keys.getString("otr_p"),16); BigInteger q = new BigInteger(keys.getString("otr_q"),16); BigInteger g = new BigInteger(keys.getString("otr_g"),16); KeyFactory keyFactory = KeyFactory.getInstance("DSA"); DSAPublicKeySpec pubKeySpec = new DSAPublicKeySpec(y, p, q, g); DSAPrivateKeySpec privateKeySpec = new DSAPrivateKeySpec(x, p, q, g); PublicKey publicKey = keyFactory.generatePublic(pubKeySpec); PrivateKey privateKey = keyFactory.generatePrivate(privateKeySpec); return new KeyPair(publicKey, privateKey); } catch (JSONException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (NoSuchAlgorithmException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (InvalidKeySpecException e) { // TODO Auto-generated catch block e.printStackTrace(); } return null; } private void saveKey() { PublicKey publicKey = keyPair.getPublic(); PrivateKey privateKey = keyPair.getPrivate(); KeyFactory keyFactory; try { keyFactory = KeyFactory.getInstance("DSA"); DSAPrivateKeySpec privateKeySpec = keyFactory.getKeySpec(privateKey, DSAPrivateKeySpec.class); DSAPublicKeySpec publicKeySpec = keyFactory.getKeySpec(publicKey, DSAPublicKeySpec.class); this.account.setKey("otr_x",privateKeySpec.getX().toString(16)); this.account.setKey("otr_g",privateKeySpec.getG().toString(16)); this.account.setKey("otr_p",privateKeySpec.getP().toString(16)); this.account.setKey("otr_q",privateKeySpec.getQ().toString(16)); this.account.setKey("otr_y",publicKeySpec.getY().toString(16)); } catch (NoSuchAlgorithmException e) { e.printStackTrace(); } catch (InvalidKeySpecException e) { e.printStackTrace(); } catch (JSONException e) { e.printStackTrace(); } } @Override public void askForSecret(SessionID arg0, InstanceTag arg1, String arg2) { // TODO Auto-generated method stub } @Override public void finishedSessionMessage(SessionID arg0, String arg1) throws OtrException { // TODO Auto-generated method stub } @Override public String getFallbackMessage(SessionID arg0) { // TODO Auto-generated method stub return null; } @Override public byte[] getLocalFingerprintRaw(SessionID arg0) { // TODO Auto-generated method stub return null; } @Override public KeyPair getLocalKeyPair(SessionID arg0) throws OtrException { if (this.keyPair==null) { KeyPairGenerator kg; try { kg = KeyPairGenerator.getInstance("DSA"); this.keyPair = kg.genKeyPair(); this.saveKey(); DatabaseBackend.getInstance(context).updateAccount(account); } catch (NoSuchAlgorithmException e) { Log.d(LOGTAG,"error generating key pair "+e.getMessage()); } } return this.keyPair; } @Override public String getReplyForUnreadableMessage(SessionID arg0) { // TODO Auto-generated method stub return null; } @Override public OtrPolicy getSessionPolicy(SessionID arg0) { return otrPolicy; } @Override public void injectMessage(SessionID session, String body) throws OtrException { MessagePacket packet = new MessagePacket(); packet.setFrom(account.getFullJid()); //sender packet.setTo(session.getAccountID()+"/"+session.getUserID()); //reciepient packet.setBody(body); Element privateTag = new Element("private"); privateTag.setAttribute("xmlns","urn:xmpp:carbons:2"); packet.addChild(privateTag); account.getXmppConnection().sendMessagePacket(packet); } @Override public void messageFromAnotherInstanceReceived(SessionID arg0) { // TODO Auto-generated method stub } @Override public void multipleInstancesDetected(SessionID arg0) { // TODO Auto-generated method stub } @Override public void requireEncryptedMessage(SessionID arg0, String arg1) throws OtrException { // TODO Auto-generated method stub } @Override public void showError(SessionID arg0, String arg1) throws OtrException { // TODO Auto-generated method stub } @Override public void smpAborted(SessionID arg0) throws OtrException { // TODO Auto-generated method stub } @Override public void smpError(SessionID arg0, int arg1, boolean arg2) throws OtrException { // TODO Auto-generated method stub } @Override public void unencryptedMessageReceived(SessionID arg0, String arg1) throws OtrException { // TODO Auto-generated method stub } @Override public void unreadableMessageReceived(SessionID arg0) throws OtrException { // TODO Auto-generated method stub } @Override public void unverify(SessionID arg0, String arg1) { // TODO Auto-generated method stub } @Override public void verify(SessionID arg0, String arg1, boolean arg2) { // TODO Auto-generated method stub } }