basic otr support

1 files changed, 229 insertions, 0 deletions

diff --git a/src/de/gultsch/chat/crypto/OtrEngine.java b/src/de/gultsch/chat/crypto/OtrEngine.java
new file mode 100644
index 00000000..d994f0f9
--- /dev/null
+++ b/src/de/gultsch/chat/crypto/OtrEngine.java
@@ -0,0 +1,229 @@
+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
+
+	}
+
+}