diff -r fbd3585af53e -r 0ff0059f2ec3 src/net/java/otr4j/OtrKeyManagerImpl.java
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/net/java/otr4j/OtrKeyManagerImpl.java	Sun Dec 05 18:43:51 2010 +0100
@@ -0,0 +1,302 @@
+package net.java.otr4j;
+
+import java.io.BufferedInputStream;
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.FileNotFoundException;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+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.InvalidKeySpecException;
+import java.security.spec.PKCS8EncodedKeySpec;
+import java.security.spec.X509EncodedKeySpec;
+import java.util.List;
+import java.util.Properties;
+import java.util.Vector;
+
+import org.bouncycastle.util.encoders.Base64;
+
+import net.java.otr4j.crypto.OtrCryptoEngineImpl;
+import net.java.otr4j.crypto.OtrCryptoException;
+import net.java.otr4j.session.SessionID;
+
+public class OtrKeyManagerImpl implements OtrKeyManager {
+
+	private OtrKeyManagerStore store;
+
+	public OtrKeyManagerImpl(OtrKeyManagerStore store) {
+		this.store = store;
+	}
+
+	class DefaultPropertiesStore implements OtrKeyManagerStore {
+		private final Properties properties = new Properties();
+		private String filepath;
+
+		public DefaultPropertiesStore(String filepath) throws IOException {
+			if (filepath == null || filepath.length() < 1)
+				throw new IllegalArgumentException();
+			this.filepath = filepath;
+			properties.clear();
+
+			InputStream in = new BufferedInputStream(new FileInputStream(
+					getConfigurationFile()));
+			try {
+				properties.load(in);
+			} finally {
+				in.close();
+			}
+		}
+
+		private File getConfigurationFile() throws IOException {
+			File configFile = new File(filepath);
+			if (!configFile.exists())
+				configFile.createNewFile();
+			return configFile;
+		}
+
+		public void setProperty(String id, boolean value) {
+			properties.setProperty(id, "true");
+			try {
+				this.store();
+			} catch (Exception e) {
+				e.printStackTrace();
+			}
+		}
+
+		private void store() throws FileNotFoundException, IOException {
+			OutputStream out = new FileOutputStream(getConfigurationFile());
+			properties.store(out, null);
+			out.close();
+		}
+
+		public void setProperty(String id, byte[] value) {
+			properties.setProperty(id, new String(Base64.encode(value)));
+			try {
+				this.store();
+			} catch (Exception e) {
+				e.printStackTrace();
+			}
+		}
+
+		public void removeProperty(String id) {
+			properties.remove(id);
+
+		}
+
+		public byte[] getPropertyBytes(String id) {
+			String value = properties.getProperty(id);
+			return Base64.decode(value);
+		}
+
+		public boolean getPropertyBoolean(String id, boolean defaultValue) {
+			try {
+				return Boolean.valueOf(properties.get(id).toString());
+			} catch (Exception e) {
+				return defaultValue;
+			}
+		}
+	}
+
+	public OtrKeyManagerImpl(String filepath) throws IOException {
+		this.store = new DefaultPropertiesStore(filepath);
+	}
+
+	private List<OtrKeyManagerListener> listeners = new Vector<OtrKeyManagerListener>();
+
+	public void addListener(OtrKeyManagerListener l) {
+		synchronized (listeners) {
+			if (!listeners.contains(l))
+				listeners.add(l);
+		}
+	}
+
+	public void removeListener(OtrKeyManagerListener l) {
+		synchronized (listeners) {
+			listeners.remove(l);
+		}
+	}
+
+	public void generateLocalKeyPair(SessionID sessionID) {
+		if (sessionID == null)
+			return;
+
+		String accountID = sessionID.getAccountID();
+		KeyPair keyPair;
+		try {
+			keyPair = KeyPairGenerator.getInstance("DSA").genKeyPair();
+		} catch (NoSuchAlgorithmException e) {
+			e.printStackTrace();
+			return;
+		}
+
+		// Store Public Key.
+		PublicKey pubKey = keyPair.getPublic();
+		X509EncodedKeySpec x509EncodedKeySpec = new X509EncodedKeySpec(pubKey
+				.getEncoded());
+
+		this.store.setProperty(accountID + ".publicKey", x509EncodedKeySpec
+				.getEncoded());
+
+		// Store Private Key.
+		PrivateKey privKey = keyPair.getPrivate();
+		PKCS8EncodedKeySpec pkcs8EncodedKeySpec = new PKCS8EncodedKeySpec(
+				privKey.getEncoded());
+
+		this.store.setProperty(accountID + ".privateKey", pkcs8EncodedKeySpec
+				.getEncoded());
+	}
+
+	public String getLocalFingerprint(SessionID sessionID) {
+		KeyPair keyPair = loadLocalKeyPair(sessionID);
+
+		if (keyPair == null)
+			return null;
+
+		PublicKey pubKey = keyPair.getPublic();
+
+		try {
+			return new OtrCryptoEngineImpl().getFingerprint(pubKey);
+		} catch (OtrCryptoException e) {
+			e.printStackTrace();
+			return null;
+		}
+	}
+
+	public String getRemoteFingerprint(SessionID sessionID) {
+		PublicKey remotePublicKey = loadRemotePublicKey(sessionID);
+		if (remotePublicKey == null)
+			return null;
+		try {
+			return new OtrCryptoEngineImpl().getFingerprint(remotePublicKey);
+		} catch (OtrCryptoException e) {
+			e.printStackTrace();
+			return null;
+		}
+	}
+
+	public boolean isVerified(SessionID sessionID) {
+		if (sessionID == null)
+			return false;
+
+		return this.store.getPropertyBoolean(sessionID.getUserID()
+				+ ".publicKey.verified", false);
+	}
+
+	public KeyPair loadLocalKeyPair(SessionID sessionID) {
+		if (sessionID == null)
+			return null;
+
+		String accountID = sessionID.getAccountID();
+		// Load Private Key.
+		byte[] b64PrivKey = this.store.getPropertyBytes(accountID
+				+ ".privateKey");
+		if (b64PrivKey == null)
+			return null;
+
+		PKCS8EncodedKeySpec privateKeySpec = new PKCS8EncodedKeySpec(b64PrivKey);
+
+		// Load Public Key.
+		byte[] b64PubKey = this.store
+				.getPropertyBytes(accountID + ".publicKey");
+		if (b64PubKey == null)
+			return null;
+
+		X509EncodedKeySpec publicKeySpec = new X509EncodedKeySpec(b64PubKey);
+
+		PublicKey publicKey;
+		PrivateKey privateKey;
+
+		// Generate KeyPair.
+		KeyFactory keyFactory;
+		try {
+			keyFactory = KeyFactory.getInstance("DSA");
+			publicKey = keyFactory.generatePublic(publicKeySpec);
+			privateKey = keyFactory.generatePrivate(privateKeySpec);
+		} catch (NoSuchAlgorithmException e) {
+			e.printStackTrace();
+			return null;
+		} catch (InvalidKeySpecException e) {
+			e.printStackTrace();
+			return null;
+		}
+
+		return new KeyPair(publicKey, privateKey);
+	}
+
+	public PublicKey loadRemotePublicKey(SessionID sessionID) {
+		if (sessionID == null)
+			return null;
+
+		String userID = sessionID.getUserID();
+
+		byte[] b64PubKey = this.store.getPropertyBytes(userID + ".publicKey");
+		if (b64PubKey == null)
+			return null;
+
+		X509EncodedKeySpec publicKeySpec = new X509EncodedKeySpec(b64PubKey);
+
+		// Generate KeyPair.
+		KeyFactory keyFactory;
+		try {
+			keyFactory = KeyFactory.getInstance("DSA");
+			return keyFactory.generatePublic(publicKeySpec);
+		} catch (NoSuchAlgorithmException e) {
+			e.printStackTrace();
+			return null;
+		} catch (InvalidKeySpecException e) {
+			e.printStackTrace();
+			return null;
+		}
+	}
+
+	public void savePublicKey(SessionID sessionID, PublicKey pubKey) {
+		if (sessionID == null)
+			return;
+
+		X509EncodedKeySpec x509EncodedKeySpec = new X509EncodedKeySpec(pubKey
+				.getEncoded());
+
+		String userID = sessionID.getUserID();
+		this.store.setProperty(userID + ".publicKey", x509EncodedKeySpec
+				.getEncoded());
+
+		this.store.removeProperty(userID + ".publicKey.verified");
+	}
+
+	public void unverify(SessionID sessionID) {
+		if (sessionID == null)
+			return;
+
+		if (!isVerified(sessionID))
+			return;
+
+		this.store
+				.removeProperty(sessionID.getUserID() + ".publicKey.verified");
+
+		for (OtrKeyManagerListener l : listeners)
+			l.verificationStatusChanged(sessionID);
+
+	}
+
+	public void verify(SessionID sessionID) {
+		if (sessionID == null)
+			return;
+
+		if (this.isVerified(sessionID))
+			return;
+
+		this.store.setProperty(sessionID.getUserID() + ".publicKey.verified",
+				true);
+
+		for (OtrKeyManagerListener l : listeners)
+			l.verificationStatusChanged(sessionID);
+	}
+
+}