Use XSalsa20-Poly1305 instead of AES-GCM for transport encryption and password storage.

This patch integrates @str4d's new authenticated cipher implementation. It depends on !18 (merged).

briar-android/src/org/briarproject/android/invitation/AddContactActivity.java

@@ -55,12 +55,12 @@ implements InvitationListener {
private boolean localCompared = false, remoteCompared = false;
private boolean localMatched = false, remoteMatched = false;
private String contactName = null;
-	private boolean bluetoothWasEnabled = false;
// Fields that are accessed from background threads must be volatile
@Inject private volatile DatabaseComponent db;
@Inject private volatile IdentityManager identityManager;
-	private volatile boolean leaveBluetoothEnabled = true;
+	private volatile boolean bluetoothWasEnabled = false;
+	private volatile boolean leaveBluetoothEnabled = false;
@Override
public void onCreate(Bundle state) {
@@ -173,7 +173,8 @@ implements InvitationListener {
long duration = System.currentTimeMillis() - now;
if (LOG.isLoggable(INFO))
LOG.info("Loading setting took " + duration + " ms");
-					leaveBluetoothEnabled = c.getBoolean("enable", false);
+					leaveBluetoothEnabled = bluetoothWasEnabled
+							|| c.getBoolean("enable", false);
} catch (DbException e) {
if (LOG.isLoggable(WARNING))
LOG.log(WARNING, e.toString(), e);
@@ -328,7 +329,7 @@ implements InvitationListener {
}
public void disableBluetooth() {
-		if (!bluetoothWasEnabled && !leaveBluetoothEnabled) {
+		if (!leaveBluetoothEnabled) {
if (LOG.isLoggable(INFO)) LOG.info("Turning off Bluetooth again");
BluetoothAdapter adapter = BluetoothAdapter.getDefaultAdapter();