Add purge axolotl key option

Can now long-press a key to permanently purge it.

src/main/java/eu/siacs/conversations/crypto/axolotl/AxolotlService.java

@@ -100,7 +100,8 @@ public class AxolotlService {
 		public enum Trust {
 			UNDECIDED, // 0
 			TRUSTED,
-			UNTRUSTED;
+			UNTRUSTED,
+			COMPROMISED;
 
 			public String toString() {
 				switch(this){
@@ -514,8 +515,16 @@ public class AxolotlService {
 			return fingerprint;
 		}
 
+		private SQLiteAxolotlStore.Trust getTrust() {
+			return sqLiteAxolotlStore.getFingerprintTrust(fingerprint);
+		}
+
+		@Nullable
 		public byte[] processReceiving(XmppAxolotlMessage.XmppAxolotlMessageHeader incomingHeader) {
 			byte[] plaintext = null;
+			switch (getTrust()) {
+				case UNDECIDED:
+				case TRUSTED:
 					try {
 						try {
 							PreKeyWhisperMessage message = new PreKeyWhisperMessage(incomingHeader.getContents());
@@ -540,15 +549,30 @@ public class AxolotlService {
 					} catch (LegacyMessageException | InvalidMessageException | DuplicateMessageException | NoSessionException  e) {
 						Log.w(Config.LOGTAG, AxolotlService.getLogprefix(account)+"Error decrypting axolotl header, "+e.getClass().getName()+": " + e.getMessage());
 					}
+
+					break;
+
+				case COMPROMISED:
+				case UNTRUSTED:
+				default:
+					// ignore
+					break;
+			}
 			return plaintext;
 		}
 
-		public XmppAxolotlMessage.XmppAxolotlMessageHeader processSending(byte[] outgoingMessage) {
+		@Nullable
+		public XmppAxolotlMessage.XmppAxolotlMessageHeader processSending(@NonNull byte[] outgoingMessage) {
+			SQLiteAxolotlStore.Trust trust = getTrust();
+			if (trust == SQLiteAxolotlStore.Trust.TRUSTED) {
 				CiphertextMessage ciphertextMessage = cipher.encrypt(outgoingMessage);
 				XmppAxolotlMessage.XmppAxolotlMessageHeader header =
 						new XmppAxolotlMessage.XmppAxolotlMessageHeader(remoteAddress.getDeviceId(),
 								ciphertextMessage.serialize());
 				return header;
+			} else {
+				return null;
+			}
 		}
 	}
 
@@ -742,6 +766,10 @@ public class AxolotlService {
 		});
 	}
 
+	public void purgeKey(IdentityKey identityKey) {
+		axolotlStore.setFingerprintTrust(identityKey.getFingerprint().replaceAll("\\s",""), SQLiteAxolotlStore.Trust.COMPROMISED);
+	}
+
 	public void publishOwnDeviceIdIfNeeded() {
 		IqPacket packet = mXmppConnectionService.getIqGenerator().retrieveDeviceIds(account.getJid().toBareJid());
 		mXmppConnectionService.sendIqPacket(account, packet, new OnIqPacketReceived() {

src/main/java/eu/siacs/conversations/crypto/axolotl/XmppAxolotlMessage.java

@@ -1,5 +1,6 @@
 package eu.siacs.conversations.crypto.axolotl;
 
+import android.support.annotation.Nullable;
 import android.util.Base64;
 
 import java.security.InvalidAlgorithmParameterException;
@@ -145,9 +146,11 @@ public class XmppAxolotlMessage {
 		return headers;
 	}
 
-	public void addHeader(XmppAxolotlMessageHeader header) {
+	public void addHeader(@Nullable XmppAxolotlMessageHeader header) {
+		if (header != null) {
 			headers.add(header);
 		}
+	}
 
 	public byte[] getInnerKey(){
 		return innerKey;

src/main/java/eu/siacs/conversations/ui/ContactDetailsActivity.java

@@ -384,8 +384,7 @@ public class ContactDetailsActivity extends XmppActivity implements OnAccountUpd
 		}
 		for(final IdentityKey identityKey : xmppConnectionService.databaseBackend.loadIdentityKeys(
 				contact.getAccount(), contact.getJid().toBareJid().toString())) {
-			hasKeys = true;
-			addFingerprintRow(keys, contact.getAccount(), identityKey);
+			hasKeys |= addFingerprintRow(keys, contact.getAccount(), identityKey);
 		}
 		if (contact.getPgpKeyId() != 0) {
 			hasKeys = true;

src/main/java/eu/siacs/conversations/ui/EditAccountActivity.java

@@ -566,8 +566,7 @@ public class EditAccountActivity extends XmppActivity implements OnAccountUpdate
 				if(ownKey.equals(identityKey)) {
 					continue;
 				}
-				hasKeys = true;
-				addFingerprintRow(keys, mAccount, identityKey);
+				hasKeys |= addFingerprintRow(keys, mAccount, identityKey);
 			}
 			if (hasKeys) {
 				keysCard.setVisibility(View.VISIBLE);

src/main/java/eu/siacs/conversations/ui/XmppActivity.java

@@ -601,11 +601,11 @@ public abstract class XmppActivity extends Activity {
 		builder.create().show();
 	}
 
-	protected void addFingerprintRow(LinearLayout keys, final Account account, IdentityKey identityKey) {
+	protected boolean addFingerprintRow(LinearLayout keys, final Account account, IdentityKey identityKey) {
 		final String fingerprint = identityKey.getFingerprint().replaceAll("\\s", "");
 		final AxolotlService.SQLiteAxolotlStore.Trust trust = account.getAxolotlService()
 				.getFingerprintTrust(fingerprint);
-		addFingerprintRowWithListeners(keys, account, identityKey, trust, true,
+		return addFingerprintRowWithListeners(keys, account, identityKey, trust, true,
 				new CompoundButton.OnCheckedChangeListener() {
 					@Override
 					public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
@@ -633,13 +633,16 @@ public abstract class XmppActivity extends Activity {
 		);
 	}
 
-	protected void addFingerprintRowWithListeners(LinearLayout keys, final Account account,
-	                                              IdentityKey identityKey,
+	protected boolean addFingerprintRowWithListeners(LinearLayout keys, final Account account,
+	                                              final IdentityKey identityKey,
 	                                              AxolotlService.SQLiteAxolotlStore.Trust trust,
 	                                              boolean showTag,
 	                                              CompoundButton.OnCheckedChangeListener
 			                                             onCheckedChangeListener,
 	                                              View.OnClickListener onClickListener) {
+		if (trust == AxolotlService.SQLiteAxolotlStore.Trust.COMPROMISED) {
+			return false;
+		}
 		View view = getLayoutInflater().inflate(R.layout.contact_key, keys, false);
 		TextView key = (TextView) view.findViewById(R.id.key);
 		TextView keyType = (TextView) view.findViewById(R.id.key_type);
@@ -647,6 +650,13 @@ public abstract class XmppActivity extends Activity {
 		trustToggle.setVisibility(View.VISIBLE);
 		trustToggle.setOnCheckedChangeListener(onCheckedChangeListener);
 		trustToggle.setOnClickListener(onClickListener);
+		view.setOnLongClickListener(new View.OnLongClickListener() {
+			@Override
+			public boolean onLongClick(View v) {
+				showPurgeKeyDialog(account, identityKey);
+				return true;
+			}
+		});
 
 		switch (trust) {
 			case UNTRUSTED:
@@ -668,7 +678,26 @@ public abstract class XmppActivity extends Activity {
 
 		key.setText(CryptoHelper.prettifyFingerprint(identityKey.getFingerprint()));
 		keys.addView(view);
+		return true;
+	}
 
+	public void showPurgeKeyDialog(final Account account, final IdentityKey identityKey) {
+		Builder builder = new Builder(this);
+		builder.setTitle(getString(R.string.purge_key));
+		builder.setIconAttribute(android.R.attr.alertDialogIcon);
+		builder.setMessage(getString(R.string.purge_key_desc_part1)
+				+ "\n\n" + CryptoHelper.prettifyFingerprint(identityKey.getFingerprint())
+				+ "\n\n" + getString(R.string.purge_key_desc_part2));
+		builder.setNegativeButton(getString(R.string.cancel), null);
+		builder.setPositiveButton(getString(R.string.accept),
+				new DialogInterface.OnClickListener() {
+					@Override
+					public void onClick(DialogInterface dialog, int which) {
+						account.getAxolotlService().purgeKey(identityKey);
+						refreshUi();
+					}
+				});
+		builder.create().show();
 	}
 
 	public void selectPresence(final Conversation conversation,

src/main/res/values/strings.xml

@@ -393,6 +393,9 @@
 	<string name="wipe_axolotl_pep">Wipe other devices from PEP</string>
 	<string name="clear_other_devices">Clear devices</string>
 	<string name="clear_other_devices_desc">Are you sure you want to clear all other devices from the axolotl announcement? The next time your devices connect, they will reannounce themselves, but they might not receive messages sent in the meantime.</string>
+	<string name="purge_key">Purge key</string>
+	<string name="purge_key_desc_part1">Are you sure you want to purge this key?</string>
+	<string name="purge_key_desc_part2">It will irreversibly be considered compromised, and you can never build a session with it again.</string>
 	<string name="fetching_history_from_server">Fetching history from server</string>
 	<string name="no_more_history_on_server">No more history on server</string>
 	<string name="updating">Updating…</string>