refactor: Add secretstoragekeycontent

lib/encryption/cross_signing.dart

@@ -24,15 +24,12 @@ import 'package:olm/olm.dart' as olm;
 import '../famedlysdk.dart';
 import 'encryption.dart';
 
-const SELF_SIGNING_KEY = EventTypes.CrossSigningSelfSigning;
-const USER_SIGNING_KEY = EventTypes.CrossSigningUserSigning;
-const MASTER_KEY = 'm.cross_signing.master';
-
 class CrossSigning {
   final Encryption encryption;
   Client get client => encryption.client;
   CrossSigning(this.encryption) {
-    encryption.ssss.setValidator(SELF_SIGNING_KEY, (String secret) async {
+    encryption.ssss.setValidator(EventTypes.CrossSigningSelfSigning,
+        (String secret) async {
       final keyObj = olm.PkSigning();
       try {
         return keyObj.init_with_seed(base64.decode(secret)) ==
@@ -43,7 +40,8 @@ class CrossSigning {
         keyObj.free();
       }
     });
-    encryption.ssss.setValidator(USER_SIGNING_KEY, (String secret) async {
+    encryption.ssss.setValidator(EventTypes.CrossSigningUserSigning,
+        (String secret) async {
       final keyObj = olm.PkSigning();
       try {
         return keyObj.init_with_seed(base64.decode(secret)) ==
@@ -57,23 +55,27 @@ class CrossSigning {
   }
 
   bool get enabled =>
-      client.accountData[SELF_SIGNING_KEY] != null &&
+      client.accountData[EventTypes.CrossSigningSelfSigning] != null &&
-      client.accountData[USER_SIGNING_KEY] != null &&
+      client.accountData[EventTypes.CrossSigningUserSigning] != null &&
-      client.accountData[MASTER_KEY] != null;
+      client.accountData[EventTypes.CrossSigningMasterKey] != null;
 
   Future<bool> isCached() async {
     if (!enabled) {
       return false;
     }
-    return (await encryption.ssss.getCached(SELF_SIGNING_KEY)) != null &&
+    return (await encryption.ssss
-        (await encryption.ssss.getCached(USER_SIGNING_KEY)) != null;
+                .getCached(EventTypes.CrossSigningSelfSigning)) !=
+            null &&
+        (await encryption.ssss.getCached(EventTypes.CrossSigningUserSigning)) !=
+            null;
   }
 
   Future<void> selfSign({String passphrase, String recoveryKey}) async {
-    final handle = encryption.ssss.open(MASTER_KEY);
+    final handle = encryption.ssss.open(EventTypes.CrossSigningMasterKey);
     await handle.unlock(passphrase: passphrase, recoveryKey: recoveryKey);
     await handle.maybeCacheAll();
-    final masterPrivateKey = base64.decode(await handle.getStored(MASTER_KEY));
+    final masterPrivateKey =
+        base64.decode(await handle.getStored(EventTypes.CrossSigningMasterKey));
     final keyObj = olm.PkSigning();
     String masterPubkey;
     try {
@@ -85,11 +87,11 @@ class CrossSigning {
         !client.userDeviceKeys.containsKey(client.userID) ||
         !client.userDeviceKeys[client.userID].deviceKeys
             .containsKey(client.deviceID)) {
-      throw 'Master or user keys not found';
+      throw Exception('Master or user keys not found');
     }
     final masterKey = client.userDeviceKeys[client.userID].masterKey;
     if (masterKey == null || masterKey.ed25519Key != masterPubkey) {
-      throw 'Master pubkey key doesn\'t match';
+      throw Exception('Master pubkey key doesn\'t match');
     }
     // master key is valid, set it to verified
     await masterKey.setVerified(true, false);
@@ -146,8 +148,9 @@ class CrossSigning {
           // we don't care about signing other cross-signing keys
         } else {
           // okay, we'll sign a device key with our self signing key
-          selfSigningKey ??= base64
+          selfSigningKey ??= base64.decode(await encryption.ssss
-              .decode(await encryption.ssss.getCached(SELF_SIGNING_KEY) ?? '');
+                  .getCached(EventTypes.CrossSigningSelfSigning) ??
+              '');
           if (selfSigningKey.isNotEmpty) {
             final signature = _sign(key.signingContent, selfSigningKey);
             addSignature(key,
@@ -156,8 +159,9 @@ class CrossSigning {
         }
       } else if (key is CrossSigningKey && key.usage.contains('master')) {
         // we are signing someone elses master key
-        userSigningKey ??= base64
+        userSigningKey ??= base64.decode(await encryption.ssss
-            .decode(await encryption.ssss.getCached(USER_SIGNING_KEY) ?? '');
+                .getCached(EventTypes.CrossSigningUserSigning) ??
+            '');
         if (userSigningKey.isNotEmpty) {
           final signature = _sign(key.signingContent, userSigningKey);
           addSignature(key, client.userDeviceKeys[client.userID].userSigningKey,

lib/encryption/encryption.dart

@@ -46,6 +46,13 @@ class Encryption {
   String get fingerprintKey => olmManager.fingerprintKey;
   String get identityKey => olmManager.identityKey;
 
+  /// ToDeviceEventDecryptionError erros are coming here.
+  final StreamController<ToDeviceEventDecryptionError>
+      onToDeviceEventDecryptionError = StreamController.broadcast();
+
+  /// All other erros are coming here.
+  final StreamController<SdkError> onError = StreamController.broadcast();
+
   KeyManager keyManager;
   OlmManager olmManager;
   KeyVerificationManager keyVerificationManager;
@@ -132,7 +139,21 @@ class Encryption {
   }
 
   Future<ToDeviceEvent> decryptToDeviceEvent(ToDeviceEvent event) async {
-    return await olmManager.decryptToDeviceEvent(event);
+    try {
+      return await olmManager.decryptToDeviceEvent(event);
+    } catch (e, s) {
+      Logs.error(
+          '[LibOlm] Could not decrypt to device event from ${event.sender} with content: ${event.content}\n${e.toString()}',
+          s);
+      onToDeviceEventDecryptionError.add(
+        ToDeviceEventDecryptionError(
+          exception: e is Exception ? e : Exception(e),
+          stackTrace: s,
+          toDeviceEvent: event,
+        ),
+      );
+      return event;
+    }
   }
 
   Event decryptRoomEventSync(String roomId, Event event) {

lib/encryption/ssss.dart

@@ -53,6 +53,9 @@ Map<String, dynamic> _deepcopy(Map<String, dynamic> data) {
   return json.decode(json.encode(data));
 }
 
+/// SSSS: **S**ecure **S**ecret **S**torage and **S**haring
+/// Read more about SSSS at:
+/// https://matrix.org/docs/guides/implementing-more-advanced-e-2-ee-features-such-as-cross-signing#3-implementing-ssss
 class SSSS {
   final Encryption encryption;
   Client get client => encryption.client;
@@ -113,7 +116,7 @@ class SSSS {
         .encode(Hmac(sha256, keys.hmacKey).convert(cipher).bytes)
         .replaceAll(RegExp(r'=+$'), '');
     if (hmac != data.mac.replaceAll(RegExp(r'=+$'), '')) {
-      throw 'Bad MAC';
+      throw Exception('Bad MAC');
     }
     final decipher = AES(Key(keys.aesKey), mode: AESMode.ctr, padding: null)
         .decrypt(Encrypted(cipher), iv: IV(base64.decode(data.iv)));
@@ -128,26 +131,26 @@ class SSSS {
       parity ^= b;
     }
     if (parity != 0) {
-      throw 'Incorrect parity';
+      throw Exception('Incorrect parity');
     }
 
     for (var i = 0; i < OLM_RECOVERY_KEY_PREFIX.length; i++) {
       if (result[i] != OLM_RECOVERY_KEY_PREFIX[i]) {
-        throw 'Incorrect prefix';
+        throw Exception('Incorrect prefix');
       }
     }
 
     if (result.length != OLM_RECOVERY_KEY_PREFIX.length + SSSS_KEY_LENGTH + 1) {
-      throw 'Incorrect length';
+      throw Exception('Incorrect length');
     }
 
     return Uint8List.fromList(result.sublist(OLM_RECOVERY_KEY_PREFIX.length,
         OLM_RECOVERY_KEY_PREFIX.length + SSSS_KEY_LENGTH));
   }
 
-  static Uint8List keyFromPassphrase(String passphrase, _PassphraseInfo info) {
+  static Uint8List keyFromPassphrase(String passphrase, PassphraseInfo info) {
     if (info.algorithm != AlgorithmTypes.pbkdf2) {
-      throw 'Unknown algorithm';
+      throw Exception('Unknown algorithm');
     }
     final generator = PBKDF2(hashAlgorithm: sha512);
     return Uint8List.fromList(generator.generateKey(passphrase, info.salt,
@@ -162,55 +165,45 @@ class SSSS {
     _cacheCallbacks[type] = callback;
   }
 
-  String get defaultKeyId {
+  String get defaultKeyId => client
-    final keyData = client.accountData[EventTypes.SecretStorageDefaultKey];
+      .accountData[EventTypes.SecretStorageDefaultKey]
-    if (keyData == null || !(keyData.content['key'] is String)) {
+      ?.parsedSecretStorageDefaultKeyContent
-      return null;
+      ?.key;
-    }
-    return keyData.content['key'];
-  }
 
   Future<void> setDefaultKeyId(String keyId) async {
     await client.setAccountData(
-        client.userID, EventTypes.SecretStorageDefaultKey, <String, dynamic>{
+      client.userID,
-      'key': keyId,
+      EventTypes.SecretStorageDefaultKey,
-    });
+      (SecretStorageDefaultKeyContent()..key = keyId).toJson(),
+    );
   }
 
-  BasicEvent getKey(String keyId) {
+  SecretStorageKeyContent getKey(String keyId) {
-    return client.accountData[EventTypes.secretStorageKey(keyId)];
+    return client.accountData[EventTypes.secretStorageKey(keyId)]
+        ?.parsedSecretStorageKeyContent;
   }
 
-  bool isKeyValid(String keyId) {
+  bool isKeyValid(String keyId) =>
-    final keyData = getKey(keyId);
+      getKey(keyId)?.algorithm == AlgorithmTypes.secretStorageV1AesHmcSha2;
-    if (keyData == null) {
-      return false;
-    }
-    return keyData.content['algorithm'] ==
-        AlgorithmTypes.secretStorageV1AesHmcSha2;
-  }
 
+  /// Creates a new secret storage key, optional encrypts it with [passphrase]
+  /// and stores it in the user's [accountData].
   Future<OpenSSSS> createKey([String passphrase]) async {
     Uint8List privateKey;
-    final content = <String, dynamic>{};
+    final content = SecretStorageKeyContent();
     if (passphrase != null) {
       // we need to derive the key off of the passphrase
-      content['passphrase'] = <String, dynamic>{};
+      content.passphrase = PassphraseInfo();
-      content['passphrase']['algorithm'] = AlgorithmTypes.pbkdf2;
+      content.passphrase.algorithm = AlgorithmTypes.pbkdf2;
-      content['passphrase']['salt'] = base64
+      content.passphrase.salt = base64
           .encode(SecureRandom(PBKDF2_SALT_LENGTH).bytes); // generate salt
-      content['passphrase']['iterations'] = PBKDF2_DEFAULT_ITERATIONS;
+      content.passphrase.iterations = PBKDF2_DEFAULT_ITERATIONS;
-      content['passphrase']['bits'] = SSSS_KEY_LENGTH * 8;
+      content.passphrase.bits = SSSS_KEY_LENGTH * 8;
       privateKey = await runInBackground(
           _keyFromPassphrase,
           _KeyFromPassphraseArgs(
             passphrase: passphrase,
-            info: _PassphraseInfo(
+            info: content.passphrase,
-              algorithm: content['passphrase']['algorithm'],
-              salt: content['passphrase']['salt'],
-              iterations: content['passphrase']['iterations'],
-              bits: content['passphrase']['bits'],
-            ),
           ));
     } else {
       // we need to just generate a new key from scratch
@@ -218,9 +211,9 @@ class SSSS {
     }
     // now that we have the private key, let's create the iv and mac
     final encrypted = encryptAes(ZERO_STR, privateKey, '');
-    content['iv'] = encrypted.iv;
+    content.iv = encrypted.iv;
-    content['mac'] = encrypted.mac;
+    content.mac = encrypted.mac;
-    content['algorithm'] = AlgorithmTypes.secretStorageV1AesHmcSha2;
+    content.algorithm = AlgorithmTypes.secretStorageV1AesHmcSha2;
 
     const KEYID_BYTE_LENGTH = 24;
 
@@ -235,7 +228,8 @@ class SSSS {
     final waitForAccountData = client.onSync.stream.firstWhere((syncUpdate) =>
         syncUpdate.accountData
             .any((accountData) => accountData.type == accountDataType));
-    await client.setAccountData(client.userID, accountDataType, content);
+    await client.setAccountData(
+        client.userID, accountDataType, content.toJson());
     await waitForAccountData;
 
     final key = open(keyId);
@@ -243,19 +237,18 @@ class SSSS {
     return key;
   }
 
-  bool checkKey(Uint8List key, BasicEvent keyData) {
+  bool checkKey(Uint8List key, SecretStorageKeyContent info) {
-    final info = keyData.content;
+    if (info.algorithm == AlgorithmTypes.secretStorageV1AesHmcSha2) {
-    if (info['algorithm'] == AlgorithmTypes.secretStorageV1AesHmcSha2) {
+      if ((info.mac is String) && (info.iv is String)) {
-      if ((info['mac'] is String) && (info['iv'] is String)) {
+        final encrypted = encryptAes(ZERO_STR, key, '', info.iv);
-        final encrypted = encryptAes(ZERO_STR, key, '', info['iv']);
+        return info.mac.replaceAll(RegExp(r'=+$'), '') ==
-        return info['mac'].replaceAll(RegExp(r'=+$'), '') ==
             encrypted.mac.replaceAll(RegExp(r'=+$'), '');
       } else {
         // no real information about the key, assume it is valid
         return true;
       }
     } else {
-      throw 'Unknown Algorithm';
+      throw Exception('Unknown Algorithm');
     }
   }
 
@@ -287,13 +280,13 @@ class SSSS {
   Future<String> getStored(String type, String keyId, Uint8List key) async {
     final secretInfo = client.accountData[type];
     if (secretInfo == null) {
-      throw 'Not found';
+      throw Exception('Not found');
     }
     if (!(secretInfo.content['encrypted'] is Map)) {
-      throw 'Content is not encrypted';
+      throw Exception('Content is not encrypted');
     }
     if (!(secretInfo.content['encrypted'][keyId] is Map)) {
-      throw 'Wrong / unknown key';
+      throw Exception('Wrong / unknown key');
     }
     final enc = secretInfo.content['encrypted'][keyId];
     final encryptInfo = _Encrypted(
@@ -345,7 +338,7 @@ class SSSS {
   Future<void> validateAndStripOtherKeys(
       String type, String secret, String keyId, Uint8List key) async {
     if (await getStored(type, keyId, key) != secret) {
-      throw 'Secrets do not match up!';
+      throw Exception('Secrets do not match up!');
     }
     // now remove all other keys
     final content = _deepcopy(client.accountData[type].content);
@@ -354,7 +347,7 @@ class SSSS {
     content['encrypted'].removeWhere((k, v) => otherKeys.contains(k));
     // yes, we are paranoid...
     if (await getStored(type, keyId, key) != secret) {
-      throw 'Secrets do not match up!';
+      throw Exception('Secrets do not match up!');
     }
     // store the thing in your account data
     await client.setAccountData(client.userID, type, content);
@@ -561,15 +554,15 @@ class SSSS {
   OpenSSSS open([String identifier]) {
     identifier ??= defaultKeyId;
     if (identifier == null) {
-      throw 'Dont know what to open';
+      throw Exception('Dont know what to open');
     }
     final keyToOpen = keyIdFromType(identifier) ?? identifier;
     if (keyToOpen == null) {
-      throw 'No key found to open';
+      throw Exception('No key found to open');
     }
     final key = getKey(keyToOpen);
     if (key == null) {
-      throw 'Unknown key to open';
+      throw Exception('Unknown key to open');
     }
     return OpenSSSS(ssss: this, keyId: keyToOpen, keyData: key);
   }
@@ -600,19 +593,10 @@ class _DerivedKeys {
   _DerivedKeys({this.aesKey, this.hmacKey});
 }
 
-class _PassphraseInfo {
-  final String algorithm;
-  final String salt;
-  final int iterations;
-  final int bits;
-
-  _PassphraseInfo({this.algorithm, this.salt, this.iterations, this.bits});
-}
-
 class OpenSSSS {
   final SSSS ssss;
   final String keyId;
-  final BasicEvent keyData;
+  final SecretStorageKeyContent keyData;
   OpenSSSS({this.ssss, this.keyId, this.keyData});
   Uint8List privateKey;
 
@@ -632,28 +616,23 @@ class OpenSSSS {
           _keyFromPassphrase,
           _KeyFromPassphraseArgs(
             passphrase: passphrase,
-            info: _PassphraseInfo(
+            info: keyData.passphrase,
-              algorithm: keyData.content['passphrase']['algorithm'],
-              salt: keyData.content['passphrase']['salt'],
-              iterations: keyData.content['passphrase']['iterations'],
-              bits: keyData.content['passphrase']['bits'],
-            ),
           ));
     } else if (recoveryKey != null) {
       privateKey = SSSS.decodeRecoveryKey(recoveryKey);
     } else {
-      throw 'Nothing specified';
+      throw Exception('Nothing specified');
     }
     // verify the validity of the key
     if (!ssss.checkKey(privateKey, keyData)) {
       privateKey = null;
-      throw 'Inalid key';
+      throw Exception('Inalid key');
     }
   }
 
   void setPrivateKey(Uint8List key) {
     if (!ssss.checkKey(key, keyData)) {
-      throw 'Invalid key';
+      throw Exception('Invalid key');
     }
     privateKey = key;
   }
@@ -677,7 +656,7 @@ class OpenSSSS {
 
 class _KeyFromPassphraseArgs {
   final String passphrase;
-  final _PassphraseInfo info;
+  final PassphraseInfo info;
   _KeyFromPassphraseArgs({this.passphrase, this.info});
 }
 

lib/encryption/utils/bootstrap.dart

@@ -24,7 +24,6 @@ import 'package:olm/olm.dart' as olm;
 
 import '../encryption.dart';
 import '../ssss.dart';
-import '../cross_signing.dart';
 import '../key_manager.dart';
 import '../../famedlysdk.dart';
 import '../../matrix_api/utils/logs.dart';
@@ -45,6 +44,7 @@ enum BootstrapState {
   done, // done
 }
 
+/// Bootstrapping SSSS and cross-signing
 class Bootstrap {
   final Encryption encryption;
   Client get client => encryption.client;
@@ -162,7 +162,7 @@ class Bootstrap {
 
   void wipeSsss(bool wipe) {
     if (state != BootstrapState.askWipeSsss) {
-      throw Exception('Wrong State');
+      throw BootstrapBadStateException('Wrong State');
     }
     if (wipe) {
       state = BootstrapState.askNewSsss;
@@ -178,7 +178,7 @@ class Bootstrap {
 
   void useExistingSsss(bool use) {
     if (state != BootstrapState.askUseExistingSsss) {
-      throw Exception('Wrong State');
+      throw BootstrapBadStateException('Wrong State');
     }
     if (use) {
       newSsssKey = encryption.ssss.open(encryption.ssss.defaultKeyId);
@@ -192,7 +192,7 @@ class Bootstrap {
 
   void ignoreBadSecrets(bool ignore) {
     if (state != BootstrapState.askBadSsss) {
-      throw Exception('Wrong State');
+      throw BootstrapBadStateException('Wrong State');
     }
     if (ignore) {
       migrateOldSsss();
@@ -221,14 +221,14 @@ class Bootstrap {
 
   void unlockedSsss() {
     if (state != BootstrapState.askUnlockSsss) {
-      throw Exception('Wrong State');
+      throw BootstrapBadStateException('Wrong State');
     }
     state = BootstrapState.askNewSsss;
   }
 
   Future<void> newSsss([String passphrase]) async {
     if (state != BootstrapState.askNewSsss) {
-      throw Exception('Wrong State');
+      throw BootstrapBadStateException('Wrong State');
     }
     state = BootstrapState.loading;
     try {
@@ -285,10 +285,10 @@ class Bootstrap {
 
   void openExistingSsss() {
     if (state != BootstrapState.openExistingSsss) {
-      throw 'Bad State';
+      throw BootstrapBadStateException();
     }
     if (!newSsssKey.isUnlocked) {
-      throw 'Key not unlocked';
+      throw BootstrapBadStateException('Key not unlocked');
     }
     checkCrossSigning();
   }
@@ -306,7 +306,7 @@ class Bootstrap {
 
   void wipeCrossSigning(bool wipe) {
     if (state != BootstrapState.askWipeCrossSigning) {
-      throw 'Bad State';
+      throw BootstrapBadStateException();
     }
     if (wipe) {
       state = BootstrapState.askSetupCrossSigning;
@@ -320,7 +320,7 @@ class Bootstrap {
       bool setupSelfSigningKey = false,
       bool setupUserSigningKey = false}) async {
     if (state != BootstrapState.askSetupCrossSigning) {
-      throw 'Bad State';
+      throw BootstrapBadStateException();
     }
     if (!setupMasterKey && !setupSelfSigningKey && !setupUserSigningKey) {
       checkOnlineKeyBackup();
@@ -345,16 +345,17 @@ class Bootstrap {
           },
         };
         masterKey = MatrixCrossSigningKey.fromJson(json);
-        secretsToStore[MASTER_KEY] = base64.encode(masterSigningKey);
+        secretsToStore[EventTypes.CrossSigningMasterKey] =
+            base64.encode(masterSigningKey);
       } finally {
         master.free();
       }
     } else {
-      masterSigningKey =
+      masterSigningKey = base64.decode(
-          base64.decode(await newSsssKey.getStored(MASTER_KEY) ?? '');
+          await newSsssKey.getStored(EventTypes.CrossSigningMasterKey) ?? '');
       if (masterSigningKey == null || masterSigningKey.isEmpty) {
         // no master signing key :(
-        throw 'No master key';
+        throw BootstrapBadStateException('No master key');
       }
       final master = olm.PkSigning();
       try {
@@ -391,7 +392,8 @@ class Bootstrap {
           },
         };
         selfSigningKey = MatrixCrossSigningKey.fromJson(json);
-        secretsToStore[SELF_SIGNING_KEY] = base64.encode(selfSigningPriv);
+        secretsToStore[EventTypes.CrossSigningSelfSigning] =
+            base64.encode(selfSigningPriv);
       } finally {
         selfSigning.free();
       }
@@ -415,7 +417,8 @@ class Bootstrap {
           },
         };
         userSigningKey = MatrixCrossSigningKey.fromJson(json);
-        secretsToStore[USER_SIGNING_KEY] = base64.encode(userSigningPriv);
+        secretsToStore[EventTypes.CrossSigningUserSigning] =
+            base64.encode(userSigningPriv);
       } finally {
         userSigning.free();
       }
@@ -451,7 +454,8 @@ class Bootstrap {
       if (masterKey != null) {
         if (client.userDeviceKeys[client.userID].masterKey.ed25519Key !=
             masterKey.publicKey) {
-          throw 'ERROR: New master key does not match up!';
+          throw BootstrapBadStateException(
+              'ERROR: New master key does not match up!');
         }
         await client.userDeviceKeys[client.userID].masterKey
             .setVerified(true, false);
@@ -484,7 +488,7 @@ class Bootstrap {
 
   void wipeOnlineKeyBackup(bool wipe) {
     if (state != BootstrapState.askWipeOnlineKeyBackup) {
-      throw 'Bad State';
+      throw BootstrapBadStateException();
     }
     if (wipe) {
       state = BootstrapState.askSetupOnlineKeyBackup;
@@ -495,7 +499,7 @@ class Bootstrap {
 
   Future<void> askSetupOnlineKeyBackup(bool setup) async {
     if (state != BootstrapState.askSetupOnlineKeyBackup) {
-      throw 'Bad State';
+      throw BootstrapBadStateException();
     }
     if (!setup) {
       state = BootstrapState.done;
@@ -527,6 +531,7 @@ class Bootstrap {
           '[Bootstrapping] Error setting up online key backup: ' + e.toString(),
           s);
       state = BootstrapState.error;
+      encryption.onError.add(SdkError(exception: e, stackTrace: s));
       return;
     }
     state = BootstrapState.done;
@@ -541,3 +546,11 @@ class Bootstrap {
     }
   }
 }
+
+class BootstrapBadStateException implements Exception {
+  String cause;
+  BootstrapBadStateException([this.cause = 'Bad state']);
+
+  @override
+  String toString() => 'BootstrapBadStateException: $cause';
+}

lib/encryption/utils/key_verification.dart

@@ -114,7 +114,7 @@ _KeyVerificationMethod _makeVerificationMethod(
   if (type == 'm.sas.v1') {
     return _KeyVerificationMethodSas(request: request);
   }
-  throw 'Unkown method type';
+  throw Exception('Unkown method type');
 }
 
 class KeyVerification {
@@ -883,7 +883,7 @@ class _KeyVerificationMethodSas extends _KeyVerificationMethod {
               : theirInfo + ourInfo) +
           request.transactionId;
     } else {
-      throw 'Unknown key agreement protocol';
+      throw Exception('Unknown key agreement protocol');
     }
     return sas.generate_bytes(sasInfo, bytes);
   }
@@ -965,14 +965,14 @@ class _KeyVerificationMethodSas extends _KeyVerificationMethod {
       olmutil.free();
       return ret;
     }
-    throw 'Unknown hash method';
+    throw Exception('Unknown hash method');
   }
 
   String _calculateMac(String input, String info) {
     if (messageAuthenticationCode == 'hkdf-hmac-sha256') {
       return sas.calculate_mac(input, info);
     } else {
-      throw 'Unknown message authentification code';
+      throw Exception('Unknown message authentification code');
     }
   }
 }

lib/matrix_api.dart

@@ -66,4 +66,6 @@ export 'matrix_api/model/upload_key_signatures_response.dart';
 export 'matrix_api/model/user_search_result.dart';
 export 'matrix_api/model/well_known_informations.dart';
 export 'matrix_api/model/who_is_info.dart';
+export 'matrix_api/model/events/secret_storage_default_key_content.dart';
+export 'matrix_api/model/events/secret_storage_key_content.dart';
 export 'matrix_api/model/events/tombstone_content.dart';

lib/matrix_api/model/event_types.dart

@@ -44,6 +44,7 @@ abstract class EventTypes {
 
   static const String CrossSigningSelfSigning = 'm.cross_signing.self_signing';
   static const String CrossSigningUserSigning = 'm.cross_signing.user_signing';
+  static const String CrossSigningMasterKey = 'm.cross_signing.master';
   static const String MegolmBackup = 'm.megolm_backup.v1';
   static const String SecretStorageDefaultKey = 'm.secret_storage.default_key';
   static String secretStorageKey(String keyId) => 'm.secret_storage.key.$keyId';

lib/matrix_api/model/events/secret_storage_default_key_content.dart

@@ -0,0 +1,22 @@
+import 'package:famedlysdk/matrix_api/model/basic_event.dart';
+import '../../utils/try_get_map_extension.dart';
+
+extension SecretStorageDefaultKeyContentBasicEventExtension on BasicEvent {
+  SecretStorageDefaultKeyContent get parsedSecretStorageDefaultKeyContent =>
+      SecretStorageDefaultKeyContent.fromJson(content);
+}
+
+class SecretStorageDefaultKeyContent {
+  String key;
+
+  SecretStorageDefaultKeyContent();
+
+  SecretStorageDefaultKeyContent.fromJson(Map<String, dynamic> json)
+      : key = json.tryGet<String>('key');
+
+  Map<String, dynamic> toJson() {
+    final data = <String, dynamic>{};
+    if (key != null) data['key'] = key;
+    return data;
+  }
+}

lib/matrix_api/model/events/secret_storage_key_content.dart

@@ -0,0 +1,57 @@
+import 'package:famedlysdk/matrix_api/model/basic_event.dart';
+import '../../utils/try_get_map_extension.dart';
+
+extension SecretStorageKeyContentBasicEventExtension on BasicEvent {
+  SecretStorageKeyContent get parsedSecretStorageKeyContent =>
+      SecretStorageKeyContent.fromJson(content);
+}
+
+class SecretStorageKeyContent {
+  PassphraseInfo passphrase;
+  String iv;
+  String mac;
+  String algorithm;
+
+  SecretStorageKeyContent();
+
+  SecretStorageKeyContent.fromJson(Map<String, dynamic> json)
+      : passphrase = json['passphrase'] is Map<String, dynamic>
+            ? PassphraseInfo.fromJson(json['passphrase'])
+            : null,
+        iv = json.tryGet<String>('iv'),
+        mac = json.tryGet<String>('mac'),
+        algorithm = json.tryGet<String>('algorithm');
+
+  Map<String, dynamic> toJson() {
+    final data = <String, dynamic>{};
+    if (passphrase != null) data['passphrase'] = passphrase.toJson();
+    if (iv != null) data['iv'] = iv;
+    if (mac != null) data['mac'] = mac;
+    if (algorithm != null) data['algorithm'] = algorithm;
+    return data;
+  }
+}
+
+class PassphraseInfo {
+  String algorithm;
+  String salt;
+  int iterations;
+  int bits;
+
+  PassphraseInfo();
+
+  PassphraseInfo.fromJson(Map<String, dynamic> json)
+      : algorithm = json.tryGet<String>('algorithm'),
+        salt = json.tryGet<String>('salt'),
+        iterations = json.tryGet<int>('iterations'),
+        bits = json.tryGet<int>('bits');
+
+  Map<String, dynamic> toJson() {
+    final data = <String, dynamic>{};
+    if (algorithm != null) data['algorithm'] = algorithm;
+    if (salt != null) data['salt'] = salt;
+    if (iterations != null) data['iterations'] = iterations;
+    if (bits != null) data['bits'] = bits;
+    return data;
+  }
+}

lib/src/client.dart

@@ -325,7 +325,7 @@ class Client extends MatrixApi {
     if (response.accessToken == null ||
         response.deviceId == null ||
         response.userId == null) {
-      throw 'Registered but token, device ID or user ID is null.';
+      throw Exception('Registered but token, device ID or user ID is null.');
     }
     await init(
         newToken: response.accessToken,
@@ -410,6 +410,7 @@ class Client extends MatrixApi {
     }
   }
 
+  /// Run any request and react on user interactive authentication flows here.
   Future<T> uiaRequestBackground<T>(
       Future<T> Function(Map<String, dynamic> auth) request) {
     final completer = Completer<T>();
@@ -573,6 +574,7 @@ class Client extends MatrixApi {
   final StreamController<SdkError> onSyncError = StreamController.broadcast();
 
   /// Synchronization erros are coming here.
+  @Deprecated('Please use encryption.onToDeviceEventDecryptionError instead')
   final StreamController<ToDeviceEventDecryptionError> onOlmError =
       StreamController.broadcast();
 
@@ -948,22 +950,7 @@ class Client extends MatrixApi {
     for (var i = 0; i < events.length; i++) {
       var toDeviceEvent = ToDeviceEvent.fromJson(events[i].toJson());
       if (toDeviceEvent.type == EventTypes.Encrypted && encryptionEnabled) {
-        try {
+        toDeviceEvent = await encryption.decryptToDeviceEvent(toDeviceEvent);
-          toDeviceEvent = await encryption.decryptToDeviceEvent(toDeviceEvent);
-        } catch (e, s) {
-          Logs.error(
-              '[LibOlm] Could not decrypt to device event from ${toDeviceEvent.sender} with content: ${toDeviceEvent.content}\n${e.toString()}',
-              s);
-
-          onOlmError.add(
-            ToDeviceEventDecryptionError(
-              exception: e is Exception ? e : Exception(e),
-              stackTrace: s,
-              toDeviceEvent: toDeviceEvent,
-            ),
-          );
-          toDeviceEvent = ToDeviceEvent.fromJson(events[i].toJson());
-        }
       }
       if (encryptionEnabled) {
         await encryption.handleToDeviceEvent(toDeviceEvent);

lib/src/utils/device_keys_list.dart

@@ -59,7 +59,7 @@ class DeviceKeysList {
       final roomId =
           await User(userId, room: Room(client: client)).startDirectChat();
       if (roomId == null) {
-        throw 'Unable to start new room';
+        throw Exception('Unable to start new room');
       }
       final room =
           client.getRoomById(roomId) ?? Room(id: roomId, client: client);

lib/src/utils/uia_request.dart

@@ -18,6 +18,7 @@
 
 import '../../famedlysdk.dart';
 
+/// Wrapper to handle User interactive authentication requests
 class UiaRequest<T> {
   void Function() onUpdate;
   void Function() onDone;

test/uia_test.dart

@@ -79,7 +79,7 @@ void main() {
       var finished = false;
       final request = UiaRequest(
         request: (auth) async {
-          throw 'nope';
+          throw Exception('nope');
         },
         onUpdate: () => updated = true,
         onDone: () => finished = true,