feat: add keyRingSize/discardFrameWhenCryptorNotReady to KeyProviderOptions.

Author: cloudwebrtc

lib/src/e2ee.worker/e2ee.cryptor.dart

@@ -301,6 +301,9 @@ class FrameCryptor {
     if (!enabled ||
         // skip for encryption for empty dtx frames
         buffer.isEmpty) {
+      if (keyOptions.discardFrameWhenCryptorNotReady) {
+        return;
+      }
       controller.enqueue(frame);
       return;
     }
@@ -405,6 +408,9 @@ class FrameCryptor {
         // skip for encryption for empty dtx frames
         buffer.isEmpty) {
       sifGuard.recordUserFrame();
+      if (keyOptions.discardFrameWhenCryptorNotReady) {
+        return;
+      }
       controller.enqueue(frame);
       return;
     }

lib/src/e2ee.worker/e2ee.keyhandler.dart

@@ -8,19 +8,25 @@ import 'crypto.dart' as crypto;
 import 'e2ee.logger.dart';
 import 'e2ee.utils.dart';
 
+const KEYRING_SIZE = 16;
+
 class KeyOptions {
   KeyOptions({
     required this.sharedKey,
     required this.ratchetSalt,
     required this.ratchetWindowSize,
     this.uncryptedMagicBytes,
     this.failureTolerance = -1,
+    this.keyRingSze = KEYRING_SIZE,
+    this.discardFrameWhenCryptorNotReady = false,
   });
   bool sharedKey;
   Uint8List ratchetSalt;
   int ratchetWindowSize = 0;
   int failureTolerance;
   Uint8List? uncryptedMagicBytes;
+  int keyRingSze;
+  bool discardFrameWhenCryptorNotReady;
 
   @override
   String toString() {
@@ -77,8 +83,6 @@ class KeyProvider {
   }
 }
 
-const KEYRING_SIZE = 16;
-
 class KeySet {
   KeySet(this.material, this.encryptionKey);
   web.CryptoKey material;
@@ -90,10 +94,15 @@ class ParticipantKeyHandler {
     required this.worker,
     required this.keyOptions,
     required this.participantIdentity,
-  });
+  }) {
+    if (keyOptions.keyRingSze <= 0 || keyOptions.keyRingSze > 255) {
+      throw Exception('Invalid key ring size');
+    }
+    cryptoKeyRing = List.filled(keyOptions.keyRingSze, null);
+  }
   int currentKeyIndex = 0;
 
-  List<KeySet?> cryptoKeyRing = List.filled(KEYRING_SIZE, null);
+  late List<KeySet?> cryptoKeyRing;
 
   bool _hasValidKey = false;
 

lib/src/e2ee.worker/e2ee.worker.dart

@@ -118,7 +118,10 @@ void main() async {
                 uncryptedMagicBytes: options['uncryptedMagicBytes'] != null
                     ? Uint8List.fromList(
                         base64Decode(options['uncryptedMagicBytes'] as String))
-                    : null);
+                    : null,
+                keyRingSze: options['keyRingSize'] ?? KEYRING_SIZE,
+                discardFrameWhenCryptorNotReady:
+                    options['discardFrameWhenCryptorNotReady'] ?? false);
             logger.config(
                 'Init with keyProviderOptions:\n ${keyProviderOptions.toString()}');
 

lib/src/frame_cryptor_impl.dart

@@ -193,6 +193,9 @@ class KeyProviderImpl implements KeyProvider {
           'ratchetWindowSize': options.ratchetWindowSize,
           if (options.uncryptedMagicBytes != null)
             'uncryptedMagicBytes': base64Encode(options.uncryptedMagicBytes!),
+          'keyRingSize': options.keyRingSize,
+          'discardFrameWhenCryptorNotReady':
+              options.discardFrameWhenCryptorNotReady,
         },
       })
     ]);

pubspec.yaml

@@ -14,7 +14,7 @@ dependencies:
   platform_detect: ^2.0.7
   synchronized: ^3.0.0+3
   web: ^0.5.1
-  webrtc_interface: ^1.1.2
+  webrtc_interface: ^1.2.0
 
 dev_dependencies:
   build_runner: ^2.3.3

web/main.dart

@@ -1,3 +1,4 @@
+import 'dart:async';
 import 'dart:typed_data';
 
 import 'package:dart_webrtc/dart_webrtc.dart';
@@ -49,7 +50,8 @@ void loopBackTest() async {
       sharedKey: false,
       ratchetWindowSize: 16,
       failureTolerance: -1,
-      ratchetSalt: Uint8List.fromList('testSalt'.codeUnits));
+      ratchetSalt: Uint8List.fromList('testSalt'.codeUnits),
+      discardFrameWhenCryptorNotReady: true);
   var keyProvider =
       await frameCryptorFactory.createDefaultKeyProvider(keyProviderOptions);
 
@@ -73,7 +75,14 @@ void loopBackTest() async {
         receiver: event.receiver!,
         algorithm: Algorithm.kAesGcm,
         keyProvider: keyProvider);
-    await fc.setEnabled(true);
+    if (keyProviderOptions.discardFrameWhenCryptorNotReady) {
+      Timer(Duration(seconds: 2), () {
+        fc.setEnabled(true);
+      });
+    } else {
+      await fc.setEnabled(true);
+    }
+
     await fc.setKeyIndex(0);
     await fc.updateCodec('vp8');
     pc2FrameCryptors.add(fc);