Merge pull request #19 from flutter-webrtc/feat/frame-cryptor-interface

feat: frame cryptor.

Author: cloudwebrtc

lib/src/factory.dart

@@ -1,3 +1,4 @@
+import 'frame_cryptor.dart';
 import 'media_recorder.dart';
 import 'media_stream.dart';
 import 'navigator.dart';
@@ -21,4 +22,6 @@ abstract class RTCFactory {
   VideoRenderer videoRenderer();
 
   Navigator get navigator;
+
+  FrameCryptorFactory get frameCryptorFactory;
 }

lib/src/frame_cryptor.dart

@@ -0,0 +1,118 @@
+import 'dart:typed_data';
+
+import 'rtc_rtp_receiver.dart';
+import 'rtc_rtp_sender.dart';
+
+/// Built-in Algorithm.
+enum Algorithm {
+  kAesGcm,
+  kAesCbc,
+}
+
+class KeyProviderOptions {
+  KeyProviderOptions({
+    required this.sharedKey,
+    required this.ratchetSalt,
+    required this.ratchetWindowSize,
+    this.uncryptedMagicBytes,
+  });
+  bool sharedKey;
+  Uint8List ratchetSalt;
+  Uint8List? uncryptedMagicBytes;
+  int ratchetWindowSize;
+  Map<String, dynamic> toJson() {
+    return {
+      'sharedKey': sharedKey,
+      'ratchetSalt': ratchetSalt,
+      if (uncryptedMagicBytes != null)
+        'uncryptedMagicBytes': uncryptedMagicBytes,
+      'ratchetWindowSize': ratchetWindowSize,
+    };
+  }
+}
+
+/// Shared secret key for frame encryption.
+abstract class KeyProvider {
+  /// The unique identifier of the key provider.
+  String get id;
+
+  /// Set the raw key at the given index.
+  Future<bool> setKey({
+    required String participantId,
+    required int index,
+    required Uint8List key,
+  });
+
+  /// ratchet the key at the given index.
+  Future<Uint8List> ratchetKey({
+    required String participantId,
+    required int index,
+  });
+
+  /// Dispose the key manager.
+  Future<void> dispose();
+}
+
+enum FrameCryptorState {
+  FrameCryptorStateNew,
+  FrameCryptorStateOk,
+  FrameCryptorStateEncryptionFailed,
+  FrameCryptorStateDecryptionFailed,
+  FrameCryptorStateMissingKey,
+  FrameCryptorStateKeyRatcheted,
+  FrameCryptorStateInternalError,
+}
+
+/// Frame encryption/decryption.
+///
+abstract class FrameCryptor {
+  FrameCryptor();
+
+  Function(String participantId, FrameCryptorState state)?
+      onFrameCryptorStateChanged;
+
+  /// The unique identifier of the frame cryptor.
+  String get participantId;
+
+  /// Enable/Disable frame crypto for the sender or receiver.
+  Future<bool> setEnabled(bool enabled);
+
+  /// Get the enabled state for the sender or receiver.
+  Future<bool> get enabled;
+
+  /// Set the key index for the sender or receiver.
+  /// If the key index is not set, the key index will be set to 0.
+  Future<bool> setKeyIndex(int index);
+
+  /// Get the key index for the sender or receiver.
+  Future<int> get keyIndex;
+
+  Future<void> updateCodec(String codec);
+
+  /// Dispose the frame cryptor.
+  Future<void> dispose();
+}
+
+/// Factory for creating frame Cryptors.
+/// For End 2 End Encryption, you need to create a [KeyProvider] for each peer.
+/// And set your key in keyProvider.
+abstract class FrameCryptorFactory {
+  /// Shared key manager.
+  Future<KeyProvider> createDefaultKeyProvider(KeyProviderOptions options);
+
+  /// Create a frame Cryptor from a [RTCRtpSender].
+  Future<FrameCryptor> createFrameCryptorForRtpSender({
+    required String participantId,
+    required RTCRtpSender sender,
+    required Algorithm algorithm,
+    required KeyProvider keyProvider,
+  });
+
+  /// Create a frame Cryptor from a [RTCRtpReceiver].
+  Future<FrameCryptor> createFrameCryptorForRtpReceiver({
+    required String participantId,
+    required RTCRtpReceiver receiver,
+    required Algorithm algorithm,
+    required KeyProvider keyProvider,
+  });
+}

lib/webrtc_interface.dart

@@ -2,6 +2,7 @@ library webrtc_interface;
 
 export 'src/enums.dart';
 export 'src/factory.dart';
+export 'src/frame_cryptor.dart';
 export 'src/media_recorder.dart';
 export 'src/media_stream.dart';
 export 'src/media_stream_track.dart';