refact: Call key transport, pass the target recipients to sendKey

src/matrixrtc/EncryptionManager.ts

@@ -287,7 +287,7 @@ export class EncryptionManager implements IEncryptionManager {
 
         try {
             this.statistics.counters.roomEventEncryptionKeysSent += 1;
-            await this.transport.sendKey(encodeUnpaddedBase64(keyToSend), keyIndexToSend);
+            await this.transport.sendKey(encodeUnpaddedBase64(keyToSend), keyIndexToSend, this.getMemberships());
             logger.debug(
                 `Embedded-E2EE-LOG updateEncryptionKeyEvent participantId=${this.userId}:${this.deviceId} numKeys=${myKeys.length} currentKeyIndex=${this.currentEncryptionKeyIndex} keyIndexToSend=${keyIndexToSend}`,
                 this.encryptionKeys,

src/matrixrtc/IKeyTransport.ts

@@ -16,6 +16,7 @@ limitations under the License.
 
 import { type MatrixEvent } from "../models/event.ts";
 import { type Statistics } from "./EncryptionManager.ts";
+import { type CallMembership } from "./CallMembership.ts";
 
 /**
  * Generic interface for the transport used to share room keys.
@@ -23,11 +24,12 @@ import { type Statistics } from "./EncryptionManager.ts";
  */
 export interface IKeyTransport {
     /**
-     * Sends the current user media key.
+     * Sends the current user media key to the given members.
      * @param keyBase64Encoded
      * @param index
+     * @param members - The participants that should get they key
      */
-    sendKey(keyBase64Encoded: string, index: number): Promise<void>;
+    sendKey(keyBase64Encoded: string, index: number, members: CallMembership[]): Promise<void>;
 
     /**
      * Takes an incoming event from the transport and extracts the key information.

src/matrixrtc/RoomKeyTransport.ts

@@ -22,6 +22,7 @@ import { logger, type Logger } from "../logger.ts";
 import { type IKeyTransport } from "./IKeyTransport.ts";
 import { type MatrixEvent } from "../models/event.ts";
 import { type Statistics } from "./EncryptionManager.ts";
+import { type CallMembership } from "./CallMembership.ts";
 
 export class RoomKeyTransport implements IKeyTransport {
     private readonly prefixedLogger: Logger;
@@ -33,7 +34,9 @@ export class RoomKeyTransport implements IKeyTransport {
         this.prefixedLogger = logger.getChild(`[RTC: ${roomId} RoomKeyTransport]`);
     }
 
-    public async sendKey(keyBase64Encoded: string, index: number): Promise<void> {
+    /** implements {@link IKeyTransport#sendKey} */
+    public async sendKey(keyBase64Encoded: string, index: number, members: CallMembership[]): Promise<void> {
+        // members not used in room transports as the keys are sent to all room members
         const content: EncryptionKeysEventContent = {
             keys: [
                 {