From 795230247d4e17197bb3497419eef1baf414bb21 Mon Sep 17 00:00:00 2001
From: Valere <bill.carson@valrsoft.com>
Date: Tue, 29 Apr 2025 15:56:51 +0200
Subject: [PATCH] WIP ratcheting

---
 package.json                  |  4 ++--
 src/e2ee/matrixKeyProvider.ts | 35 ++++++++++++++++++++++++++++++++---
 2 files changed, 34 insertions(+), 5 deletions(-)

diff --git a/package.json b/package.json
index 6ff4198d..28302e68 100644
--- a/package.json
+++ b/package.json
@@ -99,10 +99,10 @@
     "i18next-parser": "^9.1.0",
     "jsdom": "^26.0.0",
     "knip": "^5.27.2",
-    "livekit-client": "^2.11.3",
+    "livekit-client": "github:BillCarsonFr/client-sdk-js#4ac197085ee063f66b48d8ec24c88b2321fcbf9e",
     "lodash-es": "^4.17.21",
     "loglevel": "^1.9.1",
-    "matrix-js-sdk": "github:matrix-org/matrix-js-sdk#19b1b901f575755d29d1fe03ca48cbf7c1cae05c",
+    "matrix-js-sdk": "github:matrix-org/matrix-js-sdk#44d1a860a1c56a0d4193aa7dcd09e10822398a4d",
     "matrix-widget-api": "1.11.0",
     "normalize.css": "^8.0.1",
     "observable-hooks": "^4.2.3",
diff --git a/src/e2ee/matrixKeyProvider.ts b/src/e2ee/matrixKeyProvider.ts
index 9b190ed8..515fec64 100644
--- a/src/e2ee/matrixKeyProvider.ts
+++ b/src/e2ee/matrixKeyProvider.ts
@@ -5,7 +5,7 @@ SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial
 Please see LICENSE in the repository root for full details.
 */
 
-import { BaseKeyProvider, createKeyMaterialFromBuffer } from "livekit-client";
+import { BaseKeyProvider, createKeyMaterialFromBuffer, importKey, KeyProviderEvent } from "livekit-client";
 import { logger } from "matrix-js-sdk/lib/logger";
 import {
   type MatrixRTCSession,
@@ -15,8 +15,22 @@ import {
 export class MatrixKeyProvider extends BaseKeyProvider {
   private rtcSession?: MatrixRTCSession;
 
+  private readonly onKeyRatchetComplete: (material: ArrayBuffer, keyIndex?: number) => void;
+
   public constructor() {
-    super({ ratchetWindowSize: 10, keyringSize: 256 });
+    super({ ratchetWindowSize: 10, keyringSize: 10 });
+
+    this.onKeyRatchetComplete = (material: ArrayBuffer, keyIndex?: number): void => {
+      logger.debug(`key ratcheted event received for index `, keyIndex );
+      this.rtcSession?.onOwnKeyRatcheted(material, keyIndex).catch((e) => {
+        logger.error(
+          `Failed to ratchet key for livekit room=${this.rtcSession?.room.roomId} keyIndex=${keyIndex}`,
+          e,
+        );
+      });
+    };
+
+    this.on(KeyProviderEvent.RatchetRequestCompleted, this.onKeyRatchetComplete);
   }
 
   public setRTCSession(rtcSession: MatrixRTCSession): void {
@@ -25,6 +39,11 @@ export class MatrixKeyProvider extends BaseKeyProvider {
         MatrixRTCSessionEvent.EncryptionKeyChanged,
         this.onEncryptionKeyChanged,
       );
+      this.rtcSession.off(
+        MatrixRTCSessionEvent.EncryptionKeyQueryRatchetStep,
+        this.doRatchetKey,
+      );
+
     }
 
     this.rtcSession = rtcSession;
@@ -34,17 +53,27 @@ export class MatrixKeyProvider extends BaseKeyProvider {
       this.onEncryptionKeyChanged,
     );
 
+    this.rtcSession.on(
+      MatrixRTCSessionEvent.EncryptionKeyQueryRatchetStep,
+      this.doRatchetKey,
+    );
+
+
     // The new session could be aware of keys of which the old session wasn't,
     // so emit key changed events
     this.rtcSession.reemitEncryptionKeys();
   }
 
+  private doRatchetKey = (participantId:string, keyIndex:number): void => {
+      this.ratchetKey(participantId, keyIndex);
+  }
+
   private onEncryptionKeyChanged = (
     encryptionKey: Uint8Array,
     encryptionKeyIndex: number,
     participantId: string,
   ): void => {
-    createKeyMaterialFromBuffer(encryptionKey).then(
+    importKey(encryptionKey, "HKDF", 'derive').then(
       (keyMaterial) => {
         this.onSetEncryptionKey(keyMaterial, participantId, encryptionKeyIndex);