diff --git a/node/package.json b/node/package.json
index fb0b8e0..536be50 100644
--- a/node/package.json
+++ b/node/package.json
@@ -19,6 +19,7 @@
   },
   "dependencies": {
     "arg": "^4.1.3",
+    "hash-wasm": "^4.8.0",
     "node-kakao": "4.5.0",
     "systemd-daemon": "^1.1.2"
   },
diff --git a/node/src/client.js b/node/src/client.js
index 15b71f5..801a5c6 100644
--- a/node/src/client.js
+++ b/node/src/client.js
@@ -40,6 +40,7 @@ const { OpenChannelUserPerm } = openlink
 import chat from "node-kakao/chat"
 const { KnownChatType } = chat
 
+import * as modutil from "./modutil.js"
 import { emitLines, promisify } from "./util.js"
 
 /**
@@ -581,7 +582,7 @@ export default class PeerClient {
 	 * @param {string} uuid
 	 */
 	async #createAuthClient(uuid) {
-		return await AuthApiClient.create(this.deviceName, uuid)
+		return await AuthApiClient.create(this.deviceName, uuid, {}, modutil.ModXVCProvider)
 	}
 
 	// TODO Wrapper for per-user commands
diff --git a/node/src/modutil.js b/node/src/modutil.js
new file mode 100644
index 0000000..c1ea1da
--- /dev/null
+++ b/node/src/modutil.js
@@ -0,0 +1,28 @@
+// matrix-appservice-kakaotalk - A Matrix-KakaoTalk puppeting bridge.
+// Copyright (C) 2022 Tulir Asokan, Andrew Ferrazzutti
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+import { sha512 } from "hash-wasm"
+import { DefaultConfiguration } from "node-kakao"
+
+
+DefaultConfiguration.version = "3.4.2"
+DefaultConfiguration.appVersion = "3.4.2.3187"
+
+export const ModXVCProvider = {
+	toFullXVCKey(deviceUUID, userAgent, email) {
+		const source = `WINTER|${userAgent}|ARTHUR|${email}|${deviceUUID}`
+		return sha512(source)
+	}
+}
\ No newline at end of file