diff --git a/src/matrix/e2ee/common.js b/src/matrix/e2ee/common.js
index 190f2fa2..52995765 100644
--- a/src/matrix/e2ee/common.js
+++ b/src/matrix/e2ee/common.js
@@ -17,7 +17,7 @@ limitations under the License.
 import anotherjson from "../../../lib/another-json/index.js";
 import {createEnum} from "../../utils/enum.js";
 
-export const DecryptionSource = createEnum(["Sync", "Timeline", "Retry"]);
+export const DecryptionSource = createEnum("Sync", "Timeline", "Retry");
 
 // use common prefix so it's easy to clear properties that are not e2ee related during session clear
 export const SESSION_KEY_PREFIX = "e2ee:";
diff --git a/src/utils/enum.js b/src/utils/enum.js
index 733a548b..4defcfd7 100644
--- a/src/utils/enum.js
+++ b/src/utils/enum.js
@@ -17,6 +17,9 @@ limitations under the License.
 export function createEnum(...values) {
     const obj = {};
     for (const value of values) {
+        if (typeof value !== "string") {
+            throw new Error("Invalid enum value name" + value?.toString());
+        }
         obj[value] = value;
     }
     return Object.freeze(obj);