diff --git a/getChallenge.js b/getChallenge.js
index 7a97fd8..a2b7350 100644
--- a/getChallenge.js
+++ b/getChallenge.js
@@ -1,16 +1,17 @@
-export default function() {
-    navigator.requestMediaKeySystemAccess('com.widevine.alpha', config).then(keySystemAccess => {
-        createMediaKeys(keySystemAccess);
-    })
-};
-
-const b64 = {
-    decode: s => Uint8Array.from(atob(s), c => c.charCodeAt(0)),
-    encode: b => btoa(String.fromCharCode(...new Uint8Array(b)))
+export default async function() {
+    let keySystemAccess;
+    try{
+        keySystemAccess = await navigator.requestMediaKeySystemAccess('com.widevine.alpha', config)
+    } catch {
+        config[0]['sessionTypes'] = ['temporary']
+        keySystemAccess = await navigator.requestMediaKeySystemAccess('com.widevine.alpha', config)
+    }
+    let challenge = await getChallenge(keySystemAccess);
+    return challenge
 };
 
 // Tears of Steel Init data Widevine
-let initData = b64.decode('AAAARHBzc2gAAAAA7e+LqXnWSs6jyCfc1R0h7QAAACQIARIBMRoNd2lkZXZpbmVfdGVzdCIKMjAxNV90ZWFycyoCU0Q=')
+let initData = Uint8Array.from(atob('AAAARHBzc2gAAAAA7e+LqXnWSs6jyCfc1R0h7QAAACQIARIBMRoNd2lkZXZpbmVfdGVzdCIKMjAxNV90ZWFycyoCU0Q='), c => c.charCodeAt(0))
 
 // Widevine CDM config MediaKeyAccess default
 let config = [{
@@ -24,22 +25,16 @@ let config = [{
     }]
 }];
 
-async function createMediaKeys(keySystemAccess) {
-    try{
-        let mediaKeys = await keySystemAccess.createMediaKeys();
-        let challenge = await onCreate(mediaKeys);
-        console.log(b64.encode(challenge))
-    } catch(err) {
-        console.error("Unable to create MediaKeys : " + err)
-    }
-}
-
-// Initialization of the CDM session and generation of the request
-function onCreate(mediaKeys) {
-    return new Promise(resolve => {
-        let keySession = mediaKeys.createSession(config[0]['sessionTypes'])
-
-        keySession.addEventListener("message", () => resolve(event.message));
-        keySession.generateRequest("cenc", initData)
+async function getChallenge(keySystemAccess) {
+    return new Promise((resolve, reject) => {
+        try{
+            keySystemAccess.createMediaKeys().then(mediaKeys => {
+                let keySession = mediaKeys.createSession(config[0]['sessionTypes'])
+                keySession.addEventListener("message", () => resolve(event.message));
+                keySession.generateRequest("cenc", initData)
+            })
+        } catch(err) {
+            reject("Unable to create MediaKeys : " + err)
+        }
     })
 }
diff --git a/index.html b/index.html
index 2e75e96..41ace1c 100644
--- a/index.html
+++ b/index.html
@@ -4,7 +4,9 @@
         <script type="module">
             import getChallenge from './getChallenge.js'
             window.onload = () => {
-                getChallenge()
+                let b64encode = b => btoa(String.fromCharCode(...new Uint8Array(b)))
+                let challenge = getChallenge()
+                console.log(challenge)
             }
         </script>
     </head>