diff --git a/www/js/util.js b/www/js/util.js
index bd2278e..dadeb99 100644
--- a/www/js/util.js
+++ b/www/js/util.js
@@ -31,7 +31,9 @@ const PACK = {
         for(let i = 0; i < bytes.length; ++i) {
             str += String.fromCharCode(bytes[i]);
         }
-        return window.btoa(str);
+        let enc = window.btoa(str);
+        enc.replace("/", "-");
+        return enc;
     },
 };
 
@@ -129,6 +131,7 @@ const UNPACK = {
         return str;
     },
     base64(data) {
+        data.replace("-", "/");
         let str = window.atob(data);
         let bytes = new Uint8Array(str.length);
         for(let i = 0; i < bytes.length; ++i) {