webcrypto utf8 encoding fix

app/assets/javascripts/app/services/helpers/webcrypto.js

@@ -90,16 +90,20 @@ class SNCryptoWeb extends SNCrypto {
 
   stringToArrayBuffer(string) {
     // not available on Edge/IE
-    // var encoder = new TextEncoder("utf-8");
-    // var result = encoder.encode(string);
-
-     var buf = new ArrayBuffer(string.length);
-     var bufView = new Uint8Array(buf);
-     for (var i=0, strLen=string.length; i<strLen; i++) {
-       bufView[i] = string.charCodeAt(i);
-     }
-     return buf;
-   }
+    if(window.TextEncoder) {
+      var encoder = new TextEncoder("utf-8");
+      var result = encoder.encode(string);
+      return result;
+    } else {
+      string = unescape(encodeURIComponent(string));
+      var buf = new ArrayBuffer(string.length);
+      var bufView = new Uint8Array(buf);
+      for (var i=0, strLen=string.length; i<strLen; i++) {
+        bufView[i] = string.charCodeAt(i);
+      }
+      return buf;
+    }
+  }
 
   arrayBufferToHexString(arrayBuffer) {
       var byteArray = new Uint8Array(arrayBuffer);