diff --git a/sea.js b/sea.js
index dd24f41e0..704cf1b7e 100644
--- a/sea.js
+++ b/sea.js
@@ -37,7 +37,9 @@
       if(location.protocol.indexOf('s') < 0
       && location.host.indexOf('localhost') < 0
       && ! /^127\.\d+\.\d+\.\d+$/.test(location.hostname)
-      && location.protocol.indexOf('file:') < 0){
+      && location.protocol.indexOf('blob:') < 0
+      && location.protocol.indexOf('file:') < 0
+      && location.origin != 'null'){
         console.warn('HTTPS needed for WebCrypto in SEA, redirecting...');
         location.protocol = 'https:'; // WebCrypto does NOT work without HTTPS!
       }