diff --git a/components/script/dom/globalscope.rs b/components/script/dom/globalscope.rs
index de9ee3773d2..0eaf631f0e1 100644
--- a/components/script/dom/globalscope.rs
+++ b/components/script/dom/globalscope.rs
@@ -2,19 +2,23 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
+use dom::bindings::js::{JS, MutNullableHeap, Root};
 use dom::bindings::reflector::Reflectable;
+use dom::crypto::Crypto;
 use dom::eventtarget::EventTarget;
 use js::jsapi::{JS_GetContext, JS_GetObjectRuntime, JSContext};
 
 #[dom_struct]
 pub struct GlobalScope {
     eventtarget: EventTarget,
+    crypto: MutNullableHeap<JS<Crypto>>,
 }
 
 impl GlobalScope {
     pub fn new_inherited() -> GlobalScope {
         GlobalScope {
             eventtarget: EventTarget::new_inherited(),
+            crypto: Default::default(),
         }
     }
 
@@ -29,4 +33,8 @@ impl GlobalScope {
             context
         }
     }
+
+    pub fn crypto(&self) -> Root<Crypto> {
+        self.crypto.or_init(|| Crypto::new(self))
+    }
 }
diff --git a/components/script/dom/window.rs b/components/script/dom/window.rs
index 0b764f6fa05..148ee2f5eed 100644
--- a/components/script/dom/window.rs
+++ b/components/script/dom/window.rs
@@ -157,7 +157,6 @@ pub struct Window {
     history_traversal_task_source: HistoryTraversalTaskSource,
     #[ignore_heap_size_of = "task sources are hard"]
     file_reading_task_source: FileReadingTaskSource,
-    crypto: MutNullableHeap<JS<Crypto>>,
     navigator: MutNullableHeap<JS<Navigator>>,
     #[ignore_heap_size_of = "channels are hard"]
     image_cache_thread: ImageCacheThread,
@@ -505,7 +504,7 @@ impl WindowMethods for Window {
 
     // https://dvcs.w3.org/hg/webcrypto-api/raw-file/tip/spec/Overview.html#dfn-GlobalCrypto
     fn Crypto(&self) -> Root<Crypto> {
-        self.crypto.or_init(|| Crypto::new(self.upcast()))
+        self.upcast::<GlobalScope>().crypto()
     }
 
     // https://html.spec.whatwg.org/multipage/#dom-frameelement
@@ -1638,7 +1637,6 @@ impl Window {
             history_traversal_task_source: history_task_source,
             file_reading_task_source: file_task_source,
             image_cache_chan: image_cache_chan,
-            crypto: Default::default(),
             navigator: Default::default(),
             image_cache_thread: image_cache_thread,
             mem_profiler_chan: mem_profiler_chan,
diff --git a/components/script/dom/workerglobalscope.rs b/components/script/dom/workerglobalscope.rs
index 83cef1d994f..739e81c87ac 100644
--- a/components/script/dom/workerglobalscope.rs
+++ b/components/script/dom/workerglobalscope.rs
@@ -89,7 +89,6 @@ pub struct WorkerGlobalScope {
     resource_threads: ResourceThreads,
     location: MutNullableHeap<JS<WorkerLocation>>,
     navigator: MutNullableHeap<JS<WorkerNavigator>>,
-    crypto: MutNullableHeap<JS<Crypto>>,
     timers: OneshotTimers,
 
     #[ignore_heap_size_of = "Defined in std"]
@@ -147,7 +146,6 @@ impl WorkerGlobalScope {
             resource_threads: init.resource_threads,
             location: Default::default(),
             navigator: Default::default(),
-            crypto: Default::default(),
             timers: OneshotTimers::new(timer_event_chan, init.scheduler_chan.clone()),
             mem_profiler_chan: init.mem_profiler_chan,
             time_profiler_chan: init.time_profiler_chan,
@@ -343,7 +341,7 @@ impl WorkerGlobalScopeMethods for WorkerGlobalScope {
 
     // https://html.spec.whatwg.org/multipage/#dfn-Crypto
     fn Crypto(&self) -> Root<Crypto> {
-        self.crypto.or_init(|| Crypto::new(self.upcast()))
+        self.upcast::<GlobalScope>().crypto()
     }
 
     // https://html.spec.whatwg.org/multipage/#dom-windowbase64-btoa