diff --git a/sha1-hmac.js b/sha1-hmac.js
index fb107ee..df419e1 100644
--- a/sha1-hmac.js
+++ b/sha1-hmac.js
@@ -12,8 +12,19 @@ exports.sha1Hmac = function (key, bytes) {
 
   var Unibabel = window.Unibabel;
 
-  if (window.crypto) {
-    return window.crypto.subtle.importKey(
+  function useForge() {
+    var forge = window.forge;
+    var hmac = forge.hmac.create();
+    var digest;
+    hmac.start('sha1', Unibabel.bufferToBinaryString(key));
+    hmac.update(Unibabel.bufferToBinaryString(bytes));
+    digest = hmac.digest().toHex();
+
+    return window.Promise.resolve(digest);
+  }
+
+  function useWebCrypto() {
+    return (window.crypto.subtle||window.crypto.webkitSubtle).importKey(
       "raw"
     , key
     , {  name: "HMAC"
@@ -40,10 +51,10 @@ exports.sha1Hmac = function (key, bytes) {
       ["sign", "verify"] //can be any combination of "sign" and "verify"
     )
     */
-    .then(function (key) {
-      return window.crypto.subtle.sign(
+    .then(function (cryptoKey) {
+      return (window.crypto.subtle||window.crypto.webkitSubtle).sign(
         { name: "HMAC" }
-      , key  // from generateKey or importKey above
+      , cryptoKey  // from generateKey or importKey above
       , new Uint8Array(bytes) // ArrayBuffer of data you want to sign
       )
       .then(function(signature){
@@ -52,15 +63,29 @@ exports.sha1Hmac = function (key, bytes) {
       });
     });
   }
-  else if (window.forge) {
-    var forge = window.forge;
-    var hmac = forge.hmac.create();
-    var digest;
-    hmac.start('sha1', Unibabel.bufferToBinaryString(key));
-    hmac.update(Unibabel.bufferToBinaryString(bytes));
-    digest = hmac.digest().toHex();
 
-    return window.Promise.resolve(digest);
+  if (window.crypto) {
+    // WebCrypto is so unreliable right now... ugh...
+    try {
+      return useWebCrypto().then(function (result) {
+        return result;
+      }, function (err) {
+        console.warn(err);
+        console.warn(err.stack);
+        console.warn("WebCrypto failed, trying forge.js");
+
+        return useForge();
+      });
+    } catch(e) {
+      console.warn(e);
+      console.warn(e.stack);
+      console.warn("WebCrypto threw exception, trying forge.js");
+
+      return useForge();
+    }
+  }
+  else if (window.forge) {
+    return useForge();
   }
   else {
     throw new Error("WebCrypto or forge.js is required to create a sha1 hmac");