diff --git a/oauth3.crypto.js b/oauth3.crypto.js
index d87a158..bb83280 100644
--- a/oauth3.crypto.js
+++ b/oauth3.crypto.js
@@ -8,6 +8,9 @@
     OAUTH3.crypto.core = require('./oauth3.node.crypto');
   } catch (error) {
     OAUTH3.crypto.core = {};
+    OAUTH3.crypto.core.ready = false;
+    var finishBeforeReady = [];
+    var deferedCalls = [];
 
     // We don't currently have a fallback method for this function, so we assign
     // it directly to the core object instead of the webCrypto object.
@@ -17,10 +20,31 @@
     };
 
     var webCrypto = {};
+
+    var deferCryptoCall = function(name) {
+      return function() {
+        var args = arguments;
+        return new OAUTH3.PromiseA(function(resolve, reject) {
+          deferedCalls.push(function(){
+            try {
+              webCrypto[name].apply(webCrypto, args)
+                .then(function(result){
+                  resolve(result);
+                });
+            } catch(e) {
+              reject(e);
+            }
+          });
+        });
+      };
+    };
+
+    OAUTH3.crypto.core.sha256 = deferCryptoCall("sha256");
     webCrypto.sha256 = function (buf) {
       return OAUTH3._browser.window.crypto.subtle.digest({name: 'SHA-256'}, buf);
     };
 
+    OAUTH3.crypto.core.pbkdf2 = deferCryptoCall("pbkdf2");
     webCrypto.pbkdf2 = function (password, salt) {
       return OAUTH3._browser.window.crypto.subtle.importKey('raw', OAUTH3._binStr.binStrToBuffer(password), {name: 'PBKDF2'}, false, ['deriveKey'])
         .then(function (key) {
@@ -32,12 +56,15 @@
         });
     };
 
+    OAUTH3.crypto.core.encrypt = deferCryptoCall("encrypt");
     webCrypto.encrypt = function (rawKey, iv, data) {
       return OAUTH3._browser.window.crypto.subtle.importKey('raw', rawKey, {name: 'AES-GCM'}, false, ['encrypt'])
         .then(function (key) {
           return OAUTH3._browser.window.crypto.subtle.encrypt({name: 'AES-GCM', iv: iv}, key, data);
         });
     };
+
+    OAUTH3.crypto.core.decrypt = deferCryptoCall("decrypt");
     webCrypto.decrypt = function (rawKey, iv, data) {
       return OAUTH3._browser.window.crypto.subtle.importKey('raw', rawKey, {name: 'AES-GCM'}, false, ['decrypt'])
         .then(function (key) {
@@ -45,6 +72,7 @@
         });
     };
 
+    OAUTH3.crypto.core.genEcdsaKeyPair = deferCryptoCall("genEcdsaKeyPair");
     webCrypto.genEcdsaKeyPair = function () {
       return OAUTH3._browser.window.crypto.subtle.generateKey({name: 'ECDSA', namedCurve: 'P-256'}, true, ['sign', 'verify'])
         .then(function (keyPair) {
@@ -57,6 +85,7 @@
         });
     };
 
+    OAUTH3.crypto.core.sign = deferCryptoCall("sign");
     webCrypto.sign = function (jwk, msg) {
       return OAUTH3._browser.window.crypto.subtle.importKey('jwk', jwk, {name: 'ECDSA', namedCurve: jwk.crv}, false, ['sign'])
         .then(function (key) {
@@ -66,6 +95,8 @@
           return new Uint8Array(sig);
         });
     };
+    
+    OAUTH3.crypto.core.verify = deferCryptoCall("verify");
     webCrypto.verify = function (jwk, msg, signature) {
       // If the JWK has properties that should only exist on the private key or is missing
       // "verify" in the key_ops, importing in as a public key won't work.
@@ -103,18 +134,19 @@
         return prom;
       };
       function checkException(name, func) {
-        OAUTH3.PromiseA.resolve().then(func)
+        return OAUTH3.PromiseA.resolve().then(func)
           .then(function () {
             OAUTH3.crypto.core[name] = webCrypto[name];
           }, function (err) {
             console.warn('error with WebCrypto', name, '- using fallback', err);
-            loadFallback().then(function () {
+            return loadFallback().then(function () {
               OAUTH3.crypto.core[name] = OAUTH3_crypto_fallback[name];
             });
           });
       }
       function checkResult(name, expected, func) {
-        checkException(name, function () {
+        
+        finishBeforeReady.push(checkException(name, function () {
           return func()
             .then(function (result) {
               if (typeof expected === typeof result) {
@@ -127,7 +159,7 @@
                 throw new Error("result ("+result+") doesn't match expectation ("+expected+")");
               }
             });
-        });
+        }));
       }
 
       var zeroBuf = new Uint8Array([0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0]);
@@ -159,12 +191,20 @@
         return webCrypto.verify(jwk, dataBuf, sig);
       });
       // The results of these functions are less predictable, so we can't check their return value.
-      checkException('genEcdsaKeyPair', function () {
+      finishBeforeReady.push(checkException('genEcdsaKeyPair', function () {
         return webCrypto.genEcdsaKeyPair();
-      });
-      checkException('sign', function () {
+      }));
+      finishBeforeReady.push(checkException('sign', function () {
         return webCrypto.sign(jwk, dataBuf);
-      });
+      }));
+      
+      OAUTH3.PromiseA.all(finishBeforeReady)
+        .then(function(results) {
+          OAUTH3.crypto.core.ready = true;
+          deferedCalls.forEach(function(request) {
+            request();
+          });
+        });
     }
     checkWebCrypto();
   }