diff --git a/js/axolotl_store.js b/js/axolotl_store.js
index bfcdee07d..4c3ac5033 100644
--- a/js/axolotl_store.js
+++ b/js/axolotl_store.js
@@ -259,7 +259,7 @@
                 publicKey = convertToArrayBuffer(publicKey);
             }
             var number = textsecure.utils.unencodeNumber(identifier)[0];
-            return new Promise(function(resolve) {
+            return new Promise(function(resolve, reject) {
                 var identityKey = new IdentityKey({id: number});
                 identityKey.fetch().always(function() {
                     var oldpublicKey = identityKey.get('publicKey');
@@ -271,7 +271,7 @@
                         if (equalArrayBuffers(oldpublicKey, publicKey)) {
                             resolve();
                         } else {
-                            throw new Error("Attempted to overwrite a different identity key");
+                            reject(new Error("Attempted to overwrite a different identity key"));
                         }
                     }
                 });
diff --git a/libtextsecure/test/device_storage_test.js b/libtextsecure/test/device_storage_test.js
new file mode 100644
index 000000000..084039bf3
--- /dev/null
+++ b/libtextsecure/test/device_storage_test.js
@@ -0,0 +1,50 @@
+/* vim: ts=4:sw=4
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+'use strict';
+
+describe('Device storage', function() {
+    before(function() { localStorage.clear(); });
+    var store = textsecure.storage.axolotl;
+    var identifier = '+5558675309';
+    var another_identifier = '+5555590210';
+    var identityKey = {
+        pubKey: textsecure.crypto.getRandomBytes(33),
+        privKey: textsecure.crypto.getRandomBytes(32),
+    };
+    var testKey = {
+        pubKey: textsecure.crypto.getRandomBytes(33),
+        privKey: textsecure.crypto.getRandomBytes(32),
+    };
+    describe('saveKeysToDeviceObject', function() {
+        it('rejects if the identity key changes', function(done) {
+            return textsecure.storage.devices.saveKeysToDeviceObject({
+                identityKey: identityKey.pubKey,
+                encodedNumber: identifier + '.1'
+            }).then(function() {
+                textsecure.storage.devices.saveKeysToDeviceObject({
+                    identityKey: testKey.pubKey,
+                    encodedNumber: identifier + '.1'
+                }).then(function() {
+                    done(new Error('Allowed to overwrite identity key'));
+                }).catch(function(e) {
+                    assert.strictEqual(e.message, 'Identity key changed');
+                    done();
+                });
+            });
+        });
+    });
+});
diff --git a/libtextsecure/test/index.html b/libtextsecure/test/index.html
index 312d959bb..8090f0c92 100644
--- a/libtextsecure/test/index.html
+++ b/libtextsecure/test/index.html
@@ -52,6 +52,7 @@
   <script type="text/javascript" src="helpers_test.js"></script>
   <script type="text/javascript" src="websocket-resources_test.js"></script>
   <script type="text/javascript" src="storage_test.js"></script>
+  <script type="text/javascript" src="device_storage_test.js"></script>
   <script type="text/javascript" src="contacts_parser_test.js"></script>
   <script type="text/javascript" src="generate_keys_test.js"></script>
   <script type="text/javascript" src="websocket_test.js"></script>
diff --git a/test/storage_test.js b/test/storage_test.js
index 37c77fead..c7346e458 100644
--- a/test/storage_test.js
+++ b/test/storage_test.js
@@ -50,6 +50,17 @@ describe("AxolotlStore", function() {
             });
         }).then(done,done);
     });
+    it('rejects on key change', function(done) {
+        var newIdentity = textsecure.crypto.getRandomBytes(33);
+        store.putIdentityKey(identifier, testKey.pubKey).then(function() {
+            store.putIdentityKey(identifier, newIdentity).then(function() {
+                done(new Error('Allowed to overwrite identity key'));
+            }).catch(function(e) {
+                assert(e instanceof Error);
+                done();
+            });
+        });
+    });
     it('stores prekeys', function(done) {
         store.putPreKey(1, testKey).then(function() {
             return store.getPreKey(1).then(function(key) {