diff --git a/js/test.js b/js/test.js
index 889ccf00b7..b5103fe22d 100644
--- a/js/test.js
+++ b/js/test.js
@@ -53,6 +53,18 @@ describe("Cryptographic primitives", function() {
         });
     });
 
+    describe("Encrypt AES-CBC", function() {
+        it('works', function(done) {
+            var key = hexToArrayBuffer('603deb1015ca71be2b73aef0857d77811f352c073b6108d72d9810a30914dff4');
+            var iv = hexToArrayBuffer('000102030405060708090a0b0c0d0e0f');
+            var plaintext  = hexToArrayBuffer('6bc1bee22e409f96e93d7e117393172aae2d8a571e03ac9c9eb76fac45af8e5130c81c46a35ce411e5fbc1191a0a52eff69f2445df4f9b17ad2b417be66c3710');
+            var ciphertext = hexToArrayBuffer('f58c4c04d6e5f1ba779eabfb5f7bfbd69cfc4e967edb808d679f777bc6702c7d39f23369a9d9bacfa530e26304231461b2eb05e2c39be9fcda6c19078c6a9d1b3f461796d6b0d6b2e0c2a72b4d80e644');
+            return window.textsecure.subtle.encrypt({name: "AES-CBC", iv: iv}, key, plaintext).then(function(result) {
+                assert.strictEqual(getString(result), getString(ciphertext));
+			}).then(done).catch(done);
+        });
+    });
+
     describe("Decrypt AES-CBC", function() {
         it('works', function(done) {
             var key = hexToArrayBuffer('603deb1015ca71be2b73aef0857d77811f352c073b6108d72d9810a30914dff4');
diff --git a/js/webcrypto.js b/js/webcrypto.js
index 71d3ce23be..b64fadad23 100644
--- a/js/webcrypto.js
+++ b/js/webcrypto.js
@@ -62,10 +62,10 @@ window.textsecure.subtle = (function() {
             assertIsArrayBuffer(plaintext);
             assertIsArrayBuffer(key);
             assertIsArrayBuffer(iv);
-            return CryptoJS.AES.encrypt(btoa(getString(plaintext)),
+            return CryptoJS.AES.encrypt(CryptoJS.enc.Latin1.parse(getString(plaintext)),
                     CryptoJS.enc.Latin1.parse(getString(key)),
                     {iv: CryptoJS.enc.Latin1.parse(getString(iv))})
-                .toString(CryptoJS.enc.Latin1);
+                .ciphertext.toString(CryptoJS.enc.Latin1);
         };
         function decryptAESCBC(ciphertext, key, iv) {
             assertIsArrayBuffer(ciphertext);