diff -r 000000000000 -r 6474c204b198 mobile/android/base/background/fxa/QuickPasswordStretcher.java
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mobile/android/base/background/fxa/QuickPasswordStretcher.java	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,34 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * 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/. */
+
+package org.mozilla.gecko.background.fxa;
+
+import java.io.UnsupportedEncodingException;
+import java.security.GeneralSecurityException;
+import java.util.HashMap;
+import java.util.Map;
+
+import org.mozilla.gecko.sync.Utils;
+
+public class QuickPasswordStretcher implements PasswordStretcher {
+  protected final String password;
+  protected final Map<String, String> cache = new HashMap<String, String>();
+
+  public QuickPasswordStretcher(String password) {
+    this.password = password;
+  }
+
+  public synchronized byte[] getQuickStretchedPW(byte[] emailUTF8) throws UnsupportedEncodingException, GeneralSecurityException {
+    if (emailUTF8 == null) {
+      throw new IllegalArgumentException("emailUTF8 must not be null");
+    }
+    String key = Utils.byte2Hex(emailUTF8);
+    if (!cache.containsKey(key)) {
+      byte[] value = FxAccountUtils.generateQuickStretchedPW(emailUTF8, password.getBytes("UTF-8"));
+      cache.put(key, Utils.byte2Hex(value));
+      return value;
+    }
+    return Utils.hex2Byte(cache.get(key));
+  }
+}