diff -r 000000000000 -r 6474c204b198 mobile/android/base/sync/jpake/JPakeJson.java
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mobile/android/base/sync/jpake/JPakeJson.java	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,23 @@
+/* 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.sync.jpake;
+
+import java.math.BigInteger;
+
+import org.mozilla.gecko.sync.ExtendedJSONObject;
+import org.mozilla.gecko.sync.setup.Constants;
+
+public class JPakeJson {
+  /*
+   * Helper function to generate a JSON-encoded ZKP.
+   */
+  public static ExtendedJSONObject makeJZkp(BigInteger gr, BigInteger b, String id) {
+    ExtendedJSONObject result = new ExtendedJSONObject();
+    result.put(Constants.ZKP_KEY_GR, BigIntegerHelper.toEvenLengthHex(gr));
+    result.put(Constants.ZKP_KEY_B, BigIntegerHelper.toEvenLengthHex(b));
+    result.put(Constants.ZKP_KEY_ID, id);
+    return result;
+  }
+}