mozilla-services/android-sync — comment on commit 0377ca8342f658826ac3e83939b8961594dc3f21
File: src/main/java/org/mozilla/gecko/sync/Utils.java line 114
By rnewman:

If we're using SecureRandom, we should use one static instance. Initialization of it is slow.

SecureRandom is thread-safe, so go ahead and lift this into Utils as a static. Add a public static method to call

Utils.sharedRandom.setSeed(Utils.sharedRandom.generateSeed(System.nanoTime()));

and invoke that method from SyncAdapter.onPerformSync() to ensure that we don't work with the same seed material for too long.