By Ethan Heilman (Boston Uni), Neha Narula (MIT Media Lab), Garrett Tanzer (Harvard), James Lovejoy (MIT Media Lab), Michael Colavita (Harvard), Madars Virza (MIT Media Lab), and Tadge Dryja (MIT Media Lab). Accepted at the FSE (Fast Software Encryption) Conference , which is organized by the International Association for Cryptologic Research (IACR), 2020