Vasilisk: Use the cipher on the smallest device you can—ideally a single‑chip microcontroller that consumes a few milliamps. Keep the key short but random, store it in a physically separate chip, and never write it to flash. Run the encryption in a tightly timed, interrupt‑free loop so you can predict exactly how long the signal takes to avoid timing analysis. For communication, piggyback on a covert channel—like a low‑frequency audio burst that blends into ambient noise. Finally, scrub any logs and wipe the RAM immediately after each session so nothing survives a search. That keeps the operation clean and the trail invisible.