AES-256 keys sniffed in seconds using €200 of kit a few inches away • The Register

https://www.theregister.co.uk/2017/06/23/aes_256_cracked_50_seconds_200_kit/

Side-channel attacks that monitor a computer’s electromagnetic output to snaffle passwords are nothing new. They usually require direct access to the target system and a lot of expensive machinery – but no longer.

Researchers at Fox‑IT have managed to wirelessly extract secret AES-256 encryption keys from a distance of one metre (3.3 feet) – using €200 (~US$224) worth of parts obtained from a standard electronics store – just by measuring electromagnetic radiation.