Practical Secret Protection (PSP)

Alice wants to send a secret to Bob. Alice kills everyone on the planet except Bob, and sends the message in clear. It should be noted that although this method could potentially involve 2^32.5 = 6,000,000 operations, this is significantly fewer than the 2^56 that are required to brute-force attack the simplest cipher known to man.

Thomas Martin, Laurence O'Toole: Practical Secret Protection. Journal of Craptology 2 (2005).