ShaFuck
From Esolang
ShaFuck is a version of Brainfuck that is intended to be nigh-on impossible to write.
A ShaFuck program may be any sequence of bytes of a length greater than zero which is a multiple of 1024. The SHA-1 sum of every 1024-byte chunk is calculated, and all of the SHA-1 sums are then concatenated. This sequence of SHA-1 sums is interpreted as Brainfuck code, with the caveat that comments are not allowed. Each 1024-byte chunk in the source therefore represents 20 Brainfuck operations.
A ShaFuck interpreter written by Gregor Richards is available at http://codu.org/eso/shafuck/ .
