This was used in the 3301 / Cicada 'games' last year [1]. The only way I know about it. Cicada 'dead-dropped' difference peices of the SSSS code all over the world. We had to recover. One of the guys ended up 'bruting' the final line.

[1] http://uncovering-cicada.wikia.com/wiki/What_Happened_Part_1... (breif overview)