Probably just not savvy enough to crack this 'candidate-interview' puzzle, but the binary doesn't produce any output (Linux, 64-bit). Spent 30-min REing it to find an email address that just bounces... bunch of boiler plate C code from GNU library in there too.

Not sure if I am missing a tool here or if the binary is supposed to do something. Might also want to validate an arbitrary executable somehow (PGP maybe). I ran it in a VM b/c I don't see why I would trust this...