Author : ttlhacker challenge files Description : x86_64 linux binary (tested on debian 9 and ubuntu 18.04, should run on any distro). Takes one command line argument and outputs “OK!” if it’s correct, “Wrong” if it’s not. Partially written in C, actual verification routine is assembly. Don’t patch the binary, of course - find the correct input. Lets open the binary in radare2 and we’ll look at the disassembly of the main function