We are given an iOS app for this challenge. When we run it in the emulator we have some squares to touch. If we select a correct square it turns green and if we get a wrong one it turns yellow and if we touch a wrong one again it turns red and we lose.
The goal is to turn all the squares green to win and get the flag. We could play the game and get lucky or we could try and reverse the program to obtain the key. If we open the binary in IDA there are some interesting functions with win in them. One of them is building an array of bytes at the beginning. We can push ‘R’ on each byte in IDA that is being moved to view the ascii character and view the key.