The Kerckhoffs' assumption is generally regarded as a sound principle. It seems though that one of the two binaries was used to encrypt the other, which means the latter has something useful inside. Can you find out what it is? link1 https://s3.amazonaws.com/volgactf/crypto/500/cryptor.rar link2 https://s3.amazonaws.com/volgactf/crypto/500/strange.exe.bin