"And don't forget Kerckhoff's assumption: If the strength of your new cryptosystem relies on the fact that the attacker does not know the algorithm's inner workings, you're sunk. If you believe that keeping the algorithm's insides secret improves the security of your cryptosystem more than letting the academic community analyze it, you're wrong. And if you think that someone won't disassemble your code and reverse-engineer your algorithm, you're naive. The best algorithms we have are ones that have been made public, have been attacked by the world's best cryptographers for years, and are still unbreakable."
--Bruce Scheier; Applied Cryptography (Second Edition); page 7