Kerckhoffs' Principle:
"A basic principle, adopted by all modern cryptographers, is that the algorithm which defines any cryptosystem must be publicly available. Only then is it possible for the cryptosystem to be subjected to peer review and critical analysis, so that users can have confidence in it".
This means that when a good encryption algorithm is used, the knowledge of the algorithm does not involve any kind of help unless the encryption / decryption key is known.