@icon_of_computational_sin Rolling your own crypto is fine, just don't delude yourself into thinking it's secure and actually use it, until at least many people have looked at nobody has worked out how to break it (most hand-rolled crypto falls apart in minutes or hours even if it's beyond you to break it, if someone else looks at it).

The more complicated you make a cryptographic protocol, the higher the chance it has a cryptographic flaw - the simpler the protocol, the better, as nothing makes the NSA seethe more than a trivial to analyze protocol that is secure.