I am trying to encrypt and decrypt a file just for fun. For now I'm using Base64 but I want to do it using a passphrase. I would appreciate if there was some way of doing that manually without using so many already-made classes. I like to make my own.
SOLUTION: As suggested by @ThomasEdwin, I've checked Jasypt and it is really useful, I will play with the tools a little and then figure out what I'm gonna do using the source code. Thank you all for the help.