With the recent personal data leaks regarding celebrities, I noticed that I’ve some data on my cloud storage which should have an extra layer of protection. And NO, I don’t have any private pictures, but a document or two with some very sensitive data. You never know when you might be a victim of phishing or from a weak password. In any case, I decided to investigate some encryption algorithms. More precisely, XOR cipher, Feistel cipher and blowfish. In this article I’ll try to give some guidelines regarding these ciphers and example implementation in C++ with Qt. This article should be structured and written in a way, if you don’t know anything about cryptography, at the end you should understand most of the basic underlying theories. Also each algorithm will be introduced in a sequence where the next algorithm described will reference to previous one. Note that the intention of this article is to explain how to use them, rather than analyze their security etc.