Malexandre
Trying to use a library to encrypt your data can be a lot to handle when you have no experience or knowledge about their inner workings. There is more than just selecting a cipher algorithm like Blowfish or AES. You also have to chose a mode, manage an initialization vector, and sometimes even more. As a memento, but also to help others, I will try to explain some of those concepts, and how to use them with PyCrypto, the main encryption library in Python.
AES