Cryptography for authentication and encryption is a complex and frequently changing field, and for somebody new to using it, it can be hard to know where to start. If you’re a GNU/Linux user comfortable with the terminal, but unfamiliar with the cryptographic tools available to you on open source UNIX-like operating systems, this series of posts aims at getting you set up with some basic tools that will allow you to keep your own information secure, to authenticate conveniently and safely with remote servers, and to work with signed and encrypted files online.