Crypto? Never roll your own. Author’s note: The purpose of this post is to provide an introduction to cryptography, ciphers, and encoding techniques commonly used in capture the flag (CTF) challenges. It’s the resource I would have wanted when I was approaching my first CTF cryptography challenges! I provide examples of ciphertext (or encoded text) to help the build intuition that will help with cipher recognition! In my opinion, that’s the hardest part of solving CTF crypto challenges!