How to Get Started with Cryptography
There are 2 things you need to do:
Solve puzzles
Learn some theory
Puzzles (free):
- Server puzzles: https://decipher.wiki/puzzles
- DECIPHER Academy: https://decipher.wiki/academy
- ae27ff – 42 levels (I'm at level 31!)
- NotPron – 140 levels (I'm at level 23!)
- Gamedetective's The Academy – basic ciphers, computing, stego, etc.
- CryptoHack – modern challenges with free courses
- stillaplanet – cryptic programming + lore
Theory:
Start by learning Caesar Cipher and Vigenère Cipher. Try watching tutorials on YouTube. Tools that help:
Offline Learning Resources
Books:
- Methods for the solution of running-key ciphers (Friedman)
- Military Cryptanalysis (Friedman)
- Elementary cryptanalysis by Sinkov
- A Book on Classical Cryptography by Madness (GCHQ)
- A methodology for the cryptanalysis of classical ciphers with search metaheuristics by Lasry
- Solving Cipher Problems by Lewis
- Decrypted Secrets by Bauer
- Cryptanalysis by Gaines
Online Learning Resources
Websites:
- DECIPHER website
- Cipher types
- Practical Cryptography
- Bion's Gadgets – cipher tools
- Bion's Spot – help resources
- Cryptogram help
- Where to start – Reddit guide
- Two crash course websites: TheAcademy and CryptoHack