Applied Cryptography: How It Works and Breaks
Encoding, hashing, XOR, symmetric and asymmetric crypto — understand each one and why weak keys and passwords undo it, on your own data.
One-time payment · lifetime access · lessons, labs, exam and certificate included · no subscription.
About this course
This course makes cryptography concrete by having you build and then break your own small examples. You start by separating encoding, hashing and encryption, then round-trip Base64 and hex to prove they offer no secrecy. You decode ROT13 and Caesar ciphers, XOR-encrypt a phrase with a single byte and brute-force all 256 keys, and watch an unsalted MD5 password fall to a tiny wordlist. You encrypt a file with AES using openssl and see how a cracked password unravels it, then build intuition for RSA public and private keys and their role in TLS and SSH. Throughout, the lesson is clear: strong algorithms are undone by weak keys. Every artifact is created and analysed on your own machine, for authorized learning only.
Lessons
- Encoding ≠ Encryption ≠ Hashing Pro
- Encoding — Base64 & Hex Pro
- Classical Ciphers — ROT13 & Caesar Pro
- XOR — the Heart of Symmetric Crypto Pro
- Hashing — One-Way, But Not Always Safe Pro
- Symmetric Encryption — AES with openssl Pro
- Asymmetric Crypto & TLS (Intuition) Pro
- Final Exam — Work Through Your Own Artifacts Pro