Cryptography
Understand encryption algorithms, protocols, PKI, hashing, and cryptographic attacks.
10 Topics
Key concepts
3 Levels
Beginner to Advanced
2 Tools
Curated for this track
8 Questions
Test yourself
About this track
The mathematics everything else quietly depends on.
Cryptography underpins every other domain in this platform, and it is the one most often used incorrectly. The practical goal of this track is not to invent ciphers — it is to know which primitive fits a problem, how implementations fail, and how to spot a broken construction in a code review.
You will work through symmetric and asymmetric primitives, hashing, and signatures, then move into the protocol layer where TLS and PKI combine them. The attack sections matter most: padding oracles, nonce reuse, and length extension teach more about a primitive than its specification does.
The recurring lesson is that cryptographic failures are almost always failures of use rather than of the underlying mathematics.
Key topics
10 topics grouped into three modules, in the order you should meet them.
- 01
Primitives
4 topics- 1.
Symmetric Encryption
AES and ChaCha20, and why the mode of operation matters more than the cipher.
- 2.
Asymmetric Encryption
RSA and elliptic curves — key exchange and encryption without a shared secret.
- 3.
Hashing Algorithms
Preimage and collision resistance, and why fast hashes are wrong for passwords.
- 4.
Digital Signatures
Authenticity and non-repudiation, plus the nonce failures that leak private keys.
- 1.
- 02
Protocols & PKI
4 topics- 5.
PKI & Certificates
Chains of trust, certificate authorities, revocation, and how it fails in practice.
- 6.
TLS/SSL
The handshake in detail — the single most important protocol on the internet.
- 7.
Cryptographic Attacks
Padding oracles, length extension, and side channels that ignore the mathematics entirely.
- 8.
Key Management
Generation, rotation, storage, and destruction — where real systems usually break.
- 5.
- 03
Attacks & frontiers
2 topics- 9.
Blockchain Basics
Merkle trees and consensus as an applied use of hashing and signatures.
- 10.
Quantum Cryptography
What Shor's algorithm actually threatens, and what post-quantum migration involves.
- 9.
What you'll be able to do
- Choose the correct primitive and mode for a given security requirement
- Recognise misuse — ECB, reused nonces, unauthenticated encryption — in a code review
- Explain how TLS and PKI establish trust, and where that trust can break
- Execute classic attacks such as padding oracles and length extension