Blockchain Security
Attack vectors, vulnerabilities, and defenses
The adversarial view: 51% attacks, Sybil attacks, smart contract exploits (reentrancy, integer overflow), MEV, private key security, and how to think like an attacker to build better defenses.
Lessons
51% Attacks and Chain Reorganization
How majority hash rate enables double-spends and what happened to Ethereum Classic.
Sybil and Eclipse Attacks
Manipulating P2P network topology to isolate and deceive nodes.
Smart Contract Vulnerabilities
Reentrancy (the DAO hack), integer overflow, access control, and static analysis.
MEV and Frontrunning
Maximal extractable value, sandwich attacks, and flashbots.
Private Key Security and OpSec
Hardware wallets, air gaps, seed phrase storage, and how people actually lose crypto.
What you'll be able to do
- Analyze real blockchain attacks and understand what made them possible
- Identify common smart contract vulnerability patterns
- Explain MEV and its impact on transaction ordering
- Apply best practices for private key security
Module exam
Blockchain Security Exam
3 questions · Pass to earn your certificate
Complete all lessons before taking the exam.