Key Takeaways
1
Blockchain removes trusted intermediaries by replacing them with cryptographic consensus — but this creates a trilemma: no network can simultaneously maximise decentralisation, security, and scalability.
2
Three generations of blockchain: Bitcoin (store of value / PoW), Ethereum (smart contract platform / PoS), Layer 2s (scalability solutions built on Ethereum).
3
Web3 is the application layer built on blockchain: ownership of digital assets, programmable money, and self-sovereign identity — contrasted with Web2's platform-mediated ownership.
Glossary
Proof of Work
Consensus mechanism where miners compete to solve computational puzzles; energy-intensive; used by Bitcoin. Security through economic cost of attack.
Smart Contract
Self-executing code stored on-chain that runs automatically when pre-defined conditions are met — the foundation of DeFi and Web3 applications.
Layer 2
A scaling solution built on top of a base blockchain (L1) that processes transactions off-chain and settles proofs on-chain; e.g. Optimism, Arbitrum, zkSync.