Web3 Entrepreneurship · MBA Programme Zishan A. Mohammad · March 2026
Consensus Mechanism Matrix
99.95%
Ethereum's energy reduction after The Merge, September 2022
Chapter Thesis
Every blockchain design choice is a deliberate trade-off between decentralisation, security, and throughput — there is no free lunch.
Chapter 2 of 8 · Protocol Design
Key Takeaways
1
Proof of Work secures via economic cost of attack; Proof of Stake secures via economic cost of slashing. PoS achieves comparable security at 99.95% lower energy cost.
2
Solana's design deliberately trades some decentralisation for throughput (50,000 TPS theoretical). This is not a flaw — it is an explicit, well-reasoned design choice with known trade-offs.
3
No blockchain has solved the trilemma. Layer 2 solutions (Optimism, Arbitrum, zkSync) scale Ethereum by moving computation off-chain while inheriting L1 security.
Glossary
Proof of Stake (PoS)
Consensus where validators are selected proportional to staked collateral; slashing punishes misbehaviour; used by Ethereum post-Merge.
Finality
The point at which a transaction is considered irreversible; probabilistic in PoW (6 confirmations ≈ safe), deterministic in most PoS systems.
MEV (Maximal Extractable Value)
Profit validators extract by reordering, inserting, or censoring transactions within a block; a structural feature of transparent mempools.
60% Test
Compare Ethereum and Solana architectural trade-offs. What changed at The Merge and why? How do Layer 2s scale without sacrificing security?