Crypto Ch4: Design Space
Chapter 4. The blockchain design space
4.1 Why chains look so different
All chains try to balance difficult trade-offs:
- Security
- Decentralization
- Throughput
- Low latency
- Low cost
- Verifiability
- Ease of development
These goals conflict. Different chains prioritize different parts of the design space.
A chain is therefore best understood not as a universal answer, but as a chosen point in a constrained design space.
4.2 UTXO vs account
UTXO
- Object-like spendable outputs
- Clean validation logic
- Good for money-like transfer systems
- Less intuitive for applications
Account
- Mutable global state
- Easier for smart contracts and rich stateful applications
- More intuitive for users
- Harder to control state growth and coordination complexity
This is not just a syntax difference. It shapes the type of applications that fit naturally on a system.
4.3 PoW vs PoS
Proof of Work
Security is anchored in external physical cost: hardware, energy, and operational expenditure.
Proof of Stake
Security is anchored in internal economic stake: locked capital, validator behavior, and slashing risk.
This is the most important difference:
- PoW constrains attackers through external physical cost
- PoS constrains attackers through internal economic penalty and stake alignment
4.4 Finality intuition
PoW systems
Finality is usually probabilistic and improves with more confirmations.
Proof of Stake systems
Finality is often more explicit, based on validator votes reaching protocol-defined thresholds.
4.5 PoH in context
Proof of History (PoH), associated with Solana, is best understood as a verifiable ordering/time mechanism, not a complete stand-alone consensus system. It helps the network maintain an ordered progression of events more efficiently.
It is useful to think of PoH as a way to create a verifiable sequencing clock, which can help a high-performance system reduce some coordination overhead.
4.6 Monolithic vs modular design
Monolithic chains
Execution, consensus, settlement, and data availability are all handled on the base chain.
Modular / layered systems
Different layers specialize:
- One layer may provide security and settlement
- Another may provide execution
- Another may provide data availability
This is the logic behind L2 ecosystems.
4.7 L1 vs L2
L1
The base chain: final security and settlement layer.
L2
A secondary execution environment that relies on an L1 for final settlement and security assumptions.
The core distinction is not merely “fast versus slow.” It is about where execution happens and where final trust is anchored.
4.8 Three major architectural styles
Bitcoin
Prioritizes decentralized settlement and monetary stability.
Ethereum
Prioritizes programmability and protocol composability, while increasingly relying on L2s for execution scale.
Solana
Prioritizes high-performance execution directly on the L1, with different trade-offs in hardware demands and system complexity.
4.9 A general evaluation template for chains
When evaluating a chain, ask:
- What problem is it trying to solve?
- What is its state model?
- What is its consensus mechanism?
- What does it place on the base layer vs other layers?
- Why is it fast?
- Why is it cheap?
- Where is the centralization pressure?
- How is the token tied to the protocol?
Key takeaway
Blockchains are best understood as trade-off machines. Asking “what did this chain optimize for, and what did it sacrifice?” is more useful than asking “which chain is best?”
— Mar 23, 2026
Crypto Ch4: Design Space by Lu Meng is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License. Permissions beyond the scope of this license may be available at About.
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