CBSA Blockchain Architecture & Design Principles 2

Question 1

Which architectural pattern allows off-chain computations to be verified on-chain without re-executing them?

Accepted Answer

Zero-knowledge proofs

Answer

Zero-knowledge proofs let a prover convince a verifier that a computation is correct without revealing inputs or re-running it on-chain.

Question 2

In a UTXO-based blockchain model, what does a transaction consume?

Accepted Answer

Previous unspent transaction outputs

Answer

UTXO (Unspent Transaction Output) models require transactions to spend existing outputs and create new ones, unlike account-based models.

Question 3

What is the primary role of a mempool in blockchain architecture?

Accepted Answer

Holding unconfirmed transactions awaiting inclusion

Answer

The mempool (memory pool) is a node's local buffer of broadcast transactions not yet included in a block.

Question 4

Which design approach best addresses the blockchain trilemma by sacrificing some decentralization for scalability?

Accepted Answer

Delegated Proof of Stake

Answer

DPoS concentrates validation among elected delegates, improving throughput and finality at the cost of reduced decentralization.

Question 5

When designing a multi-chain architecture, what purpose does a relay chain serve?

Accepted Answer

Providing shared security and cross-chain message passing

Answer

A relay chain (as in Polkadot) coordinates consensus and provides shared security so individual parachains don't need their own validator sets.

(CBSA) Certified Blockchain Solution Architect Practice Test