CBSA Blockchain Security and Privacy 2

Question 1

Which cryptographic technique allows a prover to convince a verifier that a statement is true without revealing any information beyond the validity of the statement?

Accepted Answer

Zero-knowledge proof

Answer

Zero-knowledge proofs (ZKPs) let a prover demonstrate knowledge of a secret without disclosing the secret itself, enabling privacy-preserving verification on blockchains.

Question 2

In a Hyperledger Fabric network, what mechanism restricts which peers can see specific transaction data?

Accepted Answer

Private data collections

Answer

Private data collections in Hyperledger Fabric allow only authorized peers to access the actual data while the hash of the data is recorded on the main ledger.

Question 3

An attacker intercepts a signed blockchain transaction and replays it on a different chain with the same chain parameters. Which protection prevents this?

Accepted Answer

Chain ID in transaction signing (EIP-155)

Answer

EIP-155 includes the chain ID in the transaction signature so a transaction signed for one network is cryptographically invalid on any other network.

Question 4

Which consensus attack requires an adversary to control more than 50% of a proof-of-work network's hash rate?

Accepted Answer

51% attack

Answer

A 51% attack gives the majority miner the ability to reorganize the blockchain, reverse transactions, and double-spend by outpacing honest miners.

Question 5

What is the primary security risk of using a deterministic wallet (BIP-32/BIP-44) without proper key management?

Accepted Answer

Compromise of the master seed exposes all derived keys

Answer

Because all child keys are deterministically derived from the master seed, an attacker who obtains the seed can regenerate every private key in the wallet hierarchy.

(CBSA) Certified Blockchain Solution Architect Practice Test

(CBSA) Certified Blockchain Solution Architect Practice Test

CBSA Blockchain Security and Privacy 2