CBSA - Certified Blockchain Solution Architect Blockchain Security and Privacy Questions and Answers

Question 1

A blockchain solution for a consortium of banks requires that the details of a transaction (sender, receiver, amount) be verifiable by network participants without revealing the actual information to the public.
Which cryptographic method is MOST suitable for achieving this specific privacy requirement?

Accepted Answer

Zero-Knowledge Proofs (ZKPs)

Answer

Homomorphic Encryption

Answer

Ring Signatures

Answer

Public-Key Cryptography

Question 2

A solution architect is designing a decentralized application on a public blockchain where a smart contract handles financial agreements. A critical security concern is preventing an attacker from repeatedly calling a withdrawal function before the contract's state (e.g., the user's balance) is updated. Which of the following vulnerabilities does this scenario describe?

Accepted Answer

Reentrancy Attack

Answer

Integer Overflow

Answer

Timestamp Dependence

Answer

Unchecked External Call

Question 3

Which of the following represents the most significant threat to the integrity of a Proof-of-Work (PoW) blockchain, where a single entity or group could potentially reverse transactions and prevent new ones from being confirmed?

Accepted Answer

51% Attack

Answer

Sybil Attack

Answer

Denial-of-Service (DoS) Attack

Answer

Eclipse Attack

Question 4

When architecting a private, permissioned blockchain solution for supply chain management, what is the most effective initial measure to prevent unauthorized organizations from joining the network and accessing sensitive data?

Accepted Answer

Establishing a robust Identity and Access Management (IAM) framework.

Answer

Implementing Zero-Knowledge Proofs for all transactions.

Answer

Enforcing strict on-chain governance rules.

Answer

Encrypting all data stored on the ledger.

Question 5

A developer writes a smart contract function that sends Ether to an external address. The code proceeds with updating internal state variables immediately after the `send()` or `transfer()` call, without checking if the call was successful. This practice makes the contract vulnerable to which type of attack?

Accepted Answer

Unchecked External Calls

Answer

Reentrancy

Answer

Access Control Vulnerabilities

Answer

Integer Underflow

Question 6

A solution architect is evaluating privacy-enhancing technologies. One option involves a cryptographic signature scheme where a transaction can be signed by one member of a group, but an external observer can only verify that the signature came from the group, not which specific member signed it. What is this technology called?

Accepted Answer

Ring Signatures

Answer

Stealth Addresses

Answer

Confidential Transactions

Answer

Shamir's Secret Sharing