CBSA Blockchain Security and Privacy 4 — Questions and Answers
Question 1: Which Hyperledger Fabric feature ensures that chaincode execution results are consistent across endorsing peers before being ordered?
- PBFT ordering
- Execute-Order-Validate (EOV) architecture (Correct answer)
- Raft leader election
- Gossip protocol
Correct answer: Execute-Order-Validate (EOV) architecture
Fabric's Execute-Order-Validate architecture separates endorsement from ordering, allowing parallel simulation and ensuring deterministic results are validated before block commit.
Question 2: An oracle manipulation attack on a DeFi protocol most directly exploits which weakness?
- Flawed consensus mechanism
- Reliance on a single or manipulable off-chain price feed (Correct answer)
- Overflowing integer arithmetic in smart contracts
- Insufficient gas limits
Correct answer: Reliance on a single or manipulable off-chain price feed
Oracle manipulation attacks exploit contracts that use a single manipulable price source, allowing flash-loan attackers to distort the price feed and trigger unfair liquidations or mints.
Question 3: What does 'key ceremony' refer to in blockchain PKI security?
- The process of generating genesis block keys
- A formal, witnessed procedure for generating and splitting cryptographic root keys with audit controls (Correct answer)
- Smart contract deployment to mainnet
- The onboarding ritual for new validator nodes
Correct answer: A formal, witnessed procedure for generating and splitting cryptographic root keys with audit controls
A key ceremony is a structured, multi-party event where root CA or master keys are generated with witnesses, HSMs, and documented procedures to prevent any single party from obtaining full control.
Question 4: Which attack targets the peer-to-peer network layer of a blockchain node by surrounding it with malicious peers to control all its inbound and outbound connections?
- Man-in-the-middle attack
- Eclipse attack (Correct answer)
- Selfish mining
- Transaction flooding
Correct answer: Eclipse attack
An eclipse attack isolates a target node by filling all its peer connection slots with adversary-controlled nodes, enabling double-spend attacks or denying it access to the honest chain.
Question 5: In the context of blockchain cryptography, what is a 'nonce' primarily used for in proof-of-work mining?
- Identifying the miner's wallet address
- An arbitrary number miners iterate to find a hash meeting the difficulty target (Correct answer)
- Encrypting the block header
- Signing the coinbase transaction
Correct answer: An arbitrary number miners iterate to find a hash meeting the difficulty target
Miners repeatedly change the nonce value in a block header and rehash until the resulting hash falls below the network's difficulty target, proving computational work.
Question 6: Which GDPR principle conflicts most directly with blockchain's core immutability property?
- Data minimization
- Right to erasure (right to be forgotten) (Correct answer)
- Purpose limitation
- Lawful basis for processing
Correct answer: Right to erasure (right to be forgotten)
GDPR's right to erasure requires that personal data be deleted upon request, which is fundamentally incompatible with a blockchain's append-only, tamper-evident ledger design.
Question 7: What is the role of a Hardware Security Module (HSM) in a blockchain deployment?
- Accelerating consensus algorithm computation
- Securely generating, storing, and using cryptographic keys in tamper-resistant hardware (Correct answer)
- Providing off-chain data feeds to smart contracts
- Running smart contract bytecode in an isolated environment
Correct answer: Securely generating, storing, and using cryptographic keys in tamper-resistant hardware
An HSM is a dedicated hardware device that keeps private keys inside a tamper-resistant boundary, performing cryptographic operations without ever exposing the raw key material.
CBSA Blockchain Security and Privacy 4
Which Hyperledger Fabric feature ensures that chaincode execution results are consistent across endorsing peers before being ordered?