Blockchain Security and Privacy Flashcards
7 cards from real CBSA practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Blockchain Security and Privacy flashcards as text
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?
Answer: Zero-knowledge proof
Zero-knowledge proofs (ZKPs) let a prover demonstrate knowledge of a secret without disclosing the secret itself, enabling privacy-preserving verification on blockchains.
In a Hyperledger Fabric network, what mechanism restricts which peers can see specific transaction data?
Answer: Private data collections
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.
An attacker intercepts a signed blockchain transaction and replays it on a different chain with the same chain parameters. Which protection prevents this?
Answer: Chain ID in transaction signing (EIP-155)
EIP-155 includes the chain ID in the transaction signature so a transaction signed for one network is cryptographically invalid on any other network.
Which consensus attack requires an adversary to control more than 50% of a proof-of-work network's hash rate?
Answer: 51% attack
A 51% attack gives the majority miner the ability to reorganize the blockchain, reverse transactions, and double-spend by outpacing honest miners.
What is the primary security risk of using a deterministic wallet (BIP-32/BIP-44) without proper key management?
Answer: Compromise of the master seed exposes all derived keys
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.
In a permissioned blockchain, which identity management model uses X.509 certificates issued by a Certificate Authority to authenticate participants?
Answer: Membership Service Provider (MSP)
Hyperledger Fabric's Membership Service Provider uses X.509 certificates from a CA to define and verify the identities of all network participants.
A smart contract stores sensitive patient records directly on a public blockchain. What is the most critical privacy violation this causes?
Answer: Data immutability makes personal data erasure impossible, violating GDPR
Immutable public blockchains conflict with the GDPR 'right to be forgotten' because personal data stored on-chain cannot be deleted once confirmed.