CBSE Enterprise Blockchain Security 2 — Questions and Answers
Question 1: Which consensus mechanism is most susceptible to a Sybil attack in an enterprise permissioned blockchain?
- Proof of Authority (PoA)
- Delegated Proof of Stake (DPoS)
- Proof of Work (PoW) (Correct answer)
- Practical Byzantine Fault Tolerance (PBFT)
Correct answer: Proof of Work (PoW)
Proof of Work is vulnerable to Sybil attacks because an attacker can create many identities and accumulate hashing power without a trusted identity layer.
Question 2: In an enterprise Hyperledger Fabric deployment, what is the primary role of the Membership Service Provider (MSP)?
- Encrypting chaincode execution
- Managing digital identities and access control (Correct answer)
- Distributing ledger data across peers
- Monitoring transaction throughput
Correct answer: Managing digital identities and access control
The MSP defines the rules for validating identities and governs which participants are allowed to perform specific actions on the network.
Question 3: A company suspects that a rogue peer is endorsing fraudulent transactions. Which Hyperledger Fabric feature helps detect this?
- Gossip protocol
- Endorsement policy validation at commit time (Correct answer)
- CouchDB state database
- Kafka ordering service
Correct answer: Endorsement policy validation at commit time
Endorsement policies are re-validated by committing peers, so transactions endorsed by unauthorized nodes are rejected at commit time.
Question 4: What threat does 'transaction malleability' pose in enterprise blockchain environments?
- Leaking private keys stored in hardware wallets
- Altering a transaction's unique identifier before it is confirmed (Correct answer)
- Overwriting smart contract bytecode in the EVM
- Preventing nodes from reaching quorum
Correct answer: Altering a transaction's unique identifier before it is confirmed
Transaction malleability allows an attacker to change a transaction's hash before confirmation, potentially enabling double-spend or replay attacks.
Question 5: Which approach best mitigates the risk of sensitive data exposure on a public blockchain used for enterprise supply chain?
- Storing all data on-chain with AES-256 encryption
- Using zero-knowledge proofs to verify data without revealing it (Correct answer)
- Relying on network obscurity by using a private RPC endpoint
- Compressing data with gzip before submission
Correct answer: Using zero-knowledge proofs to verify data without revealing it
Zero-knowledge proofs allow enterprises to prove the validity of a claim without exposing the underlying data on the public ledger.
Question 6: An enterprise blockchain network experiences a 51% attack scenario in its proof-of-stake system. What is the correct term for the minimum stake an attacker must control?
- 33% of total staked tokens
- 51% of total staked tokens (Correct answer)
- 67% of total staked tokens
- 100% of circulating supply
Correct answer: 51% of total staked tokens
In PoS, controlling more than 50% of staked tokens gives an attacker the ability to dominate block production and potentially reorganize the chain.
Question 7: Which security layer is most critical to configure when exposing a Hyperledger Fabric peer node to external enterprise applications?
- CORS headers on the REST API
- Mutual TLS (mTLS) for gRPC communication (Correct answer)
- HTTP Basic Authentication on the admin console
- Firewall rules blocking UDP traffic
Correct answer: Mutual TLS (mTLS) for gRPC communication
Mutual TLS ensures both the client and server authenticate each other's certificates, preventing unauthorized connections to fabric peer endpoints.
CBSE Enterprise Blockchain Security 2
Which consensus mechanism is most susceptible to a Sybil attack in an enterprise permissioned blockchain?