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Question 1. Which characteristic distinguishes a permissioned blockchain from a permissionless one? A) Use of proof‑of‑work consensus B) Open participation for any node C) Controlled access via identity management D) Native cryptocurrency token Answer: C Explanation: Permissioned blockchains restrict participation to known, vetted identities, unlike permissionless networks that allow anyone to join. Question 2. In Hyperledger Fabric, which peer type is responsible for simulating transaction proposals and generating endorsement signatures? A) Anchor peer B) Endorsing peer C) Committing peer D) Ordering peer Answer: B Explanation: Endorsing peers execute the chaincode simulation and produce cryptographic endorsements required for transaction validation. Question 3. What is the primary function of the Ordering Service in Fabric? A) Store world‑state data B) Validate endorsement policies C) Establish total order of transactions across the channel D) Manage user certificates Answer: C
Explanation: The Ordering Service collects endorsed transactions, orders them into blocks, and disseminates them to committing peers. Question 4. Which consensus algorithm is NOT natively supported by Fabric’s ordering service? A) Raft B) Kafka C) Solo D) PBFT Answer: D Explanation: Fabric provides Solo, Kafka, and Raft ordering; PBFT is not a built‑in ordering consensus for Fabric. Question 5. In a Fabric channel, what does an anchor peer provide? A) Transaction endorsement capability B) A discovery point for cross‑channel communication C) A permanent ledger backup D) A trusted time source for ordering Answer: B Explanation: Anchor peers are advertised in channel configuration to enable other organizations to locate peers for inter‑organization gossip. Question 6. Which component issues X.509 certificates to users and applications in a Fabric network? A) Membership Service Provider (MSP) B) Certificate Authority (CA) C) Ordering Service
B) CouchDB C) MySQL D) PostgreSQL Answer: B Explanation: CouchDB stores world‑state as JSON documents, allowing complex queries via Mango selectors. Question 10. What is the purpose of the “private data collection” feature in Fabric? A) To store encrypted ledger on the ordering service B) To keep confidential data off‑chain while still providing hash‑based verification on the main ledger C) To replicate world state across all peers in the network D) To enable anonymous transaction endorsement Answer: B Explanation: Private data collections allow organizations to share sensitive data privately; only the hash of the private data is written to the public ledger. Question 11. Which command sequence correctly installs a chaincode on a peer using the Fabric CLI? A) peer lifecycle chaincode approveformyorg → peer lifecycle chaincode install B) peer lifecycle chaincode package → peer lifecycle chaincode install C) peer chaincode instantiate → peer chaincode invoke D) peer channel join → peer lifecycle chaincode commit Answer: B Explanation: The typical lifecycle starts with packaging the chaincode, then installing the package on peers.
Question 12. In Fabric chaincode, which API call retrieves the complete history of a key’s values? A) GetState B) PutState C) GetHistoryForKey D) DelState Answer: C Explanation: GetHistoryForKey returns an iterator over all historical values and timestamps for a specific key. Question 13. Which endorsement policy would require at least one peer from Org1 and one peer from Org2 to endorse a transaction? A) "OR('Org1.member','Org2.member')" B) "AND('Org1.member','Org2.member')" C) "OutOf(2,'Org1.member','Org2.member')" D) "Majority('Org1.member','Org2.member')" Answer: B Explanation: The AND policy mandates that both organizations provide at least one endorsement each. Question 14. What is the primary advantage of using the MockStub in chaincode unit testing? A) It simulates the full peer network topology B) It provides a lightweight in‑memory ledger for rapid test execution C) It automatically generates endorsement policies D) It encrypts test data for security compliance Answer: B Explanation: MockStub mimics the ledger APIs without requiring a live Fabric network, enabling fast isolated tests.
Explanation: The IntegerKey family provides a straightforward key/value store for integer values. Question 18. What is the core idea behind Sawtooth’s PoET consensus algorithm? A) Nodes solve cryptographic puzzles B) Nodes wait a randomly assigned time in a trusted execution environment (TEE) C) Nodes vote on blocks using Byzantine fault tolerance D) Nodes stake cryptocurrency to become validators Answer: B Explanation: PoET leverages TEEs to generate a verifiable waiting period, ensuring fairness without intensive computation. Question 19. Which consensus protocol used in Sawtooth provides deterministic finality and tolerates up to ⅓ Byzantine nodes? A) Raft B) PoET C) PBFT D) Tendermint Answer: C Explanation: Practical Byzantine Fault Tolerance (PBFT) achieves finality with up to one‑third malicious nodes. Question 20. How does Sawtooth achieve higher throughput compared to serial execution models? A) By using sharding across multiple ledgers B) By executing non‑conflicting transactions in parallel C) By compressing blocks before broadcasting D) By delegating consensus to external services
Answer: B Explanation: Sawtooth’s parallel transaction execution allows independent transactions to be processed simultaneously, boosting throughput. Question 21. In Hyperledger Indy, what does a DID (Decentralized Identifier) consist of? A) A public key only B) A URI pointing to a blockchain transaction C) A method identifier, a unique namespace, and a unique identifier string D) An encrypted credential payload Answer: C Explanation: A DID follows the format did:<method>:<specific‑id> and is resolvable to a DID Document containing public keys and service endpoints. Question 22. Which component in Indy is responsible for issuing and revoking verifiable credentials? A) Ledger B) Wallet C) Issuer D) Verifier Answer: C Explanation: The Issuer creates credentials, signs them with its private key, and can later revoke them via the ledger. Question 23. What is a zero‑knowledge proof (ZKP) used for in SSI systems? A) Encrypting the credential data at rest B) Proving possession of a credential attribute without revealing the attribute itself
A) To provide a set of reusable, vetted cryptographic primitives across projects B) To store private keys in a distributed ledger C) To replace the need for X.509 certificates D) To manage consensus algorithms for Hyperledger Sawtooth Answer: A Explanation: Ursa supplies common, audited implementations of signatures, zero‑knowledge proofs, and other crypto functions for Indy and Aries. Question 27. Which client type does Hyperledger Besu implement to interact with the Ethereum network? A) Light client only B) Full node supporting both PoW and PoA consensus C) Miner node exclusive to private networks D) Oracle node for external data feeds Answer: B Explanation: Besu can run as a full Ethereum client and supports Proof‑of‑Work (Ethash) as well as Proof‑of‑Authority (IBFT 2.0, Clique). Question 28. Which consensus algorithm is used by Besu in a permissioned consortium network with known validators? A) Ethash B) Proof of Stake (Casper) C) IBFT 2. D) Raft Answer: C Explanation: IBFT 2.0 (Istanbul BFT) provides fast finality and is designed for permissioned Ethereum networks.
Question 29. What is the primary function of the Orion/Tessera privacy manager in Besu? A) To encrypt the entire blockchain state B) To enable private transactions by storing payloads off‑chain and sharing only hashes on the public chain C) To manage node identities via X.509 certificates D) To provide a REST API for smart contract deployment Answer: B Explanation: Orion/Tessera acts as a transaction manager that holds private payloads securely while the public chain only records a reference. Question 30. How does Besu enforce node‑level permissioning in a consortium setting? A) By requiring a proof‑of‑work solution from each node B) Through a whitelist/blacklist stored on‑chain that the client checks before accepting connections C) By using TLS mutual authentication only D) By limiting the number of transactions per node per block Answer: B Explanation: Besu supports on‑chain permissioning contracts that maintain lists of allowed or denied node IDs. Question 31. Which tool provides a graphical web interface to explore blocks, transactions, and chaincode events in a Fabric network? A) Hyperledger Caliper B) Hyperledger Explorer C) Hyperledger Cello D) Hyperledger Firefly
C) To replace the ordering service in Fabric D) To act as a private data store for Sawtooth Answer: B Explanation: Firefly aggregates connectivity, identity, and data handling across different DLTs, simplifying multi‑ledger app development. Question 35. In a supply‑chain solution using Fabric, which feature ensures that a retailer can view only the transactions relevant to its purchases while other participants cannot see them? A) Private data collections B) Public ledger with encryption C) Separate channels for each participant D) Chaincode that filters data on the client side Answer: A Explanation: Private data collections allow a subset of organizations to share confidential transaction details without exposing them to the entire channel. Question 36. When designing a CBDC (Central Bank Digital Currency) platform, which Hyperledger project would be most suitable for handling high‑throughput, public‑ledger requirements while retaining permissioned control? A) Hyperledger Sawtooth B) Hyperledger Besu C) Hyperledger Indy D) Hyperledger Fabric Answer: B Explanation: Besu offers Ethereum compatibility, enabling smart contracts and public‑ledger features while supporting permissioned consensus (IBFT) for central bank control.
Question 37. Which design pattern recommends using multiple channels versus private data collections for data isolation? A) “Channel per asset class” pattern – multiple channels are preferred when organizational boundaries are strict and policies differ significantly. B) “Single channel with ACLs” pattern – private collections are unnecessary. C) “Hybrid” pattern – combine channels for governance and private collections for confidential data. D) “No isolation” pattern – store all data openly. Answer: C Explanation: A hybrid approach leverages channels for overall governance while private collections protect sensitive fields within the same channel. Question 38. In a healthcare use‑case, which Hyperledger technology best supports patient‑controlled verifiable credentials for sharing medical records? A) Fabric chaincode B) Indy/Aries SSI stack C) Sawtooth transaction families D) Besu smart contracts Answer: B Explanation: Indy/Aries enable self‑sovereign identity, allowing patients to hold and present verifiable credentials securely. Question 39. What is the lifecycle stage of a Hyperledger project that is still under active development but not yet recommended for production use? A) Incubation B) Active C) Deprecated D) End‑of‑Life
C) "OutOf(2,'Org1.peer0','Org1.peer1','Org1.peer2')" D) "Majority('Org1.peer0','Org1.peer1','Org1.peer2')" Answer: C Explanation: OutOf(2, …) means any two of the listed identities must provide endorsements. Question 43. Which Fabric component validates that a transaction’s read‑write set has not been invalidated by concurrent updates? A) Endorser B) Orderer C) Committer (validation phase) D) MSP Answer: C Explanation: During validation, the committing peer checks version numbers of keys in the read‑set against the current world state. Question 44. What is the default state database for a newly created Fabric network if no explicit choice is made? A) CouchDB B) LevelDB C) SQLite D) MySQL Answer: B Explanation: LevelDB is the embedded key‑value store used by default for the world state. Question 45. In Sawtooth, which component is responsible for maintaining the global Merkle‑based state tree?
A) Transaction Processor B) Validator C) Consensus Engine D) REST API Answer: B Explanation: Validators store and update the Merkle state tree as they apply transaction results. Question 46. Which Sawtooth consensus algorithm relies on Intel SGX to guarantee that the waiting time is not tampered with? A) PoET B) PBFT C) Raft D) Proof of Work Answer: A Explanation: PoET uses SGX enclaves to produce a verifiable random wait time, ensuring fairness. Question 47. In a Hyperledger Indy ledger, what type of transaction records a new DID document? A) NYM transaction B) ATTRIB transaction C) SCHEMA transaction D) CRED_DEF transaction Answer: A Explanation: NYM transactions add or update DID entries on the ledger. Question 48. Which Aries protocol is used to request a verifiable credential from an issuer?
Question 51. In Hyperledger Explorer, which of the following can NOT be directly visualized? A) Block details B) Chaincode source code C) Transaction payloads D) Peer status Answer: B Explanation: Explorer shows ledger data but does not display the actual source code of deployed chaincode. Question 52. Which metric is NOT typically reported by Hyperledger Caliper after a benchmark run? A) Average transaction latency B) Peak CPU usage of peers C) Transaction success rate D) Ledger size growth per block Answer: D Explanation: Caliper focuses on performance metrics; ledger size growth is not a standard output. Question 53. When using Cello to deploy a Fabric network on Kubernetes, which component defines the network topology (organizations, peers, orderers)? A) Helm chart values file B) Docker‑compose file C) Cello “Blueprint” JSON D) Fabric‑CA configuration file Answer: C
Explanation: Cello blueprints describe the desired network structure and are used to generate deployment manifests. Question 54. Which Hyperledger tool provides a “smart contract repository” and CI/CD pipelines for chaincode development? A) Hyperledger Composer (now deprecated) B) Hyperledger Firefly C) Hyperledger Fabric SDK D) Hyperledger Burrow Answer: B Explanation: Firefly includes capabilities for managing contract lifecycles, versioning, and automated deployment. Question 55. In a multi‑ledger application, which Hyperledger project assists in routing transactions to the appropriate underlying DLT based on business rules? A) Explorer B) Caliper C) Firefly D) Cello Answer: C Explanation: Firefly’s “connector” architecture abstracts multiple ledgers and routes calls according to configuration. Question 56. Which consensus algorithm used by Fabric’s Raft ordering service is a leader‑based protocol that provides crash fault tolerance? A) PBFT B) Raft
