Download Exam Developer Hyperledger Fabric Certified Practitioner Practice Exam and more Exams Technology in PDF only on Docsity!
Certified Practitioner Practice Exam
Question 1. Which characteristic most clearly distinguishes a permissioned blockchain from a permissionless blockchain? A) Use of proof‑of‑work consensus B) Publicly readable transaction history C) Identity verification through a Membership Service Provider (MSP) D) Mining rewards paid in cryptocurrency Answer: C Explanation: Permissioned blockchains require participants to be identified and authenticated, typically via an MSP, whereas permissionless blockchains allow anonymous participation.
Question 2. In Hyperledger Fabric, what is the primary purpose of a channel? A) To increase transaction throughput by parallel processing B) To isolate ledger data among a subset of network members for privacy C) To replace the ordering service for small networks D) To provide a public API for external applications Answer: B Explanation: Channels create separate ledgers that are only visible to the organizations that join them, ensuring data confidentiality.
Certified Practitioner Practice Exam
Question 3. Which component is responsible for ordering transactions into a deterministic block sequence? A) Endorsing peer B) Ordering service node (OSN) C) Certificate Authority (CA) D) Anchor peer Answer: B Explanation: The ordering service receives endorsed transactions and batches them into blocks, establishing a total order for all peers.
Question 4. What does the Execute‑Order‑Validate model in Fabric achieve? A) Eliminates the need for consensus altogether B) Allows transaction execution before consensus, improving latency C) Guarantees that every transaction is executed on every peer D) Merges endorsement and commitment steps into a single phase Answer: B Explanation: Transactions are simulated (executed) on endorsing peers first, then ordered, and finally validated, reducing the time spent in consensus.
Certified Practitioner Practice Exam
Question 7. In Fabric’s Membership Service Provider (MSP), what is the purpose of an intermediate CA? A) To issue certificates directly to end‑users without a root CA B) To act as a backup for the ordering service C) To delegate certificate issuance from the root CA, enabling hierarchical trust D) To store the ledger’s world state Answer: C Explanation: Intermediate CAs allow the root CA to delegate signing authority, creating a scalable trust hierarchy.
Question 8. Which of the following statements about the world state in Fabric is true? A) It is stored as a blockchain of immutable blocks only B) LevelDB supports rich JSON queries out‑of‑the‑box C) CouchDB enables complex queries using JSON selectors D) The world state cannot be queried directly by chaincode Answer: C Explanation: CouchDB stores the world state as JSON documents and supports rich queries via selectors, whereas LevelDB is a simple key‑value store.
Question 9. During the proposal stage, what does a client receive from an endorsing peer?
Certified Practitioner Practice Exam
A) A signed transaction ready for ordering B) A write‑set only, without any read‑set C) An endorsement (signature) plus the read‑set and write‑set (RW set) D) The final block containing the transaction Answer: C Explanation: The endorsing peer simulates the transaction, producing an RW set and signs it, returning both to the client.
Question 10. What is the main function of the validation phase on committing peers? A) To execute chaincode again for double‑checking results B) To verify that the endorsement policy is satisfied and that MVCC conflicts do not exist C) To encrypt the transaction before committing to the ledger D) To reorder transactions based on timestamps Answer: B Explanation: Validation ensures the transaction meets the required endorsements and that the state has not changed since endorsement (MVCC check).
Question 11. Which command is used to generate the genesis block for a new channel in Fabric? A) peer channel create
Certified Practitioner Practice Exam
C) Minimum Viable Crypto Currency; it defines the native token of Fabric D) Managed Virtual Container Cluster; it orchestrates Docker containers Answer: A Explanation: MVCC (Multi‑Version Concurrency Control) checks that the state read during endorsement has not been altered before committing, preventing stale writes.
Question 14. Which of the following is NOT a valid endorsement policy language element? A) “AND('Org1.member','Org2.member')” B) “OR('Org3.admin')” C) “OutOf(2,'Org1.member','Org2.member','Org3.member')” D) “NOT('Org4.member')” Answer: D Explanation: Fabric endorsement policies support AND, OR, and OutOf; there is no NOT operator.
Question 15. In the chaincode lifecycle (Fabric v2.x), what is the purpose of the “ApproveForMyOrg” transaction? A) To install the chaincode package on a peer B) To signal that an organization agrees to the chaincode definition parameters (e.g., endorsement policy)
Certified Practitioner Practice Exam
C) To commit the chaincode definition to the channel ledger D) To query the installed chaincode version Answer: B Explanation: “ApproveForMyOrg” records an organization’s acceptance of the proposed chaincode definition; once enough approvals are collected, the definition can be committed.
Question 16. Which method is used within chaincode to retrieve the client’s X.509 certificate subject? A) stub.GetCreator() B) cid.GetID() C) cid.GetMSPID() D) stub.GetTransient() Answer: B Explanation: The Client Identity (CID) library provides GetID() to obtain the client’s certificate subject identifier.
Question 17. What is the effect of using transient data in a transaction proposal? A) The data is permanently stored in the world state B) The data is included in the block header for audit purposes
Certified Practitioner Practice Exam
B) EventHub listener C) Identity provider D) Chaincode stub Answer: A Explanation: The Fabric Gateway service abstracts endorsement collection; the client simply submits a transaction via the gateway.
Question 20. In the Fabric Gateway model, what is the difference between evaluateTransaction() and submitTransaction()? A) evaluateTransaction() writes to the ledger, submitTransaction() only reads B) evaluateTransaction() performs a simulation (query) without ordering, while submitTransaction() sends the proposal through endorsement, ordering, and commitment phases C) evaluateTransaction() requires TLS, submitTransaction() does not D) evaluateTransaction() only works with system chaincode Answer: B Explanation: evaluateTransaction runs a read‑only query (simulation) and returns results immediately; submitTransaction follows the full transaction flow to commit changes.
Question 21. Which wallet type stores identities in plain files on the host filesystem?
Certified Practitioner Practice Exam
A) In‑memory wallet B) File‑system wallet C) CouchDB wallet D) HSM‑backed wallet Answer: B Explanation: The File‑system wallet persists identity credentials as files, whereas the in‑memory wallet keeps them only during runtime.
Question 22. What type of event does a client receive when a chaincode emits a custom event during transaction execution? A) Block event B) Chaincode event C) Config update event D) Peer lifecycle event Answer: B Explanation: Chaincode events are emitted by the chaincode and can be listened to by applications for custom triggers.
Question 23. Which configuration option enables mutual TLS (mTLS) for all Fabric node‑to‑node communications?
Certified Practitioner Practice Exam
Question 25. What does the “requiredPeerCount” parameter in a Private Data Collection definition control? A) Minimum number of peers that must endorse a transaction involving the collection B) Minimum number of peers that must store the private data for the collection to be considered valid C) Maximum number of peers that can be added to the collection D) Number of peers that will receive the collection’s transient data Answer: B Explanation: requiredPeerCount specifies how many peers must receive the private data to satisfy the collection’s dissemination policy.
Question 26. Which of the following best explains why Fabric separates endorsement from ordering? A) To allow different consensus algorithms for each phase B) To enable transaction simulation without needing a global order, improving performance and privacy C) To prevent malicious peers from creating blocks D) To reduce the size of blocks on the ordering service Answer: B Explanation: By endorsing (simulating) before ordering, Fabric can keep transaction data private during execution and avoid costly consensus for every simulation.
Certified Practitioner Practice Exam
Question 27. In a Raft ordering service, what triggers a leader election? A) Receipt of an invalid block from the current leader B) Failure to receive heartbeat messages from the leader within the election timeout C) Completion of a channel configuration update D) Addition of a new ordering node Answer: B Explanation: Raft nodes monitor leader heartbeats; if a heartbeat is missed beyond the election timeout, a new election is started.
Question 28. Which CLI command can be used to inspect the current block height of a channel? A) peer channel getinfo - c B) peer ledger height - c C) orderer block height - c D) configtxlator getinfo - c Answer: A Explanation: peer channel getinfo returns channel metadata, including the latest block number.
Certified Practitioner Practice Exam
Question 31. Which fabric component validates that a transaction’s read‑write set complies with the channel’s ACL (Access Control List) policy? A) Ordering service node B) Certificate Authority C) Peer’s validation system chaincode (VSCC) D) Chaincode shim Answer: C Explanation: The VSCC runs during validation on committing peers and checks ACLs, endorsement policies, and MVCC.
Question 32. What does the ‘Endorsement‑policy‑only’ mode allow a chaincode developer to do? A) Deploy chaincode without ever installing it on peers B) Define endorsement requirements directly in the chaincode package, bypassing channel‑level policies C) Execute chaincode in a sandboxed environment without accessing the ledger D) Automatically upgrade the chaincode version on all peers Answer: B Explanation: In “endorsement‑policy‑only” mode, the chaincode definition includes the endorsement policy, which can be used instead of a separate channel‑level policy.
Certified Practitioner Practice Exam
Question 33. Which of the following is a valid reason to use a system chaincode such as “qscc”? A) To modify the channel configuration B) To query blockchain ledger information like block height or transaction details without invoking user chaincode C) To encrypt private data collections D) To manage peer membership in a channel Answer: B Explanation: The Query System Chaincode (qscc) provides read‑only access to ledger metadata (blocks, transactions) for administrative purposes.
Question 34. In the context of Fabric’s Fabric‑CA, what is the purpose of the “affiliation” attribute when registering a user? A) To assign the user's role in the endorsement policy B) To group users under an organizational hierarchy for certificate issuance C) To define the user’s access rights to private data collections D) To specify the user’s preferred ordering service Answer: B Explanation: Affiliations represent organizational units; they help the CA issue certificates that reflect the user’s belonging to a particular org.
Certified Practitioner Practice Exam
Question 37. When a chaincode upgrade is performed, which of the following must be updated? A) The chaincode package version in the definition and the endorsement policy if changed B) Only the chaincode source code; the definition remains the same C) The ordering service’s Raft metadata D) The CA’s root certificate Answer: A Explanation: Upgrading requires packaging a new version, approving the new definition (which may include a new endorsement policy), and committing it.
Question 38. Which of the following best describes the purpose of the “peer lifecycle chaincode commit” command? A) To install the chaincode binary on a peer’s filesystem B) To record the approved chaincode definition on the channel ledger, making it active for invocation C) To query the current version of a chaincode installed on a peer D) To remove a chaincode from the peer’s runtime Answer: B Explanation: The commit operation writes the chaincode definition (including version, endorsement policy, collections) to the channel configuration, enabling execution.
Certified Practitioner Practice Exam
Question 39. In Fabric, what is the “implicit meta‑policy” used for? A) To automatically generate endorsement policies based on the number of organizations in a channel B) To define default policies for system chaincode operations when no explicit policy is set C) To enforce TLS encryption for all inter‑node traffic D) To manage the lifecycle of private data collections Answer: B Explanation: Implicit meta‑policies provide default behavior (e.g., “Admins”, “Writers”, “Readers”) for system chaincode when a specific policy is not defined.
Question 40. Which of the following is a consequence of enabling “state‑based endorsement” on a specific key? A) The key is automatically stored in a private data collection B) The endorsement policy for that key can differ from the chaincode‑level policy, requiring signatures from the specified organizations for updates C) The key becomes immutable and cannot be updated after creation D) The key is excluded from MVCC checks Answer: B
