Q: Which directory is created by the idemixgen tool along with the ca directory and msp directory when configuring membership?

B Explanation: Theidemixgentool is used to create configuration files for the Identity Mixer based MSP (Membership Service Provider) in Hyperledger Fabric.When configuring membership, theidemixgentool creates three directories:/ca/,/msp/, and/user/1. The/ca/directory contains the issuer secret key, issuer public key, and revocation key, which should only be present for a Certificate Authority (CA). The/msp/directory contains the issuer public key and revocation public key, which are required to set up an MSP that verifies Identity Mixer signatures.The/user/directory specifies a default signer configuration1. Therefore, the correct answer is the user directory, which is created alongside the ca and msp directories by theidemixgentool.

Question 1

Which subcommand adds a peer to a channel in Hyperledger Fabric?

Accepted Answer

D

Explanation: In Hyperledger Fabric, the correct subcommand to add a peer to a channel is peer channel join. This command is used by a peer node to join an existing channel. The command requires a block to be specified which typically is the genesis block of the channel, allowing the peer to synchronize with the channel's ledger from the beginning. Other commands like peer channel fetch, peer channel create, and peer channel update serve different purposes. peer channel fetch retrieves blocks from a channel, peer channel create is used to set up a new channel, and peer channel update modifies channel settings. Thus, peer channel join is the specific command used to connect a peer to a channel​​.

Question 2

An enterprise blockchain is a permission blockchain node distributed to whom?

Accepted Answer

C

Explanation: In Hyperledger Fabric, the enterprise blockchain is a permissioned network where nodes are distributed among the member organizations that participate in the blockchain network. This is in contrast to a public blockchain where anyone can participate anonymously. In a permissioned blockchain like Hyperledger Fabric, the participants are known entities within a business network, such as enterprises or organizations, that have specific permissions and roles within the network. This setup enhances security and trust as each participant is vetted and authorized to take part in the network operations. The architecture of Hyperledger Fabric is designed to support such a governance model, where multiple organizations can interact in a secure and regulated environment, maintaining their own ledgers but sharing data that require consensus across known entities​​.

Question 3

Which of the following is the identity solution in Hyperledger Fabric?

Accepted Answer

D

Explanation: In Hyperledger Fabric, the identity solution that manages user identities and authenticates participants on the network is facilitated by Membership Service Providers (MSPs). MSPs are crucial for defining the rules by which identities are validated, authenticated, and allowed access to the network. MSPs handle the issuance of certificates and define the roles and permissions associated with participant identities, enabling permissioned interactions on the blockchain. This differs from Hyperledger Fabric CA, which primarily issues and revokes certificates as part of identity management but is used in conjunction with MSPs to provide comprehensive identity solutions within the network​​.

Question 4

In Hyperledger Fabric, CouchDB is enabled as the state database by changing the state Database configuration option from goleveldb to what?

Accepted Answer

D

Explanation: In Hyperledger Fabric, to enable CouchDB as the state database, the stateDatabase configuration option in the core.yaml file must be changed from goleveldb to CouchDB. This change directs the peer to use CouchDB instead of the default LevelDB for storing the world state, which can then be queried using rich queries and provides additional features like indexing​​.

Question 5

Each peer in the Hyperledger Fabric network hosts a copy of the ledger, which also belongs to what component?

Accepted Answer

D

Explanation: In Hyperledger Fabric, each peer in the network hosts a copy of the ledger, which is associated with a member channel. The ledger itself is comprised of a blockchain to store the immutable, sequenced record in blocks, and a state database to maintain the current state of the ledger. There is one ledger per channel, and each peer maintains a copy of the ledger for each channel of which they are a member .

Question 6

Which directory is created by the idemixgen tool along with the ca directory and msp directory when configuring membership?

Accepted Answer

B

Explanation: The​idemixgen​tool is used to create configuration files for the Identity Mixer based MSP (Membership Service Provider) in Hyperledger Fabric.​When configuring membership, the​idemixgen​tool creates three directories:​/ca/,​/msp/, and​/user/1. The​/ca/​directory contains the issuer secret key, issuer public key, and revocation key, which should only be present for a Certificate Authority (CA). The​/msp/​directory contains the issuer public key and revocation public key, which are required to set up an MSP that verifies Identity Mixer signatures.​The​/user/​directory specifies a default signer configuration1. Therefore, the correct answer is the user directory, which is created alongside the ca and msp directories by the​idemixgen​tool.

Question 7

What is the purpose of the ordering service in Hyperledger Fabric model?

Accepted Answer

C

Explanation: The primary purpose of the ordering service in Hyperledger Fabric is to assemble transactions into blocks and ensure their correct sequencing on the blockchain ledger. This service takes validated transactions, orders them chronologically, and packages them into blocks. These blocks are then distributed to all peers on the network for final validation and commitment to their respective ledgers. This process is crucial for maintaining the integrity and consistency of the ledger across the distributed network. The ordering service does not manage identities or endorse transactions, nor does it validate transactions or directly maintain the blockchain ledger beyond the sequencing and packaging of transactions​​.

Question 8

Which actions are combined into a single function by the Fabric Gateway client APIs to support transaction submission with a single line of code?

Accepted Answer

B

Explanation: The Fabric Gateway client APIs in Hyperledger Fabric streamline the transaction submission process by combining endorsement, submission, and commitment into a single function. This allows client applications to efficiently manage transaction submissions with a single line of code, specifically through the SubmitTransaction() function. This consolidation simplifies the interaction model for applications, enabling a focus on business logic rather than the underlying blockchain infrastructure details .

Question 9

In Hyperledger Fabric a transaction is initiated where?

Accepted Answer

C

Explanation: In Hyperledger Fabric, a transaction is initiated by a client application. The client creates a transaction proposal and sends it to endorsing peers. The role of the client is critical as it acts as the initiator of transactions, constructing and proposing transactions to the network for endorsement and then submitting the endorsed transactions to the ordering service for inclusion in the blockchain. The client essentially orchestrates the process of transaction creation, endorsement, and submission, starting the entire transaction flow​​.

Question 10

Which of the following statements describes Chaincode correctly?

Accepted Answer

B

Explanation: Chaincode in Hyperledger Fabric is essentially smart contract software that defines assets and the transaction instructions for modifying these assets on the ledger. Chaincode functions as the business logic layer of the network, where the rules for interacting with the ledger are specified. It is executed on the network peers and is used to encode the policies and constraints associated with asset exchanges or updates within the business network. This setup allows organizations to automate processes and enforce consistency and compliance across transactions​​.

Question 11

What is true about the historic states in Hyperledger Fabric model?

Accepted Answer

C

Explanation: Historic states in the Hyperledger Fabric ledger are immutable, meaning they cannot be altered after they have been committed to the ledger. This immutability ensures the integrity and traceability of all transactions on the network. Once a transaction is recorded, it is permanent, and its history can be audited to trace back all operations affecting any piece of data. This feature is fundamental in blockchain technology, providing a verifiable and tamper-evident record. The immutability of historic states is a key component of the trust and security model in Hyperledger Fabric, contrary to options that suggest these records can be modified or are inaccessible​​.

Question 12

Which of the following is the correct role of orderer nodes?

Accepted Answer

A

Explanation: The primary role of orderer nodes in Hyperledger Fabric is to order and package endorsed transactions into blocks. Orderers receive transactions from various peers, ensure that these transactions are in a consistent order, and then package them into blocks that are subsequently appended to the blockchain. This function is crucial for maintaining the consistency and integrity of the ledger across all participating nodes. Orderer nodes do not issue tokens, enforce peer endorsements, or reorder stored blocks for data compression. Instead, their main function is integral to the consensus and ledger maintenance processes within a Hyperledger Fabric network​

Question 13

Which of the following sources provide block events?

Accepted Answer

B

Explanation: In Hyperledger Fabric, block events are provided by peers. Whenever a block is committed to a peer's ledger, that peer generates a corresponding event. These events can include the full block content or a summary of the transactions within the block, allowing applications to register and receive notifications about these events. This setup is crucial for applications that need to respond to changes recorded on the blockchain in real-time .

Question 14

Which of the following information do signature policies provide when creating a network in Hyperledger Fabric?

Accepted Answer

A

Explanation: In Hyperledger Fabric, signature policies specify the identities of specific users who must sign a transaction for it to be considered valid. These policies define the endorsement rules associated with a chaincode and are a critical component of the transaction flow. They ensure that transactions are endorsed by the correct entities as stipulated by the governance of the network. Signature policies are not related to the number of nodes, private keys of participants, or the type of consensus algorithm used but are strictly about defining which users or member organizations' signatures are required to fulfill transaction criteria.

Question 15

How should private data collection be configured and deployed?

Accepted Answer

D

Explanation: In Hyperledger Fabric, private data collections are configured using a separate JSON file that describes the details of the collection, such as the name, policy, and member organizations that have access to it. This configuration file is included during the chaincode deployment process. The collections configuration file defines how private data is managed, including its lifecycle, storage, and dissemination between authorized peers. By configuring private data collections in this manner, organizations ensure that sensitive information is only accessible to specific participants in the network, thus maintaining confidentiality and compliance with data governance standards​​.

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