Free Practice Questions for Linux Foundation HFCP Exam

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​​.

For developers looking to iteratively test and develop smart contracts in Hyperledger Fabric without the overhead of the full lifecycle process for each update, the recommended approach is to run the chaincode in development mode. This mode allows developers to test and debug chaincode directly on their machines without having to package, install, approve, and commit changes on the network each time. Development mode simplifies the iterative development process by allowing direct interaction with the chaincode during its development, making it easier to make and test changes quickly and efficiently. This contrasts with other methods that involve manual updates, redeployments, or using a production network, all of which are more time-consuming and complex​​.

In Hyperledger Fabric, the ordering nodes that are actively participating in the consensus mechanism for a given channel are referred to as the "Consenter set." These nodes are part of the ordering service and are responsible for creating blocks by ordering transactions and ensuring consistency across the network. The Consenter set receives the transaction logs that need to be replicated across other orderers and peers in the network. This is distinct from the "Committer set," which comprises nodes that commit blocks to their ledger, and "Endorsers," which are responsible for endorsing transactions by checking them against the chaincode execution policies​​.

In Hyperledger Fabric, when a transaction that includes thedelState("A")function is committed, it results in the removal of the state of the key "A" from the current state database. However, the history of all transactions that have affected the key "A" remains intact in the ledger. This operation ensures that while the current state reflects the deletion, the immutability and traceability of the ledger are preserved, allowing for auditability and verification of past states. Options such as setting an empty value to the key or altering the transaction history are not supported, as they would violate the principles of immutability and transparency central to blockchain technology. Therefore, the correct outcome of adelState("A")operation is that the current state of "A" is deleted, but its transaction history remains accessible in the ledger​​.

For a chaincode to become ready to commit on a channel in Hyperledger Fabric, it is necessary that the policy "/Channel/Application/LifecycleEndorsement" be satisfied. This policy specifies who needs to approve the chaincode definition before it can be committed to the channel. It ensures that the chaincode deployment is endorsed according to the governance standardsagreed upon by the network participants, typically requiring a majority or other specified fraction of the organizations in the network to endorse the change. This lifecycle endorsement policy is key to maintaining a secure and agreed-upon update process for chaincodes on the channel​​.

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​​.

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​​.

In Hyperledger Fabric, if end users of the application want to keep their private key secret and secure, they would use offline signing. Offline signing involves signing transactions on a device or in an environment that is not connected to the network or the internet. This method ensures that the private key used for signing does not get exposed to the network and reduces the risk of compromise. Offline signing is especially important in scenarios where security and privacy are paramount, as it allows users to maintain control over their private keys at all times​​.

In Hyperledger Fabric's modular architecture, the Membership Service Provider (MSP) is the pluggable component responsible for handling identities. The MSP abstracts the identity validation and authentication processes, allowing organizations to implement their preferred identity services while maintaining interoperability within the network. It defines the rules by which identities are validated, issued, and revoked. This component is essential for the permissioned nature of Hyperledger Fabric, ensuring that only authorized participants can execute specific actions on the network​​.