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HFCPテストエンジンお試しセット、HFCP問題集PDF
Linux Foundation HFCP 認定試験の出題範囲：
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質問 # 13
Each peer in the Hyperledger Fabric network hosts a copy of the ledger, which also belongs to what component?
- A. The membership services
- B. The Ordering node
- C. The NoSQL databases
- D. A member channel
正解：D
解説：
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 .
質問 # 14
How should private data collection be configured and deployed?
- A. Private data collection configuration is described in a separate ison file and deployed at chaincode deployment.
- B. Private data collection is configured and deployed with the help of a dedicated REST API that is available on the orderers.
- C. Private data collection is configured at the X5C9 certification generation process of the certificate authorities.
- D. Private data collection configuration is setup at the core network structure configuration with the components.
正解：A
解説：
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.
質問 # 15
What should be taken into account at implementing efficient CouchDB queries from chaincode?
- A. Using advanced relational algebra and SQL query language options of CouchDB is enough to implement efficient queries.
- B. Using indexes, focusing on simple queries and avoiding full index scans like with operators $or, $in and
$regex. - C. Using complex indexes for certain columns is enough even if full scan operators like $or, $in and $regex are used.
- D. Using OLAP (Online analytical processing) and Cube functionality of CouchDB is enough to implement efficient queries.
正解：B
解説：
When implementing efficient CouchDB queries from chaincode in Hyperledger Fabric, it is important to use indexes effectively and focus on crafting simple queries that avoid full index scans. Operators such as $or, $in, and $regex can lead to performance issues because they often result in full scans of the database or index.
Instead, it is recommended to structure queries that make optimal use of indexes, targeting specific key-value pairs or ranges to minimize the amount of data scanned during query execution. This approach helps in maintaining high query performance and reducing the load on the CouchDB database, which is crucial for achieving efficient data retrieval in a blockchain environment.
質問 # 16
In Hyperledger Fabric, what is used if end users of the application want to keep their private key secret?
In Hyperledger Fabric, what is used if end users of the application want to keep their private key secret?
- A. Online signing
- B. Shared signing
- C. No signing is required
- D. Offline signing
正解：D
解説：
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.
質問 # 17
What types of events committed to the ledger can client applications receive using the peer's event service?
- A. Both chaincode and block events
- B. Neither chaincode nor block events
- C. Only block events
- D. Only chaincode events
正解：A
解説：
In Hyperledger Fabric, client applications can subscribe to receive both chaincode events and block events using the peer's event service. Chaincode events are generated by the chaincode itself, typically based on specific conditions coded within the chaincode operations, and are used to notify applications of specific state changes or significant occurrences. Block events inform about the addition of new blocks to the ledger, which may contain multiple transactions. This dual capability allows client applications to effectively monitor transaction confirmations and specific chaincode outputs in real time, which is critical for applications that rely on up-to-date blockchain data for processing decisions.
質問 # 18
Which of the following is the identity solution in Hyperledger Fabric?
- A. Hyperledger Fabric Orderer
- B. Membership Service Providers
- C. Hyperledger Fabric CA
- D. Hyperledger Fabric SDK
正解：B
解説：
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.
質問 # 19
Which channel feature allows organizations to run different versions of Hyperledger Fabric on their peer nodes?
- A. Channel capabilities
- B. Consensus protocols
- C. Anchor peers
- D. Endorsement policies
正解：A
解説：
Hyperledger Fabric allows different versions of the platform to coexist and interoperate on the same network through the use of channel capabilities. Channel capabilities enable organizations running different versions of Fabric binaries to participate on the same channel. These capabilities govern the features that are used by peer nodes and set the minimum version of the Fabric binaries that can be run by peers joined to the channel. This allows for heterogeneousnetwork environments where different nodes might be running different versions of Fabric software .
質問 # 20
Which organization can see data and information stored in the private data collection?
- A. Only configured members of a private data collection can see the stored data, but hash values of data are shared with other organizations of the channel.
- B. Every organization of a certain channel can see all the data and related information stored in a private data collection.
- C. Only configured members of a private data collection can see all the data and related information stored in the private data collection.
- D. Every organization of a certain Hyperledqer Fabric setup can see the all the data and related information stored in a private data collection.
正解：A
解説：
In Hyperledger Fabric, private data collections are designed to enhance privacy and confidentiality by allowing only specified members of a collection to access the stored data. These members are pre-configured when the private data collection is defined. While the actual data is restricted to these configured members, hash values of the data are distributed and stored on the ledger accessible by all organizations in the channel.
This method ensures data confidentiality while still providing a way to verify data integrity across the entire channel, as other organizations can see the hash values but not the actual data itself.
質問 # 21
Regarding peerlifecycle chaincode, which of the following is the incorrect (unsupported) subcommand for query?
- A. peer lifecycle chaincode queryinstalled
- B. peer lifecycle chaincode queryapproved
- C. peer lifecycle chaincode querycommitted
- D. peer lifecycle chaincode querypackaged
正解：D
解説：
The correct subcommands for querying in the peer lifecycle chaincode
are queryinstalled, queryapproved, checkcommitreadiness, commit, and querycommitted1. The subcommand querypackaged is not a supported subcommand for querying in the peer lifecycle chaincode.
質問 # 22
When creating a gRPC connection to the Gateway peer using Transport Layer Security (TLS), what information must be supplied by the client application?
- A. A common connection profile that includes the Gateway peer address and TLS certificate.
- B. The endpoint address of the Gateway peer and the certificate of the TLS certificate authority.
- C. The client private key and the public key of the TLS certificate authority.
- D. The Gateway peer host name, service port number, and a TLS host name override.
正解：B
解説：
When creating a gRPC connection to the Gateway peer in Hyperledger Fabric using Transport Layer Security (TLS), the client application must supply the endpoint address of the Gateway peer and the certificate of the TLS certificate authority. This configuration is essential to establish a secure communication channel. The endpoint address specifies where the Gateway peer is located, which the client uses to connect. The certificate of the TLS certificate authority is crucial for validating the identity of the Gateway peer, ensuring that the connection is secure and that the data being transmitted is encrypted. This setup helps prevent man-in-the-middle attacks and ensures that sensitive data remains confidential during transmission.
質問 # 23
In Raft, there are two places for configuration. One is local configuration. What is the other?
- A. Consensus configuration
- B. Global configuration
- C. Peer configuration
- D. Channel configuration
正解：D
解説：
In Raft, configuration occurs at two levels: local and channel. The local configuration pertains to node-specific settings such as TLS communication and file storage. The channel configuration, on the other hand, defines the membership and operational parameters of the Raft cluster for a specific channel, including settings like heartbeat frequency and leader timeouts. This dual-level configuration allows for precise control over the behavior of Raft nodes within the Hyperledger Fabric network .
質問 # 24
In Hyperledger Fabric a transaction is initiated where?
- A. Client
- B. Orderer
- C. Endorser
- D. IPeer
正解：A
解説：
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.
質問 # 25
When using "off-line signing" in the Fabric Gateway client API, what information from each message is used to generate the cryptographic signature?
- A. The transaction validation code
- B. The message digest
- C. The client X.509 certificate
- D. The transaction ID
正解：B
解説：
When using "off-line signing" in the Fabric Gateway client API, the cryptographic signature is generated using the message digest. This digest is a hashed representation of the transaction's content, ensuring the integrity and non-repudiation of the transaction as it moves through the Fabric network. This method allows for secure transaction signing without exposing private keys directly on the client-side, aligning with security best practices .
質問 # 26
What is the only way to recover from a failed migration from Kafka to Raft?
- A. Rebuild the network from scratch.
- B. Revert to the previous version of Kafka.
- C. Restore the state from a backup.
- D. Retry the migration from Kafka to Raft.
正解：C
解説：
Recovering from a failed migration from Kafka to Raft in Hyperledger Fabric involves restoring the state from a backup. This is necessary because once the ordering service is migrated to Raft and begins committing transactions, reverting to Kafka is not supported without a previous backup. If a migration is botched, and a backup was made at the appropriate point, administrators can roll back to this backup to restore the system to its pre-migration state .
質問 # 27
An endorsement policy lists what?
- A. The number of organizations involved in a transaction.
- B. The identities required for endorsing a transaction.
- C. The order in which transactions are executed.
- D. The number of peers needed to endorse a transaction.
正解：B
解説：
In Hyperledger Fabric, an endorsement policy specifies which network participants, identified by their digital identities, must endorse a transaction before it can be considered valid. This is crucial for the network's security and integrity, as it controls how transactions are approved andadded to the ledger. Endorsement policies are part of the channel configuration and can be customized to fit the specific needs of a business network. They dictate the necessary endorsements from specific organizations or even particular roles within those organizations, ensuring that only authorized entities can validate transactions. This mechanism supports the collaborative yet secure nature of the enterprise blockchain, where trust is decentralized across different organizations that are part of the network.
質問 # 28
When submitting a transaction, how can a client application send information to be stored only in a private data collection?
- A. Send it as a chaincode event.
- B. Encrypt it using the client private key.
- C. Include it as transient data.
- D. Transfer it using an off-chain data store.
正解：C
解説：
In Hyperledger Fabric, to send information that should be stored only in a private data collection during a transaction submission, the information must be included as transient data. Transient data is sent along with the transaction proposal but is not recorded on the ledger; instead, it is used within the chaincode for processing and can then be stored in private collections as needed. This method ensures that sensitive information is kept out of the public ledger and is only available to authorized parties as defined in the private data collection configuration. Transient data provides a secure way to handle sensitive or confidential information within the network without exposing it on the shared ledger.
質問 # 29
For an endorsed transaction, the gateway service forwards the transaction to the ordering service, which orders it with other endorsed transactions and then completes what?
- A. Sends the transaction to the endorsement phase.
- B. Broadcasts the transaction to all peers in the channel.
- C. Packages all endorsed transactions into a block.
- D. Sends the transaction to the validation phase.
正解：C
解説：
For an endorsed transaction, the gateway service forwards the transaction to the ordering service. The ordering service then packages this transaction with other endorsed transactions into a block. This block is subsequently distributed across the network to all peers for validation and commitment to the ledger. The ordering process ensures the maintenance of transaction order across the network, crucial for the consistency and integrity of the blockchain .
質問 # 30
What is a range query with a start and end key?
- A. A query that searches for ledger entries that have values matching the range.
- B. A query that searches for a specific value in a composite key and all values after it.
- C. A query that searches for all keys that are in the range defined by the start and end keys.
- D. A query that searches for all the key field in the value.
正解：C
解説：
In Hyperledger Fabric, a range query with a start and end key is a type of query that searches for all ledger entries whose keys fall within the specified range defined by the startKey and endKey. This is used, for example, to retrieve a subset of assets from the ledger based on their key values, effectively iterating over a specified range .
質問 # 31
Which concept of the RAFT ordering service relates to the ingestion of new log entries; their replication to other ordering nodes; and managing when an entry is considered committed?
- A. Consenter set
- B. Leader
- C. Endorsement
- D. Quorum
正解：B
解説：
In the RAFT ordering service within Hyperledger Fabric, the concept of the "Leader" is crucial for the ingestion of new log entries, their replication to other ordering nodes, and managing when an entry is considered committed. In a RAFT-based ordering service, the leader node is responsible for managing the log entries; it receives all client requests, appends them to its log, and replicates these logs to the follower nodes.
The leader also plays a crucial role in ensuring that there is a consensus on the order of transactions before they are committed to the ledger. The leader is dynamically elected by the cluster nodes and can change due to network conditions or node failures. This role is pivotal in the RAFT consensus mechanism for maintaining a consistent and reliable ordering service.
質問 # 32
Which of the following information do signature policies provide when creating a network in Hyperledger Fabric?
- A. Type of consensus algorithm used
- B. Identity specific users who must sign in order to satisfy a policy.
B Number of nodes in the network - C. Private keys of all network participants.
正解：B
解説：
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.
質問 # 33
What is necessary for a chaincode to become ready to commit on a channel?
- A. The policy Channel/Application/Writers must be satisfied.
- B. The policy /Channel/Application/LifecycleEndorsement must be satisfied.
- C. The chaincode must have the endorsement policies correctly defined.
- D. The chaincode must be previously installed on the channel's peers.
正解：B
解説：
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.
質問 # 34
What happens if the user submits a transaction with no matching function?
- A. The unknownTransaction function is called.
- B. The peer will have rejected the transaction.
- C. Nothing, the transaction is ignored.
- D. The first transaction function is called.
正解：A
解説：
In Hyperledger Fabric, if a user submits a transaction with no matching function specified in the smart contract, theunknownTransactionfunction is invoked by default. This function serves as a catch-all method that can be used to handle cases where the transaction type is not recognized, providing a mechanism to manage or log these occurrences effectively .
質問 # 35
What is the difference between chaincode, transaction, and block events?
- A. Chaincode events must be programmed in the smart contract, transaction and block events work out of the box
- B. They are pretty much the same both regarding functionality and programming effort as well.
- C. Use setEvent, setTransactionEvent, setBlockEvent to emit chaincode, transaction and block events in the chaincode.
- D. Block events must be programmed in the smart contract, chaincode events work out of the box.
正解：A
解説：
In Hyperledger Fabric, chaincode events, transaction events, and block events serve different purposes and are emitted differently. Chaincode events must be explicitly programmed into the smart contract. Developers need to use thesetEventmethod within the chaincode to emit custom events that applications can listen to. On the other hand, transaction and block events are generated by the system automatically. These events notify listening applications of new blocks added to the chain or transactions included in blocks, without requiring any additional programming effort within the smart contracts.
質問 # 36
In Hyperledger Fabric, Intercommunication is how a smart contract in a channel updates the World State database. It is achieved by what process?
- A. Making use of the cross channel Consensus mechanism.
- B. Configuring the Peer-to-peer endorsement options.
- C. Setting the endorsement policy to communicate with all peers.
- D. Calling smart contracts within the channel and in different channels.
正解：D
解説：
Intercommunication in Hyperledger Fabric regarding how smart contracts update the World State database is primarily achieved by calling other smart contracts, both within the same channel and across different channels. This process allows smart contracts, also known as chaincode, to interact and transact across the network, updating the World State as necessary based on business logic defined in the contracts. This capability is crucial for complex business processes that span multiple contracts and possibly multiple channels. Unlike setting endorsement policies or configuring peer-to-peer options, calling other smart contracts directly facilitates dynamic and direct interaction between business processes, enhancing the modularity and efficiency of the network. Cross-channel communication must be carefully managed within the permissions and policies defined in the network to maintain security and integrity.
質問 # 37
Which actions are combined into a single function by the Fabric Gateway client APIs to support transaction submission with a single line of code?
- A. Endorsement and Commitment
- B. Ordering and Commitment
- C. Endorsement, Submit, and Commitment
- D. Validation and Commitment
正解：C
解説：
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 .
質問 # 38
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