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Certified Hyperledger Fabric Developer (CHFD) Practice Exam
1. What is blockchain technology? A) A centralized database system B) A distributed ledger that records transactions in a secure, immutable way C) A type of cloud computing service D) A traditional relational database Answer: B Explanation: Blockchain is a distributed ledger that securely records transactions without a central authority. 2. Which of the following is a primary difference between blockchain and traditional databases? A) Blockchain uses a centralized model while databases are decentralized B) Blockchain data is immutable, whereas traditional databases allow modification C) Traditional databases use cryptography for security, unlike blockchains D) Blockchains support SQL queries by default Answer: B Explanation: Blockchains are designed to be immutable, meaning once data is recorded it cannot be altered, unlike traditional databases. 3. What does the term “ledger” refer to in blockchain technology? A) A digital wallet for cryptocurrencies B) A record of all transactions in a blockchain network C) A smart contract script D) A network consensus algorithm Answer: B Explanation: In blockchain, the ledger is the digital record that stores every transaction in the network. 4. Which blockchain type is characterized by permissioned access and often used by enterprises? A) Public blockchain B) Private blockchain C) Consortium blockchain D) Both B and C Answer: D Explanation: Both private and consortium blockchains restrict access and are typically used by organizations. 5. What is the role of consensus algorithms in blockchain? A) They control network firewalls B) They help ensure all nodes agree on the ledger’s state C) They encrypt user data only D) They generate blockchain addresses Answer: B
Explanation: Consensus algorithms ensure that all participants agree on a single version of the truth in the ledger.
6. Which of the following best defines smart contracts? A) Contracts signed with a digital pen B) Self-executing code that runs on the blockchain C) Legal documents stored on a server D) A blockchain node’s configuration file Answer: B Explanation: Smart contracts are self-executing pieces of code stored on the blockchain that automatically enforce rules and agreements. 7. What distinguishes Hyperledger Fabric from other blockchain platforms? A) It only supports Bitcoin transactions B) It is designed with a modular architecture for flexibility C) It exclusively uses proof-of-work D) It does not support smart contracts Answer: B Explanation: Hyperledger Fabric is known for its modular architecture that allows for plug-and- play components. 8. In Hyperledger Fabric, what is a “peer”? A) A node that orders transactions B) A client application C) A node that maintains the ledger and endorses transactions D) A smart contract deployment tool Answer: C Explanation: Peers in Hyperledger Fabric maintain the ledger and validate transactions. 9. Which component in Hyperledger Fabric is responsible for ordering transactions into blocks? A) Peer node B) Orderer C) Client D) Chaincode Answer: B Explanation: The Orderer collects endorsed transactions and orders them into blocks for the network. 10. What is the purpose of channels in Hyperledger Fabric? A) To isolate transaction data among a subset of network participants B) To broadcast transactions to all nodes C) To encrypt blockchain data D) To serve as smart contract repositories Answer: A
Answer: B Explanation: Endorsement policies specify which and how many peers must verify a transaction before it is accepted.
16. What is the purpose of using Docker in setting up a Hyperledger Fabric network? A) To compile chaincode automatically B) To containerize and manage different Fabric components easily C) To provide an alternative consensus mechanism D) To develop client applications Answer: B Explanation: Docker is used to containerize the components, making deployment and management of the network simpler. 17. Which of the following best describes the transaction flow in Hyperledger Fabric? A) Transaction submission, block creation, mining reward distribution B) Transaction proposal, endorsement, ordering, validation, and commitment C) Transaction signing, broadcasting, and immediate commitment D) Transaction encryption, decryption, and storage Answer: B Explanation: Hyperledger Fabric follows a sequence of proposal, endorsement, ordering, validation, and commitment for transactions. 18. What is the main difference between transaction endorsement and transaction validation in Fabric? A) Endorsement occurs by peers before ordering; validation happens during block commit B) Endorsement encrypts data while validation decrypts it C) Endorsement uses a public key; validation uses a private key D) There is no difference Answer: A Explanation: Endorsement is performed by peers prior to ordering, and validation occurs during the block commit phase. 19. Which state database options are available in Hyperledger Fabric? A) MySQL and PostgreSQL B) CouchDB and LevelDB C) MongoDB and Redis D) OracleDB and SQLServer Answer: B Explanation: Hyperledger Fabric supports CouchDB and LevelDB for maintaining the world state. 20. What does “immutability” in a blockchain refer to? A) The inability to change or delete data once it is recorded B) The ability to edit transactions at will C) The flexibility of adding new data D) The encrypted nature of data
Answer: A Explanation: Immutability means that once data is recorded on the blockchain, it cannot be modified or erased.
21. Which component is critical for the separation of transaction execution and ordering in Fabric? A) The ledger B) The orderer C) The peer D) The channel Answer: B Explanation: The orderer is responsible for separating transaction execution from ordering, ensuring scalability and modularity. 22. What is a key advantage of Hyperledger Fabric’s modular architecture? A) It limits customization options B) It allows components to be swapped or upgraded independently C) It requires a single consensus algorithm D) It only supports one programming language Answer: B Explanation: Modular architecture enables independent customization and upgrading of components. 23. Which file is typically used to configure a local Hyperledger Fabric network? A) config.json B) fabric-config.yaml C) chaincode.ini D) network.properties Answer: B Explanation: The fabric-config.yaml (or similar configuration files) is used to define network settings. 24. How is chaincode deployed on a Fabric network? A) By directly inserting code into the ledger B) By packaging, installing, instantiating, and then invoking it C) By manually editing the blockchain’s source code D) Through automated scripts without packaging Answer: B Explanation: Chaincode deployment involves packaging the code, installing it on peers, instantiating it on a channel, and finally invoking it. 25. Which consensus mechanism is NOT used in Hyperledger Fabric? A) Raft B) Kafka C) Proof-of-Work D) PBFT
Answer: B Explanation: TLS (Transport Layer Security) is used to secure communication among nodes in a Fabric network.
31. What is the primary purpose of Fabric-CA? A) To manage node configuration files B) To handle identity management and certificate issuance C) To deploy chaincode D) To monitor network performance Answer: B Explanation: Fabric-CA provides a certificate authority service to manage identities and authentication within the network. 32. Which tool is commonly used to monitor Hyperledger Fabric networks? A) Wireshark B) Grafana along with Prometheus C) Apache Kafka Monitor D) Jenkins Answer: B Explanation: Grafana and Prometheus are widely used to monitor metrics and health of Fabric networks. 33. What does the term “world state” refer to in Hyperledger Fabric? A) The global blockchain network configuration B) The current state of the ledger representing the latest data values C) The entire history of transactions D) A type of consensus algorithm Answer: B Explanation: The world state is a database that holds the latest values of ledger states for quick lookup. 34. How does Hyperledger Fabric support role-based access control (RBAC)? A) By allowing every user the same privileges B) Through Fabric-CA and Access Control Lists (ACLs) that assign specific permissions C) By using only public keys D) By disabling identity management Answer: B Explanation: RBAC in Fabric is enforced using identity management tools like Fabric-CA along with ACLs to define roles and permissions. 35. What is one of the benefits of using a consortium blockchain? A) Complete anonymity for all transactions B) Shared control among a group of organizations with known identities C) Unlimited scalability without restrictions D) It eliminates the need for consensus mechanisms Answer: B
Explanation: Consortium blockchains offer shared control while maintaining trust among participating organizations.
36. Which of the following is NOT a core component of Hyperledger Fabric? A) Peer nodes B) Orderer nodes C) Miner nodes D) Client applications Answer: C Explanation: Fabric does not use miner nodes; it relies on orderers and peers instead. 37. What is one key characteristic of private blockchains? A) They are open to the public for participation B) They require permission for network access and participation C) They always use proof-of-work D) They have no governance model Answer: B Explanation: Private blockchains restrict participation and require permission to join the network. 38. What is the primary function of chaincode in Hyperledger Fabric? A) To provide a user interface B) To enforce business logic and automate processes C) To mine new blocks D) To manage network peers Answer: B Explanation: Chaincode contains business logic that is executed when transactions are invoked on the network. 39. Which phase in the chaincode lifecycle involves executing the smart contract logic? A) Packaging B) Instantiation C) Invocation D) Installation Answer: C Explanation: The invocation phase triggers the chaincode’s execution and business logic. 40. What is the significance of the “endorsement phase” in a transaction’s lifecycle? A) It ensures the transaction is encrypted B) It verifies that the transaction meets the endorsement policy before ordering C) It immediately commits the transaction to the ledger D) It deploys chaincode automatically Answer: B Explanation: The endorsement phase involves peers signing off on a transaction to meet policy requirements before it is processed further.
46. Which programming language is most commonly associated with writing Fabric chaincode? A) Ruby B) Go C) PHP D) C++ Answer: B Explanation: Go is one of the primary languages used for developing chaincode in Hyperledger Fabric. 47. What is one reason for using Docker-Compose in a Fabric network setup? A) To manage containerized deployment of multiple Fabric components B) To compile chaincode C) To write smart contracts D) To control network encryption keys Answer: A Explanation: Docker-Compose simplifies the deployment and management of multiple containerized Fabric components. 48. How does Hyperledger Fabric support multi-organization networks? A) By using a single organization for all transactions B) Through channels and endorsement policies that allow multiple organizations to interact C) By allowing only one identity per network D) By using proof-of-work consensus Answer: B Explanation: Fabric supports multi-organization networks through channels and policies that define participation and data sharing. 49. What is the role of a Fabric client application? A) To store the ledger data permanently B) To interact with the network by invoking chaincode and querying the ledger C) To validate transactions D) To generate encryption keys Answer: B Explanation: Client applications use Fabric SDKs to submit transactions and query the ledger, interacting with the network. 50. Which SDK languages are officially supported by Hyperledger Fabric? A) Python, Ruby, and PHP B) Go, Java, and Node.js C) C#, Swift, and Kotlin D) C++, Perl, and Lua Answer: B Explanation: Hyperledger Fabric provides SDKs for Go, Java, and Node.js for developing client applications.
51. What is the significance of a “transaction proposal” in Fabric? A) It is the final commitment of the transaction B) It is the initial request sent to peers for endorsement before ordering C) It is used solely for auditing purposes D) It decrypts the ledger data Answer: B Explanation: The transaction proposal is sent by the client to peers to gather endorsements prior to ordering and committing the transaction. 52. In the context of Fabric, what is meant by “chaincode instantiation”? A) Packaging chaincode into a container B) Deploying chaincode on a channel and making it active for use C) Testing chaincode locally only D) Archiving outdated chaincode Answer: B Explanation: Instantiation refers to deploying chaincode on a channel, making it ready for transaction processing. 53. Which process in Hyperledger Fabric involves committing a block of transactions to the ledger? A) Chaincode invocation B) Block commit C) Transaction proposal D) Chaincode packaging Answer: B Explanation: Block commit is the phase where validated blocks of transactions are written to the ledger. 54. What is the function of the CouchDB state database in Fabric? A) To perform transaction ordering B) To provide a JSON-based view of the world state C) To serve as the ledger itself D) To compile chaincode Answer: B Explanation: CouchDB is used as a state database that stores world state data in JSON format, allowing for complex queries. 55. Which Fabric component is used to handle events such as block commits and chaincode events? A) Orderer B) Event Hub (or Event Service) C) Fabric-CA D) Peer only Answer: B Explanation: The Event Hub (or Event Service) notifies client applications about blockchain events such as block commits and chaincode events.
61. Which statement best describes Hyperledger Fabric’s approach to GDPR and data privacy? A) Fabric ignores data privacy concerns B) Fabric incorporates features like private channels and access controls to comply with privacy regulations C) Fabric publicly exposes all transaction details D) Fabric stores personal data unencrypted Answer: B Explanation: Fabric’s design includes privacy features such as channels and strict access control that can help meet GDPR requirements. 62. How does Fabric ensure the security of smart contracts (chaincode)? A) By keeping the source code secret B) Through peer-based endorsement and chaincode validation processes C) By running on unencrypted channels D) By using a single static key Answer: B Explanation: Security is enforced by having multiple peers endorse and validate transactions before committing them. 63. What does “fabric network scaling” primarily refer to? A) Increasing the block size limit only B) Adding more peers and resources to handle increased transaction loads C) Decreasing the number of organizations D) Changing the programming language of chaincode Answer: B Explanation: Scaling involves expanding the network by adding peers and computing resources to support higher transaction volumes. 64. Which of the following best describes high availability in Hyperledger Fabric? A) A network that is rarely updated B) A network design that minimizes downtime through redundancy and fault tolerance C) A network that allows only one organization D) A network that uses manual processes exclusively Answer: B Explanation: High availability is achieved by building redundancy and fault tolerance into the network architecture. 65. What is the importance of load balancing in a Fabric network? A) It decreases the number of transactions allowed B) It distributes network traffic evenly across nodes to avoid bottlenecks C) It combines multiple ledgers into one D) It disables endorsement policies Answer: B Explanation: Load balancing ensures that no single node is overwhelmed, thereby optimizing performance.
66. Which Fabric component would you monitor to diagnose network latency issues? A) Peer node logs and orderer performance metrics B) Only the chaincode source code C) Client application design D) Fabric-CA enrollment logs Answer: A Explanation: Peer node and orderer logs provide insights into latency and performance bottlenecks. 67. In Fabric’s multi-organization setup, what is a common challenge that must be managed? A) Ensuring each organization uses the same hardware brand B) Aligning different policies, trust models, and data-sharing requirements C) Preventing organizations from using smart contracts D) Using a single programming language for all organizations Answer: B Explanation: Multi-organization networks require careful coordination of policies and trust relationships. 68. Which Hyperledger Fabric feature helps in auditing network activity? A) The use of ephemeral data only B) Detailed logging and immutable ledger records C) Temporary chaincode execution D) Rotating encryption keys every minute Answer: B Explanation: Immutable ledger records and comprehensive logging enable thorough auditing of network activity. 69. How can Fabric network administrators perform backup and recovery? A) By copying the ledger files and state databases regularly B) By relying solely on cloud services C) By restarting the network daily D) By removing endorsement policies Answer: A Explanation: Regular backups of ledger data and state databases are crucial for disaster recovery. 70. What is a key consideration when upgrading Fabric network components? A) Ensuring backward compatibility and minimal downtime B) Changing the network’s underlying consensus mechanism daily C) Removing all channel configurations D) Disabling client SDKs Answer: A Explanation: Upgrades must be performed with minimal impact on network availability and compatibility.
76. What does “access control” in Hyperledger Fabric determine? A) Which chaincode language is used B) Who can perform specific actions on the network C) The speed of transaction processing D) The format of the ledger Answer: B Explanation: Access control rules specify which identities have permissions to perform certain operations within the network. 77. Which factor is crucial for ensuring data confidentiality on a Fabric channel? A) The use of public addresses B) Strict channel membership and proper encryption C) Open access to all transaction logs D) Disabling smart contracts Answer: B Explanation: Confidentiality is maintained by restricting channel membership and encrypting data in transit. 78. How does Fabric handle data encryption “at rest”? A) It doesn’t support encryption at rest B) Through integration with external encryption tools and proper state database configuration C) By keeping the ledger in plain text D) By using blockchain forks Answer: B Explanation: Data encryption at rest is achieved by configuring the state database and integrating with external encryption solutions. 79. Which approach is recommended for testing Fabric chaincode? A) Deploying directly on production without tests B) Using unit testing frameworks and a simulated network environment C) Relying only on manual testing D) Using a public blockchain testnet Answer: B Explanation: Unit tests and simulated networks help catch issues early before deploying to production. 80. What is one common strategy for debugging chaincode issues in Fabric? A) Ignoring error logs B) Using mock peers and detailed logging to simulate and trace transaction flows C) Immediately rewriting the entire chaincode D) Disabling the endorsement process Answer: B Explanation: Detailed logging and simulated environments allow developers to trace issues and debug chaincode efficiently.
81. Which best practice is recommended for maintaining chaincode quality? A) Avoiding any form of testing B) Regular code reviews, version control, and automated testing C) Not using versioning D) Relying solely on manual deployment Answer: B Explanation: Regular code reviews, proper versioning, and automated testing ensure that chaincode remains reliable and secure. 82. What is one reason for using a modular approach in Fabric network design? A) To complicate configuration management B) To allow independent upgrades and troubleshooting of components C) To force all organizations to use identical hardware D) To remove security features Answer: B Explanation: A modular design enables administrators to upgrade and troubleshoot components individually without impacting the entire network. 83. How does Fabric address node failures? A) By requiring manual intervention for each failure B) Through redundancy, fault tolerance, and automated recovery procedures C) By disabling the network D) By removing the affected organization Answer: B Explanation: Fabric is designed with fault tolerance in mind, using redundancy and automated recovery to handle node failures. 84. Which topic is NOT directly covered by Hyperledger Fabric governance? A) Network policies and code review standards B) Auditing and compliance C) Smart contract legal disputes in external courts D) Network upgrades and hard forks Answer: C Explanation: Fabric governance focuses on technical and policy aspects within the network rather than external legal disputes. 85. What is one benefit of building decentralized applications (DApps) on Hyperledger Fabric? A) Centralized control by a single entity B) Enhanced security, transparency, and auditability C) Reduced development time by eliminating smart contracts D) Unlimited transaction speed Answer: B Explanation: DApps built on Fabric benefit from blockchain’s inherent security, transparency, and auditable records.
Explanation: Chaincode is where the business logic resides, automating processes and transactions on the network.
91. What is one key feature of Fabric’s peer nodes? A) They order transactions B) They validate, commit transactions, and maintain the ledger C) They exclusively manage client identities D) They serve as graphical interfaces Answer: B Explanation: Peer nodes are responsible for validating transactions and maintaining an up-to-date ledger. 92. Which statement is true about the block structure in Hyperledger Fabric? A) Blocks contain only encrypted data B) Blocks are composed of headers, transaction data, and metadata C) Blocks are not used in Fabric D) Blocks can be manually edited after creation Answer: B Explanation: Each block contains a header, the list of transactions, and metadata that ensures data integrity. 93. What is the importance of channel policies in Fabric? A) They specify how chaincode is written B) They determine who can join the channel and how transactions are handled C) They define encryption methods D) They are used only for aesthetic purposes Answer: B Explanation: Channel policies are crucial in defining membership and governing how transactions are processed within a channel. 94. Which of the following is a best practice for securing Fabric client applications? A) Hard-coding credentials in the source code B) Using secure storage for identities and enabling TLS communication C) Disabling certificate validation D) Allowing anonymous network access Answer: B Explanation: Securing client applications involves managing credentials securely and ensuring all communications are encrypted. 95. How does Fabric handle chaincode upgrades? A) By completely removing the old chaincode without versioning B) Through a defined lifecycle that supports versioning and controlled upgrades C) By requiring a network reboot D) By changing the endorsement policy only Answer: B
Explanation: Fabric’s chaincode lifecycle includes versioning and a formal upgrade process to ensure a smooth transition.
96. What is the purpose of generating and enrolling identities with Fabric-CA? A) To increase transaction processing speed B) To authenticate and authorize network participants C) To compile chaincode automatically D) To disable network security Answer: B Explanation: Generating and enrolling identities ensures that only authorized participants can interact with the network. 97. Which of the following best describes the role of Access Control Lists (ACLs) in Fabric? A) They manage the ordering of transactions B) They define permissions for various network actions C) They compile chaincode D) They generate encryption keys Answer: B Explanation: ACLs determine which identities can perform certain actions within the Fabric network. 98. What is one challenge associated with performance optimization in Fabric networks? A) Configuring dynamic endorsement policies to balance security and throughput B) Removing all chaincode C) Increasing the size of every block indefinitely D) Disabling peer validation Answer: A Explanation: Balancing security with performance often requires tuning endorsement policies and block parameters. 99. How do Fabric logs assist in troubleshooting? A) They provide detailed records of transaction processing and errors B) They only log successful transactions C) They are stored on an external server exclusively D) They replace the need for performance monitoring tools Answer: A Explanation: Fabric logs give administrators detailed insights into network events, making it easier to diagnose issues. 100. Which of the following is a common industry use case for Hyperledger Fabric? A) Social media networking B) Supply chain traceability C) Video streaming D) Desktop publishing Answer: B
