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Question 1.Which of the following best describes a Distributed Ledger Technology (DLT)? A) A centralized database managed by a single authority B) A peer-to-peer network where each participant stores a copy of the ledger C) A cloud-based file storage system D) A blockchain that only records cryptocurrency transactions Answer: B Explanation: DLT is a decentralized system where every node maintains a synchronized copy of the ledger, ensuring transparency and resilience without a central authority. Question 2.What was the primary motivation behind the creation of the Quorum blockchain? A) To enable anonymous public transactions B) To provide a permissioned, private version of Ethereum for enterprises C) To replace Bitcoin’s proof-of-work with proof-of-stake D) To create a new cryptocurrency for retail investors Answer: B Explanation: Quorum was forked from Ethereum to meet enterprise requirements such as privacy, permissioning, and higher transaction throughput. Question 3.In the context of blockchain, what is a Merkle Tree used for? A) Storing smart contract code B) Validating the integrity of a large set of transactions efficiently C) Managing node consensus D) Generating private keys for accounts Answer: B
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Explanation: Merkle Trees allow a compact representation of many hashes, enabling quick verification that a transaction belongs to a block without revealing all data. Question 4.How does a centralized network differ from a decentralized network? A) Centralized networks have no single point of failure B) Decentralized networks rely on a single trusted authority C) Centralized networks store data on many nodes equally D) Decentralized networks distribute control among multiple independent nodes Answer: D Explanation: In a decentralized network, control and data are spread across many independent nodes, reducing reliance on a single authority. Question 5.What is the primary function of the Ethereum Virtual Machine (EVM)? A) To mine new Ether tokens B) To execute smart contract bytecode in a deterministic manner across all nodes C) To store user private keys D) To manage network routing protocols Answer: B Explanation: The EVM provides a sandboxed environment that runs compiled Solidity code consistently on every Ethereum node. Question 6.Which account type can initiate a transaction without containing any contract code? A) Contract Account B) Externally Owned Account (EOA) C) Multisig Account D) DAO Account
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D) To set the transaction’s timestamp Answer: B Explanation: privateFor defines the recipient nodes that will receive and decrypt the encrypted private payload. Question 10.Which component of Quorum is responsible for encrypting and decrypting private transaction payloads? A) Geth node B) Tessera (or Constellation) privacy manager C) Raft consensus engine D) Block explorer UI Answer: B Explanation: Tessera acts as the privacy manager, handling encryption, decryption, and storage of private transaction data. Question 11.What does the term “Public State” refer to in Quorum’s data model? A) The encrypted private data stored off-chain B) The portion of the world state visible to all participants, similar to Ethereum’s state trie C) The list of validator nodes in the network D) The configuration file for network permissioning Answer: B Explanation: Public State is the globally visible state that all nodes maintain, mirroring the Ethereum world state. Question 12.How does Quorum’s “Private State” differ from its Public State? A) Private State is stored on a separate blockchain
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B) Private State holds encrypted data that only designated participants can read C) Private State contains transaction receipts only D) Private State is used for mining rewards distribution Answer: B Explanation: Private State stores data that is only accessible to the parties specified in the privateFor field, keeping it confidential. Question 13.What is the main advantage of Raft consensus over Proof-of-Work in a permissioned setting? A) Raft provides anonymity for all nodes B) Raft achieves faster finality with lower computational overhead C) Raft requires a large number of miners to secure the network D) Raft automatically creates new tokens as rewards Answer: B Explanation: Raft is a leader-based protocol that reaches consensus quickly without the intensive hashing required by PoW. Question 14.In the context of Raft, what does “Crash Fault Tolerance” (CFT) mean? A) The system can tolerate any number of malicious nodes B) The system can continue operating as long as a majority of nodes are alive and responsive C) The system can recover from double-spending attacks automatically D) The system can function without any network communication Answer: B Explanation: CFT ensures the network remains functional despite some nodes crashing, provided a quorum (majority) remains.
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Explanation: IBFT uses an on-chain governance mechanism where existing validators vote to accept new validators. Question 18.What was the original consensus mechanism used by early versions of Quorum before IBFT and Raft? A) QuorumChain B) Proof-of-Authority C) Delegated Proof-of-Stake D) Tendermint Answer: A Explanation: QuorumChain was a voting-based consensus introduced in early Quorum releases and later superseded. Question 19.What file controls which nodes are allowed to connect to a Quorum network at the network layer? A) permissioned-nodes.json B) genesis.json C) static-nodes.json D) quorum-config.yaml Answer: A Explanation: permissioned-nodes.json lists node enode URLs that are permitted to establish P2P connections. Question 20.How can on-chain permissioning be implemented in Quorum? A) By editing the static-nodes.json file on each node B) By deploying a smart contract that maintains an allow-list of node addresses C) By configuring the operating system firewall
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D) By using a separate VPN for network traffic Answer: B Explanation: On-chain permissioning uses a contract to store and enforce node access rules, enabling dynamic governance. Question 21.What does RBAC stand for in the context of Quorum consortium governance? A) Randomized Block Access Control B) Role-Based Access Control C) Recursive Byzantine Agreement Consensus D) Resource-Based Allocation Cache Answer: B Explanation: RBAC assigns permissions based on defined roles (e.g., admin, member) to manage access to network functions. Question 22.Which tool is commonly used to generate a genesis block for a private Quorum network? A) geth init B) quorum-genesis C) tessera-setup D) docker-compose Answer: A Explanation: geth init processes a genesis JSON file to create the initial block and state for a new network. Question 23.What is the purpose of the Tessera key pair generated during network setup?
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Explanation: ZSL leverages zero-knowledge proofs to allow validation of asset movements without revealing amounts or participants. Question 26.In a Quorum network using Raft, how many nodes must be online to maintain consensus for a network of 5 nodes? A) 1 B) 2 C) 3 D) 5 Answer: C Explanation: Raft requires a majority (⌊n/2⌋ + 1) of nodes to be operational; for 5 nodes, at least 3 must be online. Question 27.What is the primary role of the “Enclave” in Quorum’s architecture? A) To store the blockchain data on disk B) To perform cryptographic operations in an isolated, tamper-resistant environment C) To manage peer discovery and network topology D) To execute smart contracts on behalf of nodes Answer: B Explanation: The Enclave isolates key material and performs encryption/decryption, protecting sensitive operations from the host OS. Question 28.What does the “privateStateRoot” field in a block header represent? A) The hash of the public state trie B) The root hash of the trie containing private state data for that block C) The address of the block proposer
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D) The total gas used in the block Answer: B Explanation: privateStateRoot points to the Merkle-Patricia trie that stores private key-value pairs visible only to authorized participants. Question 29.How does Quorum ensure that private transaction payloads are only stored on authorized nodes? A) By broadcasting the payload to all nodes and letting each node decide to ignore it B) By using a distributed file system that replicates data to every node C) By sending the encrypted payload directly to the designated recipients via the privacy manager, which stores it locally D) By embedding the payload in the smart contract code itself Answer: C Explanation: The privacy manager (Tessera) forwards encrypted payloads only to the nodes listed in privateFor, and each such node stores the payload locally. Question 30.What is the effect of calling selfdestruct(address payable recipient) in a Solidity contract? A) It pauses the contract until manually resumed B) It permanently removes the contract code and sends any remaining Ether to recipient C) It upgrades the contract to a new version automatically D) It changes the contract’s address to a new one Answer: B Explanation: selfdestruct deletes the contract from the state and transfers its balance to the specified address.
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Question 34.What is the purpose of the static-nodes.json file in a Quorum network? A) To list the privacy manager endpoints B) To define the set of bootnodes that a node will connect to at startup C) To store the genesis block configuration D) To manage on-chain permission contracts Answer: B Explanation: static-nodes.json contains enode URLs of peers that the node will always attempt to maintain connections with. Question 35.How does Quorum handle transaction ordering in the presence of private transactions? A) Private transactions are ordered globally like public ones B) Private transactions are ordered only among the participants that share the private payload C) Private transactions are not ordered at all; they are processed asynchronously D) Private transactions are placed in a separate blockchain Answer: B Explanation: Ordering for private transactions is deterministic only among the nodes that receive the encrypted payload; other nodes see only a placeholder hash. Question 36.What is the main security benefit of using asymmetric encryption for private transaction payloads? A) It reduces the size of the payload on the network B) It allows any node to decrypt the payload without a shared secret C) Only the intended recipient, possessing the matching private key, can decrypt the payload
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D) It eliminates the need for a privacy manager altogether Answer: C Explanation: Asymmetric encryption ensures confidentiality because only the holder of the corresponding private key can decrypt the data. Question 37.What does the term “gas limit” specify for a transaction? A) The maximum amount of Ether a transaction can transfer B) The maximum computational steps the transaction is allowed to consume C) The deadline after which the transaction expires D) The number of nodes that must sign the transaction Answer: B Explanation: Gas limit caps the amount of gas (i.e., computational effort) a transaction may use, preventing runaway execution. Question 38.What is a “validator” in the context of IBFT? A) A node that mines new blocks using PoW B) A node that participates in the three-phase commit to approve blocks C) A smart contract that validates user input D) A client that only reads blockchain data Answer: B Explanation: Validators are the participants that run the IBFT protocol, voting on block proposals during pre-prepare, prepare, and commit phases. Question 39.How can a Quorum node be configured to reject connections from unauthorized peers? A) By setting networkId to a unique value B) By editing permissioned-nodes.json to include only allowed enode URLs
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A) The address of the permissioning smart contract on-chain B) The HTTP endpoint of the privacy manager (Tessera) for that node C) The node’s public IP address for peer discovery D) The location of the genesis file Answer: B Explanation: --permaddr points the node to its local Tessera instance, enabling private transaction handling. Question 43.How does Quorum achieve deterministic finality for private transactions? A) By using PoW difficulty adjustments B) By relying on the underlying Raft or IBFT consensus which finalizes blocks instantly once a quorum signs C) By waiting for a 24-hour confirmation window D) By requiring multiple signatures from unrelated nodes Answer: B Explanation: Both Raft and IBFT provide immediate finality once the required number of validators have approved a block. Question 44.What is the purpose of the --raftport option? A) To set the port used for private transaction encryption B) To specify the TCP port on which the Raft consensus messages are exchanged C) To define the HTTP RPC listening port D) To configure the port for the block explorer UI Answer: B Explanation: --raftport designates the network port for Raft’s internal communication between leader and followers.
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Question 45.Which of the following is a valid reason to choose Quorum over Hyperledger Fabric for a new project? A) Need for native support of zero-knowledge proofs and private state trie B) Requirement for a completely permissionless public network C) Preference for a programming model based on chaincode written in Go only D) Desire to avoid any on-chain smart contract capability Answer: A Explanation: Quorum’s integration of private state, ZSL, and EVM compatibility makes it attractive for use cases needing confidential smart contracts. Question 46.What does the --nodiscover flag do when starting a Quorum node? A) Enables automatic discovery of new peers via UDP B) Disables the node’s ability to discover or be discovered by other peers C) Forces the node to mine blocks continuously D) Activates the privacy manager automatically Answer: B Explanation: --nodiscover turns off the discovery protocol, limiting connections to those explicitly defined. Question 47.In Quorum, what is the role of the “block explorer” tool? A) To generate private keys for nodes B) To provide a UI for viewing public and private transaction details, block contents, and network status C) To replace the need for RPC endpoints D) To mine new blocks in a Raft network Answer: B
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D) It forces all transactions to be public Answer: B Explanation: Setting privateState to true signals the client to allocate a private state database for handling confidential data. Question 51.Which cryptographic primitive does Tessera primarily use for encrypting private payloads? A) SHA-256 hashing only B) AES-256 symmetric encryption combined with RSA/ECDSA for key exchange C) MD5 hashing for speed D) Elliptic Curve Diffie-Hellman without any symmetric layer Answer: B Explanation: Tessera encrypts payloads with a symmetric AES key, which is then encrypted using the recipients’ public keys (RSA/ECDSA) for secure distribution. Question 52.What is a “gas-price oracle” used for in a Quorum network? A) To automatically set the gas price based on network demand, even though Quorum may set it to zero for private txs B) To mine new blocks faster C) To encrypt private payloads D) To manage node permissioning Answer: A Explanation: An oracle can suggest appropriate gas prices; in permissioned settings this may be optional but still useful for accounting. Question 53.How does the quorum_rawTransaction RPC method differ from the standard eth_sendRawTransaction?
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A) It automatically signs the transaction with the node’s private key B) It allows inclusion of private transaction fields such as privateFor and privateFrom C) It bypasses all consensus checks D) It sends the transaction directly to the block explorer UI Answer: B Explanation: quorum_rawTransaction extends the standard method to handle Quorum-specific privacy metadata. Question 54.What is the primary difference between the “public state trie” and the “private state trie”? A) The public trie stores only contract bytecode, while the private trie stores all account balances B) The public trie is replicated across all nodes; the private trie is only stored by nodes that receive the private payloads C) The public trie uses a different hashing algorithm than the private trie D) The private trie is stored off-chain in a separate database Answer: B Explanation: Public state is globally replicated; private state remains confined to participants of a private transaction. Question 55.In an IBFT network with 4 validators, how many faulty (Byzantine) nodes can the network tolerate while still reaching consensus? A) 0 B) 1 C) 2 D) 3 Answer: B
