Blockchain Developer Test 3 — Questions and Answers
Question 1: Who are miners?
- A person digging golds
- Computers that process and verify Blockchain transactions (Correct answer)
- A person calculating transactions
- Uncertainty blockchain
Correct answer: Computers that process and verify Blockchain transactions
In the context of blockchain, 'miners' are specialized computers (or individuals operating them) that perform the computational work required to verify and validate transactions. They bundle these transactions into new blocks and add them to the blockchain, securing the network. As a reward for their efforts, successful miners receive newly minted cryptocurrency and transaction fees.
Question 2: What does the acronym P2P mean?
- Person to Person
- Peer to Peer
- Password to Password (Correct answer)
- Passcode to Passcode
Correct answer: Password to Password
P2P stands for Peer-to-Peer. In a P2P network, participants (peers) interact directly with each other without the need for a central server or authority. Blockchain technology, including Bitcoin, is built upon a P2P architecture, allowing transactions and data to be shared and validated directly among network nodes, fostering decentralization.
Question 3: How are Blockchain's blocks connected?
- Move on to the following block
- To the previous block in reverse (Correct answer)
- Both
- None of them
Correct answer: To the previous block in reverse
Blockchain blocks are connected chronologically using cryptographic hashes. Each new block contains a unique hash of its own data and a hash pointer to the previous block in the chain. This creates an unbreakable link, ensuring that any alteration to an earlier block would change its hash, invalidating all subsequent blocks and making tampering easily detectable.
Question 4: Which of the following attributes prevents Bitcoin from being anonymous?
- All transactions are tracked using analytical technology on a worldwide transparent ledger. (Correct answer)
- A user's social security number can be used to link bitcoins to them.
- IP addresses are used to create bitcoin addresses.
- Transactions made by Bitcoin users cannot be tracked by anyone.
Correct answer: All transactions are tracked using analytical technology on a worldwide transparent ledger.
While Bitcoin offers pseudonymity (users are identified by addresses, not names), it is not truly anonymous because all transactions are recorded on a public, transparent ledger. This worldwide ledger can be analyzed using specialized tools to trace transaction flows and potentially link addresses to real-world identities, especially when funds interact with regulated exchanges.
Question 5: Which members of this blockchain network do B2B transactions?
- Controller
- Blockchain User (Correct answer)
- Assurance Authority
- Ethereum Developer
Correct answer: Blockchain User
In a blockchain network, B2B (Business-to-Business) transactions are performed by 'Blockchain Users,' which is a broad term encompassing businesses, organizations, or individuals interacting with the network. These users initiate and participate in transactions that are then recorded and validated on the distributed ledger, facilitating secure and transparent business interactions.
Question 6: Which of the following is not a Permissioned Blockchain characteristic?
- Evidence of Stake
- All participants have access at the same level (Correct answer)
- Low cost per transaction
- Dependable environment
Correct answer: All participants have access at the same level
A characteristic that is NOT typical of a permissioned blockchain is that all participants have access at the same level. Permissioned blockchains, by definition, restrict who can participate and often implement tiered access levels and roles. This contrasts with public, permissionless blockchains where all participants typically have equal access to the ledger.
Question 7: Which of the subsequent programs starts a transaction?
- Coding
- Chaincode (Correct answer)
- B2B
- Client Software
Correct answer: Chaincode
In many blockchain platforms, particularly Hyperledger Fabric, 'chaincode' (also known as a smart contract) is the program that defines and executes transactions. When a client application invokes a chaincode function, it initiates a transaction that alters the ledger state according to the predefined business logic, ensuring consistent and automated execution.
Question 8: Which of the following is a file exported after packaging the Business Network Definition to be deployed somewhere?
- Text file (.txt)
- Script File (.js)
- Business Network Archive (.bna) (Correct answer)
- Portable Document Format (.pdf)
Correct answer: Business Network Archive (.bna)
In Hyperledger Composer, a 'Business Network Archive' (.bna) file is the deployable package that contains the entire definition of a business network. This includes the model files, script files (logic), access control rules, and query definitions, all bundled together for easy deployment onto a Hyperledger Fabric runtime.
Question 9: One example of asymmetric encryption is which of the following?
- AES
- RSA (Correct answer)
- Triple DES
- BBA
Correct answer: RSA
RSA (Rivest–Shamir–Adleman) is a widely used public-key cryptosystem, making it a prime example of asymmetric encryption. Asymmetric encryption uses a pair of mathematically linked keys—a public key for encryption and a private key for decryption. This contrasts with symmetric encryption, which uses a single key for both operations.
Question 10: What does ScriptPubKey mean?
- Locking script (Correct answer)
- Unlocking script
- Output script
- Input script
Correct answer: Locking script
In Bitcoin, ScriptPubKey refers to the 'locking script' or output script within a transaction. This script defines the conditions that must be met for the bitcoins in that transaction output to be spent. It essentially 'locks' the funds, specifying requirements like a signature from a particular public key to unlock them.
Question 11: Which of the following can be plugged into Hyperledger?
- Coding
- Consensus mechanism (Correct answer)
- Liquidation
- All the options are correct
Correct answer: Consensus mechanism
Hyperledger is an umbrella project for modular blockchain frameworks, and one of its key features is the ability to plug in different consensus mechanisms. This flexibility allows developers to choose the most suitable consensus algorithm (e.g., PBFT, Raft) for their specific application and network requirements, rather than being restricted to a single one.
Blockchain Developer Test 3
Who are miners?