Blockchain Core Concepts Questions and Answers — Questions and Answers
Question 1: Which of the following core blockchain concepts ensures that once a transaction is recorded on the ledger, it cannot be altered or deleted?
- Decentralization
- Immutability (Correct answer)
- Tokenization
- Scalability
Correct answer: Immutability
Immutability is the fundamental property of blockchain that ensures data, once written to the ledger, is permanent and cannot be changed. This is achieved through cryptographic hashing, where each block is linked to the previous one, creating a secure chain. Any attempt to alter a block would change its hash, which would invalidate all subsequent blocks.
Question 2: A supply chain consortium wants to build a blockchain solution to track goods from manufacturer to retailer. They need to ensure that only authorized participants can view and add transactions. Which type of blockchain would be most suitable for this scenario?
- Public Blockchain
- Hybrid Blockchain
- Permissioned (Private) Blockchain (Correct answer)
- Sidechain
Correct answer: Permissioned (Private) Blockchain
A permissioned or private blockchain is the most suitable choice because it restricts access to a specific group of authorized participants. This allows the consortium to maintain confidentiality and control over who can interact with the supply chain data, which is a common requirement for enterprise-level applications.
Question 3: What is the primary function of a consensus mechanism in a decentralized blockchain network?
- To encrypt transaction data for privacy.
- To execute the code within a smart contract.
- To allow all nodes on the network to agree on the validity of transactions and the state of the ledger. (Correct answer)
- To generate public and private keys for users.
Correct answer: To allow all nodes on the network to agree on the validity of transactions and the state of the ledger.
A consensus mechanism is a set of rules that enables participants in a decentralized network to agree on the current state of the ledger without a central authority. It ensures that all transactions are validated and that all nodes have a consistent view of the blockchain, preventing issues like double-spending.
Question 4: How does cryptographic hashing contribute to the security and integrity of a blockchain?
- By converting variable-length transaction data into a unique, fixed-length string, making tampering evident. (Correct answer)
- By hiding the identities of the transaction participants.
- By determining the monetary value of a cryptocurrency.
- By automatically executing the terms of an agreement.
Correct answer: By converting variable-length transaction data into a unique, fixed-length string, making tampering evident.
Cryptographic hash functions take an input of any size and produce a unique, fixed-size output called a hash. In a blockchain, each block contains the hash of the previous block. If any data in a block is altered, its hash will change, which in turn changes the hash of every subsequent block, making any tampering immediately obvious throughout the network.
Question 5: A developer creates a program that automatically releases payment to a freelance worker from an escrow account as soon as the project is marked 'complete' on the platform. What blockchain concept does this program exemplify?
- Proof of Work
- Smart Contract (Correct answer)
- Forking
- Merkle Tree
Correct answer: Smart Contract
This scenario describes a smart contract. A smart contract is a self-executing contract with the terms of the agreement directly written into code. It automatically executes actions, like releasing a payment, when predefined conditions are met, eliminating the need for a third-party intermediary.
Question 6: In a Proof of Work (PoW) consensus mechanism, what is the primary role of 'miners'?
- To vote on network governance proposals.
- To stake their cryptocurrency to validate transactions.
- To audit the financial statements of the blockchain project.
- To compete to solve a complex mathematical puzzle to validate transactions and create new blocks. (Correct answer)
Correct answer: To compete to solve a complex mathematical puzzle to validate transactions and create new blocks.
In a Proof of Work system, miners use computational power to solve a complex mathematical problem. The first miner to solve the puzzle gets to add the next block of transactions to the blockchain and is rewarded for their 'work'. This process secures the network and validates transactions.
Blockchain Core Concepts Questions and Answers
Which of the following core blockchain concepts ensures that once a transaction is recorded on the ledger, it cannot be altered or deleted?