Blockchain Core Concepts 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?

Accepted Answer

Immutability

Answer

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?

Accepted Answer

Permissioned (Private) Blockchain

Answer

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?

Accepted Answer

To allow all nodes on the network to agree on the validity of transactions and the state of the ledger.

Answer

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?

Accepted Answer

By converting variable-length transaction data into a unique, fixed-length string, making tampering evident.

Answer

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?

Accepted Answer

Smart Contract

Answer

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.

Blockchain Practice Test

Blockchain Practice Test

Blockchain Core Concepts Questions and Answers