What is a blockchain?

• A type of cryptocurrency

• A centralized database

• A distributed and immutable ledger

• A cloud storage service

What does a block in a blockchain contain?

• User passwords and private keys

• A list of transactions, a timestamp, and a hash

• Physical hardware data

• Bank account details

What is the role of cryptography in blockchain?

• To encrypt the entire blockchain

• To ensure data privacy and secure transactions

• To mine cryptocurrency

• To create internet protocols

What is a key feature of blockchain that ensures security?

• Centralized control

• Tamper-resistant ledger

• High-speed processing

• Unlimited storage capacity

What is the consensus mechanism in blockchain?

• A method for converting cryptocurrencies

• A process by which participants agree on the state of the ledger

• A protocol for encrypting data

Which of the following is a popular consensus mechanism in blockchain?

• Data Validation Protocol (DVP)

• Proof of Work (PoW)

• Transaction Evaluation System (TES)

• Hash Authorization Protocol (HAP)

What is a "smart contract"?

• A contract with legal backing

• A self-executing agreement with terms directly written into code

• A document signed digitally

• An AI-powered legal document

What is the primary difference between public and private blockchains?

• Public blockchains are free to use, while private ones are paid.

• Public blockchains are decentralized, and private blockchains are controlled by a specific entity.

• Public blockchains are faster than private blockchains.

• Private blockchains do not use cryptography.

What is the role of miners in a blockchain?

• To secure the network and validate transactions by solving cryptographic puzzles

• To delete invalid transactions

• To create new blockchain nodes

• To distribute rewards to users

What is the "hash" in blockchain technology?

• A unique identifier for a block based on its contents

• A type of encryption key

• The address of a blockchain wallet

• A record of unsuccessful transactions