Lesson 1 Introduction to Blockchain

What is the main purpose of using "hash functions" in blockchain technology?

• To authenticate the identity of parties

• To create a persistent, tamper-evident record

• To store the ledger across a peer-to-peer network

• To execute the terms of a contract automatically

What will happen to a block's hash value if even a single character in its data is changed?

• The hash value will stay the same

• The hash value will change slightly

• The function will produce a totally unrelated hash value

• The function will return an error message

Blockchain technology uses Public Key Infrastructure (PKI) for what purpose?

• Identity authentication

• Data integrity

• Distributed storage

• Transaction grouping

In PKI, which key must users never reveal to others?

• The public key

• The private key

• Both public and private key

• The session key

What is the term for a ledger that is stored in a distributed manner across a peer-to-peer network?

• A centralised ledger

• Distributed Ledger Technology (DLT)

• A permissioned system

• A smart contract ledger

In an open, permissionless platform like Bitcoin, who is responsible for storing a local copy of the blockchain?

• Users

• Miners

• Nodes

• A Trusted Third Party (TTP)

Who is responsible for assembling transactions into new blocks on the Bitcoin network?

• Nodes

• Miners

• Users

• Developers

The consensus protocol for Bitcoin requires miners to solve a computationally difficult puzzle, which is known as?

• Proof of Stake

• Proof of Identity

• Proof of Work

• Proof of Bitcoin

What is the name for an attack on a PoW blockchain as attacker gathers more computational power than the rest

• Double-Spending Attack

• Sybil Attack

• 51% Attack

• Denial of Service (DoS) Attack

In a closed, private blockchain, who is typically responsible for acting as the node and miner?

• Any user who downloads the software

• A large group of anonymous miners

• The core software developers

• A single Trusted Third Party (TTP) or a small group of trusted nodes