Blockchain MCQs with Answers

1 .

What is a blockchain?

A)

A Currency

B)

A centralized ledger

C)

A type of cryptocurrency

D)

A distributed ledger on a peer to peer network

Correct Answer : A distributed ledger on a peer to peer network

Explanation : A Blockchain is a constantly growing ledger(file) that keeps a permanent record of all the transactions that have taken place, in a secure, chronological, and immutable way. It can be used for the secure transfer of money, property, contracts, etc. without requiring a third-party intermediary like bank or government.

Blockchain is the backbone of the most famous cryptocurrency named Bitcoin. It is a peer to peer electronic cash system and a decentralized network which allows users to make transactions directly without the involvement of third-party to manage the exchange of funds..

Source : F T L

2 .

Who first proposed a blockchain-like protocol?

A)

David Chaum

B)

Dave Bayer

C)

Stuart Haber

D)

W. Scott Stornetta

Correct Answer : David Chaum

Explanation : Cryptographer David Chaum first proposed a blockchain-like protocol in his 1982 dissertation "Computer Systems Established, Maintained, and Trusted by Mutually Suspicious Groups.

3 .

The first blockchain was conceptualized by a person (or group of people) known as Satoshi Nakamoto in?

A)

2006

B)

2007

C)

2008

D)

2009

Correct Answer : 2008

Explanation : The blockchain was popularized by a person (or group of people) using the name Satoshi Nakamoto in 2008 to serve as the public transaction ledger of the cryptocurrency bitcoin, based on work by Stuart Haber, W. Scott Stornetta, and Dave Bayer. The identity of Satoshi Nakamoto remains unknown to date. The implementation of the blockchain within bitcoin made it the first digital currency to solve the double-spending problem without the need of a trusted authority or central server.

4 .

Where do you store your cryptocurrency?

A)

Pocket

B)

Wallet

C)

Exchange

D)

Bank account

Correct Answer : Wallet

Explanation : Just the way we keep cash or cards in a physical wallet, bitcoins are also stored in a wallet—a digital wallet. The digital wallet can be hardware-based or web-based. The wallet can also reside on a mobile device, on a computer desktop, or kept safe by printing the private keys and addresses used for access on paper.

5 .

Which of these US states introduced the BitLicense regulation for cryptocurrency companies?

A)

Texas

B)

New York

C)

California

D)

Washington

Correct Answer : New York

6 .

Blockchain is a peer-to-peer _____________ distributed ledger technology that makes the records of any digital asset transparent and unchangeable.

A)

Secure

B)

Popular

C)

Demanding

D)

Decentralized

Correct Answer : Decentralized

Explanation : Blockchain is a peer-to-peer decentralized distributed ledger technology that makes the records of any digital asset transparent and unchangeable and works without involving any third-party intermediary.

7 .

What does P2P stand for?

A)

Peer to Peer

B)

Product to Product

C)

Password to Password

D)

Private Key to Public Key

Correct Answer : Peer to Peer

8 .

What is a node?

A)

A Blockchain

B)

An exchange

C)

A type of cryptocurrency

D)

A computer on a Blockchain network

Correct Answer : A computer on a Blockchain network

9 .

Who created Bitcoin?

A)

Elon Musk

B)

Warren Buffett

C)

Satoshi Nakamoto

D)

Mark Zuckerberg

Correct Answer : Satoshi Nakamoto

Explanation : Satoshi Nakamoto is the pseudonym who penned the original Bitcoin whitepaper and is the identity credited with inventing Bitcoin itself.

10 .

Which of the following statement is true about blockchain?

A)

A blockchain is a decentralized, distributed, and oftentimes public, digital ledger consisting of records called blocks.

B)

A blockchain database is managed autonomously using a peer-to-peer network and a distributed timestamping server.

C)

A blockchain has been described as a value-exchange protocol.

D)

All of the above statements are true

Correct Answer : All of the above statements are true

11 .

Blocks hold batches of valid transactions that are hashed and encoded into a?

A)

temporary fork

B)

merkle tree

C)

genesis block

D)

cryptographic hash

Correct Answer : merkle tree

Explanation : Blocks hold batches of valid transactions that are hashed and encoded into a Merkle tree.

12 .

A blockchain is a type of?

A)

Database

B)

View

C)

Table

D)

Object

Correct Answer : Database

13 .

Where is the LEAST SAFE place to keep your cryptocurrency?

A)

On a hot wallet

B)

On an exchange

C)

In your pocket

D)

At your work desk

Correct Answer : On an exchange

14 .

What does UTXO stand for?

A)

United Transaction Office

B)

Union of Texas Operations

C)

Unspent Transaction Output

D)

United Texan Xerox Organization

Correct Answer : Unspent Transaction Output

Explanation : An Unspent Transaction Output (UTXO) is the technical term for the amount of digital currency that remains after a cryptocurrency transaction.

15 .

Who invented Merkle Trees?

A)

Nick Szabo

B)

Vitalik Buterin

C)

Ralph Wiggum

D)

Ralph Merkle

Correct Answer : Ralph Merkle

Explanation : Merkle trees were invented by Ralph Merkle in 1988 in an attempt to construct better digital signatures. You can read Merkle's original paper or you can read this easier paper.

16 .

Which site run by Ross Ulbricht was closed by the FBI for letting people buy drugs with Bitcoin?

A)

Dark Alley

B)

Silk Street

C)

Silk Road

D)

Lace Place

Correct Answer : Silk Road

Explanation : Silk Road 2.0 shut down by FBI and Europol on 6 November 2014. In October 2013, the Federal Bureau of Investigation (FBI) shut down the website and arrested Ross Ulbricht under charges of being the site's pseudonymous founder "Dread Pirate Roberts".

17 .

Which of the following industry can use blockchain technology for cybersecurity?

A)

Logistics

B)

Healthcare

C)

Critical infrastructure

D)

All of the Above

Correct Answer : All of the Above

18 .

What is the term for when a blockchain splits?

A)

A fork

B)

A division

C)

A merger

D)

None of The Above

Correct Answer : A fork

19 .

Blockchain networks are much _____ and deal with no real single point of failure.

A)

Simpler

B)

Easier to scale

C)

Faster

D)

Convenient

Correct Answer : Easier to scale

Explanation : In comparison to a standard centralized network, a decentralized network has several advantages, including greater system reliability and privacy. Furthermore, such networks are far easier to grow and have no single point of failure.

20 .

What is a miner?

A)

A type of blockchain

B)

Computers that validate and process blockchain transactions

C)

A person doing calculations to verify a transaction

D)

An algorithm that predicts the next part of the chain

Correct Answer : Computers that validate and process blockchain transactions

Explanation : Miner is an actor who participates in cryptocurrency transactions, and in turn, plays a crucial role both in creating new cryptocurrencies and in verifying transactions on the blockchain. It adds new blocks to the existing chain, and ensures that these additions are accurate.

21 .

What is a hash function?

A)

A fork

B)

Gas

C)

UTXO

D)

Takes an input of any length and returns a fixed-length string of numbers and letters

Correct Answer : Takes an input of any length and returns a fixed-length string of numbers and letters

22 .

Cryptographic Hash Function transforms an arbitrary length of a fixed length string that act more or less as a Fingerprint of the document

A)

True

B)

False

C)

--

D)

--

Correct Answer : False

23 .

Blockchain can perform user transactions without involving any third-party intermediaries.

A)

Without involving any owned

B)

With the help of the third party

C)

Without involving any third party

D)

Without involving any authenticated

Correct Answer : Without involving any third party

Explanation : A shared ledger, or blockchain, is a system that allows thousands of computers or servers to maintain a single, secure, and immutable record. Without the necessity of third-party intermediaries, blockchain may conduct user transactions. All that is required to conduct transactions is the possession of a wallet.

24 .

Blockchain has ____ versions.

A)

3

B)

4

C)

5

D)

6

Correct Answer : 3

Explanation : Blockchain has three versions.
Blockchain 1.0 : Cryptocurrency.
Blockchain 2.0 : Smart Contracts.
Blockchain 3.0 : DApps.

Source : F T L

25 .

What does a block in a Blockchain have?

A)

Header & Transaction

B)

Bitcoins & Input

C)

Transactions & Bitcoins

D)

Header & Digital ledger

Correct Answer : Header & Transaction

Explanation : The block is made up of a metadata-filled header and a long list of transactions that make up the majority of its size. The typical transaction is at least 250 bytes long, while the average block comprises more than 500 transactions.

26 .

What are the benefits of blockchain technology?

A)

Security & Speed

B)

No hidden fees

C)

Fraud control & Access levels

D)

All of the Above

Correct Answer : All of the Above

27 .

What are the pillars of blockchain technology?

A)

Immutability

B)

Transparency

C)

Decentralization

D)

All of the Above

Correct Answer : All of the Above

28 .

What is the genesis block?

A)

Any block created by the founder

B)

The first block of a Blockchain

C)

The first transaction in each block

D)

The last block created in the Blockchain

Correct Answer : The first block of a Blockchain

Explanation : Since every bitcoin traces its genealogy back to the Genesis Block, also known as Block 0, every other bitcoin block may trace its lineage back to it.

29 .

What is the name of the famous Bitcoin exchange from Japan that collapsed in 2014?

A)

Mt. Gox

B)

Tradehill

C)

Bitstamp

D)

Blockchain.info

Correct Answer : Mt. Gox

Explanation : Mt. Gox. Gox was a bitcoin exchange based in Shibuya, Tokyo, Japan. Launched in July 2010, by 2013 and into 2014 it was handling over 70% of all bitcoin (BTC) transactions worldwide, as the largest bitcoin intermediary and the world's leading bitcoin exchange.

30 .

What does the block in the blockchain consist of?

A)

A Hash point

B)

A Timestamp

C)

Transaction data

D)

All of the above

Correct Answer : All of the above

Explanation : “Each block contains a hash (a digital fingerprint or unique identifier), timestamped batches of recent valid transactions, and the hash of the previous block. The previous block hash links the blocks together and prevents any block from being altered or a block being inserted between two existing blocks.” In theory, the method renders the blockchain tamperproof.

31 .

___ hosts the software needed for transaction initiation, validation, mining, block creation, and smart contract execution.

A)

EVM

B)

Smart Contract

C)

Ethereum full node

D)

External Account

Correct Answer : Ethereum full node

Explanation : Ethereum is a distributed network of computers (known as nodes) that can validate blocks and transaction data by executing software. To "run" a node on your computer, you'll need a client application.

32 .

Where can you buy cryptocurrency?

A)

An exchange

B)

A Bitcoin ATM

C)

A private transaction

D)

All of the above

Correct Answer : All of the above

33 .

Which is NOT a part of asymmetric encryption?

A)

Mining

B)

Public key

C)

Private Key

D)

Passphrase

Correct Answer : Mining

34 .

What does IPFS stand for?

A)

Internet Play Store

B)

InterPlanetary File System

C)

Inter Filing System

D)

Internet Platform for Storage

Correct Answer : InterPlanetary File System

Explanation : The InterPlanetary File System (IPFS) is a protocol and peer-to-peer network for storing and sharing data in a distributed file system. IPFS uses content-addressing to uniquely identify each file in a global namespace connecting all computing devices.

35 .

What is a dApp?

A)

A condiment

B)

A type of blockchain

C)

A type of Cryptocurrency

D)

A decentralized application

Correct Answer : A decentralized application

Explanation : Key Takeaways. Decentralized applications—also known as "dApps" or "dapps"—are digital applications that run on a blockchain network of computers instead of relying on a single computer. Because dApps are decentralized, they are free from the control and interference of a single authority.

36 .

What is the purpose of a nonce?

A)

Follows nouns

B)

A hash function

C)

Prevents double spending

D)

Sends information to the blockchain network

Correct Answer : Prevents double spending

Explanation : A nonce is an abbreviation for "number only used once," which is a number added to a hashed—or encrypted—block in a blockchain that, when rehashed, meets the difficulty level restrictions. The nonce is the number that blockchain miners are solving for, in order to receive cryptocurrency.

37 .

What incentivizes the miners to give correct validation of transactions?

A)

A nonce

B)

More memory

C)

A block reward

D)

Thumbs up from the community

Correct Answer : A block reward

Explanation : For incentivizing the Miner for his correct decisions during the transactions, the sender generally sends some incentives (rewards) in form of the cryptocurrency, in which the transaction takes place. It is generally a small percentage of the whole transaction that takes place.

38 .

What is a Dash Masternode?

A)

A node that provides additional supervisory network services

B)

A single node that runs the whole network

C)

Master of all Dash nodes

D)

Two nodes sharing resources

Correct Answer : A node that provides additional supervisory network services

Explanation : Masternodes are powerful servers backed by collateral held in Dash, and are designed to provide advanced services and governance on the blockchain. Dash has been associated with the concept of masternodes ever since the invention of this novel concept soon after the project started in 2014.

39 .

What characteristic makes blockchain tamper-proof?

A)

VPN

B)

Immutability

C)

Servers

D)

Cryptocurrency

Correct Answer : Immutability

40 .

What is the name of the research paper that brought Bitcoin to the world?

A)

Black Paper

B)

Green Paper

C)

Yellow Paper

D)

White Paper

Correct Answer : White Paper

Explanation : Satoshi Nakamoto is the name used by the presumed pseudonymous person or persons who developed bitcoin, authored the bitcoin white paper, and created and deployed bitcoin's original reference implementation.

41 .

What are sidechains?

A)

Another term for a hash function

B)

Smart Contracts that have forked off the main Blockchain

C)

A parallel network running adjacent to the main blockchain network for additional security

D)

Any mechanism that allows tokens from one blockchain to be securely used within a completely separate Blockchain

Correct Answer : Any mechanism that allows tokens from one blockchain to be securely used within a completely separate Blockchain

Explanation : A sidechain is a separate blockchain which runs in parallel to Ethereum Mainnet and operates independently. It has its own consensus algorithm (e.g. proof-of-authority, Delegated proof-of-stake, Byzantine fault tolerance). It is connected to Mainnet by a two-way bridge.

42 .

When a record is on a blockchain, who can access it?

A)

One person at a time.

B)

Only the people involved in the transaction.

C)

Multiple people simultaneously.

D)

None of the Above

Correct Answer : Multiple people simultaneously.

43 .

Once records are submitted on a blockchain, can they be altered?

A)

Yes – but only within a certain time frame.

B)

No – they cannot be altered.

C)

Yes – the parties can go back in and alter them at any time.

D)

None of the Above

Correct Answer : No – they cannot be altered.

44 .

What is not a ledger type considered by users in Blockchain?

A)

Distributed Ledger

B)

Decentralized Ledger

C)

Both (A) and (B)

D)

None of the Above

Correct Answer : None of the Above

45 .

Bitcoin is based on _________ blockchain.

A)

Public

B)

Private

C)

Permissioned

D)

Public Permissioned

Correct Answer : Public

Explanation : Public blockchain can be used to construct a completely open blockchain, similar to Bitcoin, that allows everyone and everyone to join and contribute to the network.

46 .

BATM stands for _____.

A)

Bitcoin ATM

B)

Blockchain ATM

C)

Broadcast ATM

D)

Bounded Access Transaction Machine

Correct Answer : Bitcoin ATM

Explanation : A Bitcoin ATM (abbreviated as BATM) is a kiosk where a person can purchase Bitcoin using an automated teller machine.

47 .

What is a genesis block?

A)

The 2nd transaction of a Blockchain

B)

The first block after each block halving

C)

The first block of a Blockchain

D)

A famous block that hardcoded a hash of the Book of Genesis onto the blockchain

Correct Answer : The first block of a Blockchain

Explanation : A Genesis Block is the name given to the first block a cryptocurrency, such as Bitcoin, ever mined. A blockchain consists of a series of so-called blocks that are used to store information related to transactions that occur on a blockchain network.

48 .

What powers the Ethereum Virtual Machine?

A)

Ether

B)

Gas

C)

Bitcoin

D)

Block Rewards

Correct Answer : Gas

Explanation : For every instruction implemented on the Ethereum Virtual Machine(EVM), a system that keeps track of execution cost, assigns to the instruction an associated cost in Gas units.

49 .

What is Proof of Stake?

A)

How private keys are made

B)

A certificate needed to use the blockchain

C)

A password needed to access an exchange

D)

A transaction and block verification protocol

Correct Answer : A transaction and block verification protocol

50 .

What is the maximum number of bitcoins that can be created?

A)

15 million

B)

21 million

C)

50 million

D)

There is no maximum

Correct Answer : 21 million

Explanation : When Satoshi Nakamoto created Bitcoin, he installed a strict limit on the number of Bitcoin that could ever exist. There will never be more than 21 million bitcoin. This limit, known as the hard cap, is encoded in Bitcoin's source code and enforced by nodes on the network.

51 .

What is the impact of information leak for an organization?

A)

Loss in profit

B)

Loss of trust in customers

C)

Cut down the reputation of the organization

D)

All of the above

Correct Answer : All of the above

52 .

Smart Contract characteristics do not include:

A)

Alterable

B)

Transparency

C)

Fast and cost-effective

D)

A high degree of accuracy

Correct Answer : Alterable

Explanation : Smart Contracts (SC) are digital code sets designed to make asset transfers easier (including non-digital assets). They are clear, precise, quick, and cost-effective.

53 .

A)

True

B)

False

C)

--

D)

--

Correct Answer : False

Explanation : Bitcoin is a digital currency that is secure thanks to Blockchain technology. Ethereum Blockchain Ethereum uses a blockchain network to perform its operations. Ethereum, a public blockchain network, is increasingly being used to facilitate enterprise transactions needing automatic, rule-based asset transfer, just like all cryptocurrencies.

54 .

For the simple symmetric key example discussed in the lecture, it is easy to derive the secret key from the encrypted data.

A)

True

B)

False

C)

--

D)

--

Correct Answer : True

Explanation : Symmetric encryption, often known as a secret key algorithm, employs only one key: a secret key for message encryption and decoding. It is simple to deduce the secret key from the encrypted data in the simple symmetric key case described in the lecture.

55 .

What type of hash is used when there is a fixed number of items to be hashed, such as the items in a block header, and we are verifying the composite block integrity?

A)

Either

B)

Complex hash

C)

Simple Hash

D)

Tree-structured Hash

Correct Answer : Simple Hash

Explanation : Masking off the bottom m bits to use as an index into a table of size 2 m is a basic hash function. A folding hash code is created by dividing the input into n pieces of m bits each, where 2m is the table size, then combining the sections with a parity-preserving bitwise operation like ADD or XOR.

56 .

What type of hash function is used, when there is a variable number of items to be hashed, such as the many state changes in a block?

A)

Either

B)

Simple Hash

C)

Complex hash

D)

Tree-structured Hash

Correct Answer : Tree-structured Hash

Explanation : In the fields of cryptography and computing science, Hash trees, also known as Merkle trees, are a sort of data structure that stores a tree of summary information about a bigger piece of data, such as a file, and is used to validate its contents. Hash trees are a subset of hash lists, which are themselves subsets of hashing.

57 .

What is the process of creating new bitcoins popularly known as?

A)

Finding

B)

Mining

C)

Panning

D)

Sourcing

Correct Answer : Mining

Explanation : The process of creating bitcoin popularly known as Mining.

58 .

What time did Bitcoin Network Start?

A)

August 2004

B)

November 2008

C)

January 2009

D)

December 2011

Correct Answer : January 2009

Explanation :

On 3 January 2009, the bitcoin network was created when Nakamoto mined the starting block of the chain, known as the genesis block.

White paper : "Bitcoin: A Peer-to-Peer Electronic

Code repository : github.com/bitcoin/bitcoin

Implementation(s) : Bitcoin Core

59 .

The transaction Merkle Tree root value in a Bitcoin block is calculated using,

A)

Hash of transactions

B)

Previous block's hash

C)

Number of transactions

D)

None of the above

Correct Answer : Hash of transactions

Explanation : By hashing together pairs of TXIDs, a Merkle root is generated, which gives you a brief yet unique fingerprint for all the transactions in a block.

60 .

Hash identifying each block in the blockchain is generated using which of the following cryptographic algorithm?

A)

SHA64

B)

SHA128

C)

SHA256

D)

None of the Above

Correct Answer : SHA256

Explanation : SHA 256 is a member of the SHA 2 algorithm family, with SHA standing for Secure Hash Algorithm. It was a joint effort between the National Security Agency and the National Institute of Standards and Technology to introduce a successor to the SHA 1 family, which was slowly losing power against brute force attacks. It was published in 2001.

61 .

Which is/are the applications of Blockchain?

A)

Cross-border payments

B)

Supply chain and logistics monitoring

C)

Anti-money laundering tracking system

D)

All of the Above

Correct Answer : All of the Above

Explanation : Cross-border payments, anti-money laundering tracking systems, supply chain and logistics monitoring, and so on are just a few of the possibilities for blockchain.

62 .

What is a smart contract?

A)

Online contract

B)

Offline contract

C)

Digital contract

D)

Programs stored on a blockchain that run when predetermined conditions are met

Correct Answer : Programs stored on a blockchain that run when predetermined conditions are met

Explanation : A "smart contract" is software that runs on Ethereum's blockchain. It's a collection of code (its functions) and data (its state) that lives on the Ethereum blockchain at a single address. Ethereum accounts come in the form of smart contracts.

63 .

Where is a Blockchain’s central server?

A)

Ordered Node

B)

Where the blockchain is created

C)

There is no central server, it is distributed

D)

Located with the owner of the server

Correct Answer : There is no central server, it is distributed

Explanation : There is no central server in a blockchain, which is a digital distributed ledger of transactions that are recorded and duplicated in real-time throughout a network.

64 .

Transactions per second (TPS) for Proof-of-Work Blockchain are approximate?

A)

7-15 per second

B)

24K per second

C)

175K per second

D)

225K per second

Correct Answer : 7-15 per second

65 .

What does a ledger in blockchain does?

A)

Identification of owners

B)

Mapping between owner and object

C)

Identification of objects owned

D)

None of the Above

Correct Answer : Mapping between owner and object

66 .

First step of Blockchain project implementation is?

A)

Screen idea consideration

B)

Requirement identification

C)

Feasible study on the security

D)

Controlling and monitoring the project

Correct Answer : Requirement identification

67 .

The height of the block is the ____ in the chain between it and the genesis block.

A)

Metadata that is

B)

Merkle tree hash

C)

Size of the memory cache

D)

Number of blocks

Correct Answer : Number of blocks

Explanation : The total number of blocks connected since the genesis block is the block height. The number of blocks between any given block and the genesis block determines its height.

68 .

Blockchain does not provide?

A)

Security

B)

Immutability

C)

Fast transaction time

D)

Fault tolerance

Correct Answer : Fast transaction time

Explanation : When a blockchain's scalability is high, it means the network can handle a large number of transactions quickly. It enables separate accounts to exchange data swiftly, if not immediately, independent of the network traffic.

69 .

What biblical name is given to the first block in blockchain?

A)

Genesis

B)

Ada

C)

Origin

D)

Primal

Correct Answer : Genesis

Explanation : A genesis block (block number 0) is the initial block in a blockchain. This is the sole block in a blockchain that does not include any transactions and does not have a valid reference to a previous block.

Introduction :