FREE Blockchain Developer Blockchain Fundamentals and Cryptography Questions and Answers

Question 1

In public-key cryptography, which key is used to create a digital signature, and which key is used to verify it?

Accepted Answer

The sender's private key creates the signature, and the sender's public key verifies it.

Answer

The sender's public key creates the signature, and the sender's private key verifies it.

Answer

The receiver's private key creates the signature, and the receiver's public key verifies it.

Answer

A shared secret key is used for both creation and verification.

Question 2

A development team is building a decentralized application (dApp) that requires low transaction fees, high throughput, and the ability to handle complex computations. The consensus mechanism should also be energy-efficient. Which consensus algorithm would be the most suitable choice?

Accepted Answer

Proof of Stake (PoS)

Answer

Proof of Work (PoW)

Answer

Proof of Authority (PoA)

Answer

Proof of Burn (PoB)

Question 3

Which of the following BEST describes the concept of 'immutability' in the context of a blockchain?

Accepted Answer

Once a transaction is recorded in a block and added to the chain, it is computationally infeasible to alter or delete it.

Answer

Once a block is added to the chain, it can only be altered by a majority of network participants.

Answer

Transactions are encrypted and cannot be read by unauthorized parties.

Answer

The blockchain is stored on a single, secure server to prevent data loss.

Question 4

What is the primary function of a hashing algorithm, such as SHA-256, within a blockchain?

Accepted Answer

To generate a unique, fixed-size output (a hash) from a variable-size input, ensuring data integrity.

Answer

To encrypt transaction data so that only the recipient can read it.

Answer

To digitally sign transactions on behalf of the user.

Answer

To determine the order of transactions within a block.

Question 5

A consortium of shipping companies wants to create a shared, permissioned ledger to track cargo movements. They require a system where only pre-approved participants can join the network and validate transactions. Which type of blockchain architecture would be most appropriate for this scenario?

Accepted Answer

Consortium Blockchain

Answer

Public Blockchain

Answer

Private Blockchain

Answer

Hybrid Blockchain

Question 6

What is a Merkle Tree, and what is its primary benefit in a blockchain?

Accepted Answer

A tree structure of cryptographic hashes of transactions that allows for efficient and secure verification of transaction content.

Answer

A data structure that organizes user accounts, making wallet lookups more efficient.

Answer

A governance model for voting on protocol upgrades.

Answer

A type of consensus algorithm that relies on a hierarchy of nodes.