Blockchain Cryptography in Blockchain Questions and Answers

Question 1

In the context of a blockchain transaction, what is the primary role of a user's private key?

Accepted Answer

To generate a digital signature, thereby authorizing the transaction.

Answer

To decrypt messages sent to the user on the network.

Answer

To serve as the user's public address for receiving funds.

Answer

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

Question 2

A developer is choosing a cryptographic hash algorithm for a new blockchain. Which of the following is NOT a critical property of a secure hash function for this purpose?

Accepted Answer

Reversibility

Answer

Pre-image resistance

Answer

Collision resistance

Answer

Deterministic output

Question 3

A financial institution wants to use a blockchain to verify certain properties of its clients' transactions (e.g., that a client has sufficient funds) without revealing the sensitive details of the transactions themselves (e.g., the exact amount or recipient). Which cryptographic technique would be most suitable for this scenario?

Accepted Answer

Zero-Knowledge Proofs (ZKPs)

Answer

Symmetric Encryption

Answer

SHA-256 Hashing

Answer

Multisignature Schemes

Question 4

What is the primary advantage of using Elliptic Curve Cryptography (ECC) for digital signatures in blockchain compared to older algorithms like RSA?

Accepted Answer

It provides a similar level of security with significantly smaller key sizes.

Answer

It is completely resistant to attacks from quantum computers.

Answer

It allows for the encryption of larger amounts of data within a single transaction.

Answer

It is simpler to implement and requires less rigorous mathematical understanding.

Question 5

In a Bitcoin block, thousands of transactions are summarized into a single 32-byte hash value that is included in the block header. What is the name of the data structure used to achieve this efficient and verifiable summary?

Accepted Answer

Merkle Tree

Answer

Hash Chain

Answer

Patricia Trie

Answer

Bloom Filter

Question 6

When a node on a blockchain network receives a new transaction, it uses the sender's public key to perform a critical cryptographic operation. What is the purpose of this operation?

Accepted Answer

To verify the digital signature attached to the transaction.

Answer

To encrypt the transaction so no one else can see the details.

Answer

To determine the sender's remaining account balance.

Answer

To generate a new private key for the sender for future transactions.