Public-Key Cryptography and Blockchain: A Comprehensive Guide for Blockchain Security

Question 1

In a public-key infrastructure (PKI), what is the role of a Certificate Authority (CA)?

Accepted Answer

To issue digital certificates that bind public keys to identities

Answer

To generate and distribute private keys

Answer

To store and manage public keys

Answer

To encrypt and decrypt data

Question 2

Public-key cryptography is widely used in blockchain systems. Which of the following is its primary advantage in this context?

Accepted Answer

Enhanced privacy and transaction security

Answer

Reduced transaction processing time

Answer

Simplified user experience in managing blockchain accounts

Question 3

Public-key cryptography is characterized by:

Accepted Answer

Using distinct keys for encryption and decryption

Answer

Requiring shared keys for communication.

Answer

Being exclusively used for secretive messaging

Question 4

In blockchain, a digital signature serves to:

Accepted Answer

Validate a transaction's authenticity

Answer

Establish connections between blocks

Answer

Encrypt data within a block

Answer

Provide sender anonymity

Question 5

A blockchain explorer's purpose is to:

Accepted Answer

Facilitate blockchain data analysis and exploration

Answer

Create new cryptocurrencies

Answer

Mine new blocks for the blockchain

Answer

Securely store private keys

Question 6

A potential security vulnerability associated with blockchain is:

Accepted Answer

51% Attack

Answer

Cross-Site Scripting (XSS)

Answer

SQL Injection

Question 7

The primary role of consensus mechanisms in blockchain is to:

Accepted Answer

Establish agreement among nodes on transaction validity

Answer

Generate new cryptocurrencies

Answer

Encrypt data in blocks

Question 8

An example of a practical application for blockchain technology is:

Accepted Answer

Supply Chain Management

Answer

Word Processing

Answer

Video Editing

Answer

Web Browsing

Question 9

The distinction between public and private blockchains lies in:

Accepted Answer

Public blockchains are open to all, while private blockchains are restricted to authorized participants

Answer

Public blockchains offer superior security compared to private blockchains

Question 10

A smart contract's purpose is to:

Accepted Answer

Automate contract execution based on predefined conditions

Answer

Securely store private keys

Answer

Encrypt data within blocks

Question 11

Which of the following is a defining characteristic of public-key cryptography?

Accepted Answer

Employing a pair of mathematically linked, but distinct keys.

Answer

Relying on a single encryption key for both encryption and decryption.

Answer

Utilizing centralized servers for key storage.

Answer

Encrypting data multiple times to enhance security.

Question 12

In blockchain systems, what is the primary function of a digital signature?

Accepted Answer

Verifying the authenticity and integrity of a message or transaction.

Answer

Establishing secure communication channels between parties.

Answer

Encrypting sensitive data stored on the blockchain.

Question 13

When managing private keys in blockchain environments, which of the following is considered a best practice?

Accepted Answer

Securely storing private keys offline.

Answer

Storing private keys online without encryption.

Answer

Sharing private keys with trusted individuals or entities.

Answer

Using weak passphrases to protect private keys.

Question 14

How does public-key cryptography contribute to secure communication within blockchain networks?

Accepted Answer

Encrypting messages using the recipient's publicly available key.

Answer

Generating one-time passwords for blockchain access.

Answer

Establishing secure tunnels between nodes.

Question 15

What does blockchain technology offer as a key advantage for storing and managing public keys?

Accepted Answer

Enhanced security and increased resilience due to distributed storage.

Answer

Increased efficiency and reduced costs.

Answer

Simplified key management and distribution processes.

Question 16

Which of the following is a fundamental distinction between symmetric and public-key cryptography?

Accepted Answer

Public-key cryptography employs different keys for encryption and decryption.

Answer

Public-key cryptography offers a higher level of security.

Answer

Public-key cryptography requires computationally more demanding algorithms.

Question 17

What is the term for the process of generating a unique address for a blockchain wallet?

Accepted Answer

Address generation.

Answer

Signature verification.

Answer

Transaction validation.

Answer

Key hashing.

Question 18

How does a hash function contribute to the security of blockchain transactions?

Accepted Answer

It generates a unique and irreversible fingerprint of the transaction data.

Answer

It encrypts the transaction data multiple times.

Answer

It verifies the authenticity of digital signatures.

Question 19

What is the primary purpose of a proof-of-work algorithm in public-key cryptography?

Accepted Answer

Preventing malicious actors from generating forged digital signatures.

Answer

Securely encrypting messages.

Answer

Generating public and private key pairs.

Question 20

How does blockchain technology mitigate the risk of man-in-the-middle attacks?

Accepted Answer

Verifying the authenticity of public keys through distributed consensus mechanisms.

Answer

Implementing two-factor authentication.

Answer

Utilizing robust encryption algorithms.

Question 21

Which of the following statements is **NOT** true about public-key cryptography?

Accepted Answer

It requires both the public and private keys to encrypt and decrypt data.

Answer

It uses a pair of mathematically linked keys.

Answer

It is computationally difficult to break.

Question 22

In a blockchain system, what is the primary function of a digital signature?

Accepted Answer

To verify the authenticity and integrity of a message or transaction.

Answer

To generate unique blockchain addresses.

Answer

To encrypt data stored on the blockchain.

Question 23

What is the most secure approach to managing blockchain wallet keys?

Accepted Answer

Store private keys offline, use multiple wallets, and consider hardware wallets.

Answer

Store keys on multiple online platforms.

Answer

Share private keys with trusted individuals.

Question 24

How does public-key cryptography fundamentally differ from symmetric cryptography?

Accepted Answer

Public-key cryptography uses separate keys for encryption and decryption, while symmetric cryptography uses the same key for both.

Answer

Public-key cryptography is less efficient than symmetric cryptography.

Answer

Public-key cryptography requires a trusted third party, while symmetric cryptography does not.

Question 25

What is the main purpose of a hash function within the context of public-key cryptography?

Accepted Answer

To generate a unique, fixed-length fingerprint (hash) from a variable-length input (message).

Answer

To verify the authenticity of a digital signature.

Answer

To encrypt messages without the need for keys.

Question 26

What is a significant limitation of public-key cryptography?

Accepted Answer

Certain operations, like key generation and encryption of large datasets, can be computationally expensive.

Answer

It requires a trusted central authority to manage keys.

Answer

It is inherently vulnerable to brute-force attacks.

Question 27

What is the primary advantage of using a blockchain wallet over a traditional cryptocurrency exchange?

Accepted Answer

Increased security and control over your private keys.

Answer

Ability to participate in blockchain governance.

Answer

Access to a wider range of cryptocurrencies.

Answer

Lower transaction fees.