Cryptography Fundamentals: Master the Basics of Information Security

Question 1

Which characteristic is NOT associated with a robust encryption algorithm?

Accepted Answer

Accessibility

Answer

Confidentiality

Answer

Integrity

Answer

Non-repudiation

Question 2

What is the primary purpose of a hash function?

Accepted Answer

Generating an irreversible and unique digest of data

Answer

Encrypting data

Answer

Creating a digital signature

Answer

Managing cryptographic keys

Question 3

What is the primary objective of key management in cryptography?

Accepted Answer

Generating and distributing cryptographic keys

Answer

Encrypting and decrypting data

Answer

Verifying digital signatures

Answer

Hashing data

Question 4

What is the function of a digital certificate?

Accepted Answer

Linking a public key to its owner's identity

Answer

Encrypting data

Answer

Signing digital messages

Answer

Generating cryptographic keys

Question 5

Which of the following encryption algorithms operates on a secret key shared between the sender and recipient?

Accepted Answer

AES

Answer

RSA

Answer

SHA-256

Answer

ECC

Question 6

What is the primary purpose of a hash function in cryptography?

Accepted Answer

To verify the integrity of data

Answer

To encrypt data

Answer

To generate digital signatures

Answer

To create secret keys

Question 7

Which advantage is attributed to public-key cryptography?

Accepted Answer

Enhanced security compared to symmetric-key cryptography

Answer

Simplified implementation compared to symmetric-key cryptography

Answer

Faster encryption process than symmetric-key cryptography

Answer

Elimination of the need for digital signatures

Question 8

What is the primary function of a digital signature in cryptography?

Accepted Answer

To authenticate messages

Answer

To encrypt data

Answer

To generate hash values

Answer

To create secret keys

Question 9

In password hashing, what is the purpose of incorporating a salt?

Accepted Answer

Enhancement of hash security

Answer

Improvement of hashing algorithm performance

Answer

Simplification of hash memorization

Answer

No specific purpose

Question 10

Which of the following is NOT a component of a symmetric encryption algorithm?

Accepted Answer

Public key

Answer

Encryption key

Answer

Decryption key

Answer

Initialization vector

Question 11

What is the primary purpose of a hash function in cryptography?

Accepted Answer

To create a unique fingerprint of data

Answer

To encrypt data

Answer

To digitally sign messages

Answer

To generate encryption keys

Question 12

Which of the following is a commonly used symmetric block cipher?

Accepted Answer

AES

Answer

RSA

Answer

SHA-256

Answer

ECC

Question 13

What is the main difference between a substitution cipher and a transposition cipher?

Accepted Answer

Substitution ciphers substitute characters, while transposition ciphers change the order of characters

Answer

Substitution ciphers change the order of characters, while transposition ciphers substitute characters

Answer

Substitution ciphers use keys, while transposition ciphers do not

Answer

Transposition ciphers use keys, while substitution ciphers do not

Question 14

What is the main purpose of a hash function in cryptography?

Accepted Answer

To generate a unique digital fingerprint of a message

Answer

To encrypt data

Answer

To generate encryption keys

Answer

To verify the authenticity of a digital signature

Question 15

What is the primary responsibility of key management in cryptography?

Accepted Answer

All of the above are primary responsibilities of key management in cryptography

Answer

Generating, managing, and securely storing encryption and decryption keys

Answer

Ensuring the secure distribution of keys

Answer

Protecting keys from unauthorized access

Question 16

Which of the following is a benefit of using symmetric-key encryption?

Accepted Answer

Both faster encryption and decryption and easier key management

Answer

Faster encryption and decryption

Answer

Easier key management

Answer

Neither faster encryption and decryption nor easier key management

Question 17

What is the key difference between a block cipher and a stream cipher?

Accepted Answer

Block ciphers encrypt data in fixed-size blocks, while stream ciphers encrypt data in a continuous stream

Answer

Stream ciphers are faster than block ciphers

Answer

Block ciphers are more secure than stream ciphers

Answer

There is no difference between block ciphers and stream ciphers

Question 18

What is the primary goal of cryptography?

Accepted Answer

All of the above are primary goals of cryptography

Answer

To protect the confidentiality, integrity, and availability of information

Answer

To ensure the authenticity of communication

Answer

To prevent unauthorized access to data

Question 19

Which of the following is a real-world application of cryptography?

Accepted Answer

All of the above are real-world applications of cryptography

Answer

Secure online banking transactions

Answer

Encrypting messages on social media platforms

Answer

Protecting sensitive data on mobile devices

Question 20

What is a potential drawback of using strong encryption?

Accepted Answer

Possible challenges for law enforcement investigations

Answer

Increased security for sensitive data

Answer

Decreased cyber threats

Question 21

Which protocol is used for key exchange?

Accepted Answer

Diffie-Hellman

Answer

SSL

Answer

RSA

Answer

AES

Question 22

Which of the following is NOT a fundamental concept of cryptography?

Accepted Answer

Data compression

Answer

Encryption algorithms

Answer

Hash functions

Answer

Digital signatures

Question 23

What is the primary purpose of an encryption algorithm?

Accepted Answer

To render plaintext unintelligible

Answer

To generate a digital signature for a message

Answer

To verify the authenticity of a message

Answer

To create a hash value for a file

Question 24

Which of the following is a symmetric encryption algorithm?

Accepted Answer

AES

Answer

RSA

Answer

DSA

Answer

ECC

Question 25

What is the purpose of a hash function in cryptography?

Accepted Answer

To generate a unique 'fingerprint' of data

Answer

To encrypt data securely

Answer

To create a digital signature

Answer

To generate a secret key

Question 26

What is the purpose of a public key infrastructure (PKI) in cryptography?

Accepted Answer

To manage and distribute digital certificates

Answer

To generate and manage cryptographic keys

Answer

To provide secure communication channels

Answer

To store encrypted data

Question 27

What is post-quantum cryptography and why is it crucial for protecting data in the face of future threats?

Accepted Answer

Post-quantum cryptography refers to algorithms designed to withstand attacks from quantum computers.

Answer

Post-quantum cryptography is only used to encrypt data on physical devices.

Answer

Post-quantum cryptography and quantum cryptography are the same thing.

Answer

Post-quantum cryptography is purely theoretical and has no practical use.

Question 28

How do cryptographic hash functions contribute to data integrity and what is their role in digital signatures and message authentication codes?

Accepted Answer

Hash functions generate a unique and irreversible representation of data, allowing detection of any unauthorized alterations, ensuring data integrity.

Answer

Hashing functions encrypt data using a key, making it inaccessible to unauthorized parties.

Answer

Hashing functions generate random values that can enhance the security of encryption algorithms.

Answer

Hashing functions are used solely for signing digital documents, ensuring their authenticity.

Question 29

Which of the following is an invalid key management practice?

Accepted Answer

Key Forging

Answer

Key Generation

Answer

Key Distribution

Answer

Key Revocation

Question 30

Identify the key difference between substitution and transposition ciphers. Provide specific examples to illustrate your answer.

Accepted Answer

Substitution ciphers replace characters with different ones (e.g., 'A' becomes 'Z'), while transposition ciphers rearrange the order of characters (e.g., 'ABC' becomes 'BCA').

Answer

Substitution ciphers use a fixed key, while transposition ciphers use a variable key.

Answer

Substitution ciphers are more secure than transposition ciphers.

Answer

Transposition ciphers operate on the bit-level, while substitution ciphers operate on the byte-level.

Question 31

In the Diffie-Hellman key exchange protocol, how do parties establish a shared secret key over insecure channels, and why is this significant?

Accepted Answer

By exchanging exponentials of a shared base, leveraging the difficulty of solving the discrete logarithm problem to protect the key from eavesdropping.

Answer

By directly exchanging encrypted messages, relying on the difficulty of factoring large numbers into primes for security.

Answer

By using a single key for both encryption and decryption, making it a symmetric-key exchange protocol.

Answer

By generating and verifying digital signatures, ensuring the authenticity of digital documents.

Question 32

Explain how key size affects the difficulty of brute-force attacks on encryption algorithms. Give an example to demonstrate this relationship.

Accepted Answer

The difficulty of a brute-force attack increases exponentially as the key size increases.

Answer

The difficulty of a brute-force attack is directly proportional to the key size.

Answer

The difficulty of a brute-force attack is unaffected by the key size.

Answer

The difficulty of a brute-force attack decreases as the key size increases.

Question 33

Which algorithm uses the same key for both encryption and decryption?

Accepted Answer

AES

Answer

RSA

Answer

SHA-256

Question 34

In block cipher modes of operation, what is the primary cryptographic purpose of a random initialization vector (IV)?

Accepted Answer

To ensure that identical plaintext blocks always encrypt to different ciphertext blocks, increasing the unpredictability and security of the encryption process.

Answer

To act as the encryption key for the first block of plaintext.

Answer

To be used exclusively in certain block cipher modes of operation, such as Cipher Block Chaining (CBC) mode.

Answer

To have no significant cryptographic importance.

Question 35

Which property is NOT characteristic of a secure hash function?

Accepted Answer

Invertible property

Answer

One-way property

Answer

Collision resistance

Question 36

Which of the following ciphers operates on individual bits of data?

Accepted Answer

Stream cipher

Answer

Public key cipher

Answer

Symmetric key cipher

Answer

Block cipher

Question 37

What is the primary function of a digital signature?

Accepted Answer

To provide authentication and integrity of a message

Answer

To generate a hash of a message

Answer

To encrypt a message

Question 38

Which key management technique involves dividing a secret key into multiple parts and distributing them to different locations?

Accepted Answer

Secret sharing

Answer

Key escrow

Answer

Certificate authority

Answer

Key revocation

Question 39

What is a major advantage of using a public key cryptosystem?

Accepted Answer

It allows for secure key exchange over an insecure channel.

Answer

It is faster than a symmetric key cryptosystem.

Answer

It provides stronger encryption than a symmetric key cryptosystem.

Question 40

Which of the following algorithms is commonly used for symmetric key encryption?

Accepted Answer

AES

Answer

ECC

Answer

SHA-256

Answer

RSA

Question 41

What is the key difference between a nonce and a salt?

Accepted Answer

A nonce is used only once per encryption operation, while a salt is used to make password hashing more secure.

Answer

A salt is used only once per encryption operation, while a nonce is used to make password hashing more secure.

Question 42

Which of the following is a significant weakness of the CBC (Cipher Block Chaining) mode of operation?

Accepted Answer

It is vulnerable to padding oracle attacks.

Answer

It does not provide message integrity protection.

Answer

It is slow and computationally expensive.

Question 43

What is the primary purpose of using a cryptographic random number generator (CSPRNG)?

Accepted Answer

To generate unpredictable and truly random numbers for cryptographic applications.

Answer

To generate hashes of messages

Answer

To encrypt sensitive data

Question 44

Which of the following is NOT a benefit of using cryptography in information security?

Accepted Answer

It prevents all data breaches.

Answer

It provides data integrity.

Answer

It enables secure communication.

Answer

It ensures data confidentiality.