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- November 29, 2024
Question 41
What is the primary advantage of using a stream cipher over a block cipher?
a) It provides stronger encryption
b) It is faster and more efficient for real-time communications
c) It requires no key exchange
d) It uses smaller key sizes
Correct Answer: b) It is faster and more efficient for real-time communications
Explanation: Stream ciphers are generally faster and more efficient than block ciphers for encrypting real-time communications, such as voice or video streams.
Question 42
What is the primary function of a cryptographic hash function?
a) To encrypt data for secure transmission
b) To ensure data integrity by generating a fixed-length output
c) To generate a public and private key pair
d) To create a digital signature
Correct Answer: b) To ensure data integrity by generating a fixed-length output
Explanation: A cryptographic hash function ensures data integrity by generating a unique, fixed-length hash value from input data, allowing verification that the data has not been altered.
Question 43
Which cryptographic algorithm is based on the difficulty of solving discrete logarithms?
a) RSA
b) AES
c) ECC
d) DES
Correct Answer: c) ECC
Explanation: Elliptic Curve Cryptography (ECC) is based on the mathematical difficulty of solving discrete logarithms, making it secure for encryption and key exchange.
Question 44
Which type of cipher involves shifting the letters of the plaintext by a fixed number of positions?
a) Playfair cipher
b) Vigenère cipher
c) Caesar cipher
d) Rail Fence cipher
Correct Answer: c) Caesar cipher
Explanation: The Caesar cipher is a substitution cipher that shifts each letter of the plaintext by a fixed number of positions in the alphabet.
Question 45
What is the key length for AES-192 encryption?
a) 128 bits
b) 192 bits
c) 256 bits
d) 64 bits
Correct Answer: b) 192 bits
Explanation: AES-192 uses a 192-bit key for encryption, providing a higher level of security than AES-128.
Question 46
Which of the following best describes the purpose of digital signatures in cryptography?
a) To encrypt data for secure transmission
b) To verify the authenticity and integrity of a message
c) To hash data for verification
d) To exchange encryption keys securely
Correct Answer: b) To verify the authenticity and integrity of a message
Explanation: Digital signatures are used to verify the authenticity and integrity of a message, ensuring that it was sent by the claimed sender and has not been tampered with.
Question 47
Which of the following cryptographic algorithms is commonly used for generating a digital signature?
a) AES
b) RSA
c) DES
d) SHA-256
Correct Answer: b) RSA
Explanation: RSA is widely used for generating digital signatures, which provide authentication and data integrity by verifying the identity of the sender.
Question 48
What is the primary function of a Certificate Authority (CA) in public key infrastructure?
a) To generate encryption keys
b) To issue and manage digital certificates
c) To encrypt data for secure transmission
d) To store private keys securely
Correct Answer: b) To issue and manage digital certificates
Explanation: A Certificate Authority (CA) is responsible for issuing, managing, and validating digital certificates used in public key infrastructure (PKI).
Question 49
Which type of cryptographic attack involves analyzing the frequency of letters in a ciphertext to crack the encryption?
a) Brute-force attack
b) Replay attack
c) Frequency analysis attack
d) Man-in-the-middle attack
Correct Answer: c) Frequency analysis attack
Explanation: A frequency analysis attack involves analyzing the frequency of letters or symbols in ciphertext to deduce the underlying plaintext or encryption key.
Question 50
What is the primary purpose of a cryptographic nonce?
a) To store a secret key
b) To ensure that identical plaintexts produce different ciphertexts
c) To generate a digital signature
d) To provide authentication
Correct Answer: b) To ensure that identical plaintexts produce different ciphertexts
Explanation: A nonce is a random value used only once in encryption to ensure that the same plaintext encrypted multiple times results in different ciphertexts.
