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web.groovymark@gmail.com
- November 29, 2024
Question 21
What is the main purpose of a Certificate Authority (CA) in cryptography?
a) To generate private keys for encryption
b) To issue and manage digital certificates
c) To hash data for verification
d) To store public 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, which are used to verify the identity of parties in secure communications.
Question 22
Which of the following is the most secure symmetric encryption algorithm?
a) DES
b) RSA
c) AES
d) Blowfish
Correct Answer: c) AES
Explanation: AES is considered the most secure symmetric encryption algorithm, offering strong encryption with key sizes of 128, 192, and 256 bits.
Question 23
Which type of cryptographic attack involves capturing and reusing valid data transmissions?
a) Man-in-the-middle attack
b) Replay attack
c) Brute-force attack
d) Timing attack
Correct Answer: b) Replay attack
Explanation: In a replay attack, the attacker captures valid data transmissions and reuses them at a later time to gain unauthorized access.
Question 24
Which cryptographic algorithm is used for generating a hash value?
a) AES
b) RSA
c) SHA-256
d) Diffie-Hellman
Correct Answer: c) SHA-256
Explanation: SHA-256 is a cryptographic hash algorithm that generates a fixed-length hash value, ensuring data integrity.
Question 25
Which of the following describes a digital signature?
a) It encrypts a message for secure transmission
b) It verifies the identity of the sender and the integrity of the message
c) It generates a public and private key pair
d) It encrypts data using symmetric encryption
Correct Answer: b) It verifies the identity of the sender and the integrity of the message
Explanation: A digital signature verifies the identity of the sender and ensures that the message has not been tampered with during transmission.
Question 26
Which of the following cryptographic methods uses different keys for encryption and decryption?
a) Symmetric encryption
b) Asymmetric encryption
c) Hashing
d) Stream ciphers
Correct Answer: b) Asymmetric encryption
Explanation: Asymmetric encryption uses different keys for encryption and decryption, typically a public key for encryption and a private key for decryption.
Question 27
Which of the following is a symmetric block cipher?
a) RSA
b) ECC
c) AES
d) Diffie-Hellman
Correct Answer: c) AES
Explanation: AES is a symmetric block cipher that encrypts data in fixed-size blocks using the same key for both encryption and decryption.
Question 28
Which type of cryptographic attack exploits weaknesses in the physical implementation of encryption, such as timing or power consumption?
a) Replay attack
b) Side-channel attack
c) Brute-force attack
d) Man-in-the-middle attack
Correct Answer: b) Side-channel attack
Explanation: A side-channel attack exploits weaknesses in the physical implementation of encryption, such as timing, power consumption, or electromagnetic leaks, to deduce the encryption key or other sensitive information.
Question 29
What is the block size of the AES encryption algorithm?
a) 64 bits
b) 128 bits
c) 192 bits
d) 256 bits
Correct Answer: b) 128 bits
Explanation: AES has a fixed block size of 128 bits, regardless of the key length used in the encryption process.
Question 30
Which of the following describes a brute-force attack?
a) The attacker decrypts a message by trying all possible keys
b) The attacker intercepts and modifies data in transit
c) The attacker analyzes the frequency of letters in ciphertext to break the encryption
d) The attacker selects ciphertext to decrypt and analyzes the plaintext
Correct Answer: a) The attacker decrypts a message by trying all possible keys
Explanation: A brute-force attack involves trying all possible keys until the correct key is found to decrypt the ciphertext.
Question 31
What is the key length for AES-256 encryption?
a) 128 bits
b) 192 bits
c) 256 bits
d) 64 bits
Correct Answer: c) 256 bits
Explanation: AES-256 uses a 256-bit key for encryption, providing a higher level of security than AES-128 or AES-192.
Question 32
Which of the following best describes the function of hashing in cryptography?
a) It encrypts data for secure transmission
b) It ensures data integrity by producing a fixed-length output from a variable-length input
c) It generates a secret key for encryption
d) It is used to decrypt ciphertext
Correct Answer: b) It ensures data integrity by producing a fixed-length output from a variable-length input
Explanation: Hashing ensures data integrity by producing a unique, fixed-length hash value from a variable-length input, allowing verification that the data has not been altered.
Question 33
Which of the following block cipher modes of operation is vulnerable to pattern analysis because identical plaintext blocks produce identical ciphertext blocks?
a) ECB
b) CBC
c) CFB
d) OFB
Correct Answer: a) ECB
Explanation: In Electronic Codebook (ECB) mode, identical plaintext blocks produce identical ciphertext blocks, making it vulnerable to pattern analysis attacks.
Question 34
Which of the following best describes forward secrecy?
a) It prevents the sender from denying that they sent a message
b) It ensures that a session key is not reused in future sessions
c) It allows a message to be encrypted using the recipient’s public key
d) It ensures that the same key is used for encryption and decryption
Correct Answer: b) It ensures that a session key is not reused in future sessions
Explanation: Forward secrecy ensures that session keys are not reused in future sessions, providing additional security by preventing compromise of past communications.
Question 35
Which of the following cryptographic algorithms is based on the difficulty of factorizing large prime numbers?
a) AES
b) RSA
c) SHA-256
d) DES
Correct Answer: b) RSA
Explanation: RSA is based on the mathematical difficulty of factorizing large prime numbers, which forms the basis of its security
Question 36
What is the primary advantage of using a symmetric encryption algorithm like AES?
a) It allows for faster encryption and decryption
b) It provides stronger encryption than asymmetric algorithms
c) It requires no key exchange
d) It is easier to implement than asymmetric encryption
Correct Answer: a) It allows for faster encryption and decryption
Explanation: Symmetric encryption algorithms like AES are generally faster than asymmetric algorithms because they use the same key for both encryption and decryption.
Question 37
What is the primary disadvantage of symmetric encryption?
a) It is too slow for real-time applications
b) It requires a large key size
c) It requires secure key distribution
d) It is less secure than asymmetric encryption
Correct Answer: c) It requires secure key distribution
Explanation: The main disadvantage of symmetric encryption is the need for secure key distribution between parties, as both must use the same key.
Question 38
Which of the following describes the primary weakness of DES?
a) It uses a small key size
b) It is difficult to implement
c) It is a public-key encryption algorithm
d) It cannot be used in block cipher mode
Correct Answer: a) It uses a small key size
Explanation: DES has a small key size of 56 bits, which makes it vulnerable to brute-force attacks.
Question 39
Which cryptographic algorithm is commonly used for securing web traffic via HTTPS?
a) RSA
b) AES
c) DES
d) ECC
Correct Answer: a) RSA
Explanation: RSA is commonly used in HTTPS for securing web traffic, as it provides strong encryption for key exchanges and digital signatures.
Question 40
Which type of cryptographic attack attempts to decrypt ciphertext by trying all possible keys?
a) Known plaintext attack
b) Brute-force attack
c) Replay attack
d) Man-in-the-middle attack
Correct Answer: b) Brute-force attack
Explanation: In a brute-force attack, the attacker tries every possible key until the correct one is found to decrypt the ciphertext.
