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web.groovymark@gmail.com
- November 28, 2024
Question 01
Which cryptographic method is based on the difficulty of factoring large prime numbers?
a) AES
b) RSA
c) ECC
d) Blowfish
Correct Answer: b) RSA
Explanation: RSA encryption is based on the mathematical challenge of factoring large prime numbers, which makes it secure but computationally intensive.
Question 02
Which cipher uses a 5×5 matrix to encrypt and decrypt messages?
a) Playfair
b) Caesar
c) Vigenère
d) Rail Fence
Correct Answer: a) Playfair
Explanation: The Playfair cipher uses a 5x5 grid of letters for encryption and decryption, where plaintext letters are replaced based on their position in the matrix.
Question 03
What is a primary characteristic of a stream cipher?
a) It encrypts data in fixed-size blocks
b) It encrypts data one bit or byte at a time
c) It always requires padding
d) It can only be used for asymmetric encryption
Correct Answer: b) It encrypts data one bit or byte at a time
Explanation: Stream ciphers encrypt data one bit or byte at a time, making them faster and suitable for real-time data transmission.
Question 04
Which of the following block cipher modes is the most vulnerable to attacks due to the lack of initialization vectors?
a) ECB
b) CBC
c) OFB
d) CTR
Correct Answer: a) ECB
Explanation: ECB mode does not use initialization vectors, which means identical plaintext blocks will produce identical ciphertext blocks, making it vulnerable to pattern analysis.
Question 05
Which encryption method is used in WPA2 to secure Wi-Fi networks?
a) DES
b) AES
c) RSA
d) Blowfish
Correct Answer: b) AES
Explanation: AES encryption is used in WPA2 to secure Wi-Fi networks because it provides strong encryption and is resistant to known vulnerabilities.
Question 06
Which of the following describes a brute-force attack?
a) An attacker tries to guess the encryption key by testing all possible combinations
b) An attacker uses frequency analysis to deduce the encryption key
c) An attacker manipulates the encryption algorithm to bypass security
d) An attacker obtains the plaintext and ciphertext to reverse-engineer the key
Correct Answer: a) An attacker tries to guess the encryption key by testing all possible combinations
Explanation: In a brute-force attack, the attacker systematically tests every possible key combination until the correct key is found.
Question 07
Which cryptographic technique allows mathematical operations to be performed on encrypted data without decrypting it first?
a) Symmetric encryption
b) Homomorphic encryption
c) Elliptic Curve Cryptography
d) Hashing
Correct Answer: b) Homomorphic encryption
Explanation: Homomorphic encryption allows for computations to be performed on encrypted data, making it useful in scenarios where data privacy must be maintained during processing.
Question 08
Which of the following hash algorithms produces a 160-bit output?
a) MD5
b) SHA-1
c) SHA-256
d) AES
Correct Answer: b) SHA-1
Explanation: SHA-1 produces a 160-bit hash output, although it is now considered weak due to vulnerability to collision attacks.
Question 09
What is the primary advantage of Elliptic Curve Cryptography (ECC) over RSA?
a) It is easier to implement
b) It uses smaller keys for the same level of security
c) It is more secure than RSA
d) It does not require a public key infrastructure
Correct Answer: b) It uses smaller keys for the same level of security
Explanation: ECC offers the same security as RSA but with much smaller key sizes, making it more efficient in terms of computational overhead and storage requirements.
Question 10
Which cipher is known for shifting each letter in the plaintext by a fixed number of positions in the alphabet?
a) Playfair
b) Caesar
c) Vigenère
d) Rail Fence
Correct Answer: b) Caesar
Explanation: The Caesar cipher is a simple substitution cipher that shifts each letter by a fixed number of positions, typically by three.
Question 11
Which of the following is an example of a block cipher?
a) AES
b) RC4
c) ChaCha20
d) One-time pad
Correct Answer: a) AES
Explanation: AES is a block cipher, meaning it encrypts data in fixed-size blocks, as opposed to stream ciphers like RC4 that encrypt data one bit or byte at a time.
Question 12
Which of the following encryption modes is best suited for high-performance parallel processing of encrypted blocks?
a) ECB
b) CBC
c) CTR
d) CFB
Correct Answer: c) CTR
Explanation: CTR mode allows for parallel processing because each block is encrypted independently, improving performance in high-speed systems.
Question 13
Which of the following is a public key encryption algorithm?
a) AES
b) DES
c) RSA
d) RC5
Correct Answer: c) RSA
Explanation: RSA is a public key encryption algorithm, while AES, DES, and RC5 are symmetric key algorithms.
Question 14
Which of the following encryption techniques uses the same key for both encryption and decryption?
a) RSA
b) AES
c) ECC
d) Diffie-Hellman
Correct Answer: b) AES
Explanation: AES is a symmetric encryption algorithm, meaning the same key is used for both encryption and decryption.
Question 15
What is the main vulnerability of using ECB mode for block encryption?
a) It requires an initialization vector for each block
b) Identical plaintext blocks produce identical ciphertext blocks
c) It does not support parallel processing
d) It can only encrypt small amounts of data
Correct Answer: b) Identical plaintext blocks produce identical ciphertext blocks
Explanation: ECB mode is vulnerable because identical plaintext blocks always result in identical ciphertext blocks, making it susceptible to pattern analysis.
Question 16
What is the primary function of a Certificate Authority (CA) in public key infrastructure?
a) To issue and manage digital certificates
b) To store public and private keys
c) To generate symmetric encryption keys
d) To perform hashing operations
Correct Answer: a) To issue and manage digital certificates
Explanation: A Certificate Authority is responsible for issuing, validating, and managing digital certificates used to verify the identity of entities in a public key infrastructure.
Question 17
Which type of cryptographic attack involves capturing and reusing a valid transmission at a later time?
a) Replay attack
b) Man-in-the-middle attack
c) Chosen ciphertext attack
d) Brute-force attack
Correct Answer: a) Replay attack
Explanation: In a replay attack, an attacker captures a valid data transmission and replays it at a later time to gain unauthorized access.
Question 18
Which of the following describes the use of a one-time pad in encryption?
a) The same key is used for multiple messages
b) A different key is used for each message, and it is only used once
c) It involves a simple substitution cipher
d) It uses a fixed block size for encryption
Correct Answer: b) A different key is used for each message, and it is only used once
Explanation: A one-time pad uses a key that is randomly generated and used only once, making it theoretically unbreakable if the key is truly random and kept secret.
Question 19
Which type of encryption algorithm is based on the difficulty of solving discrete logarithms?
a) RSA
b) AES
c) ECC
d) Diffie-Hellman
Correct Answer: d) Diffie-Hellman
Explanation: Diffie-Hellman is a key exchange algorithm based on the difficulty of solving discrete logarithms, providing a way to securely exchange cryptographic keys over an insecure channel.
Question 20
Which hashing method produces a 256-bit output?
a) MD5
b) SHA-1
c) SHA-256
d) AES
Correct Answer: c) SHA-256
Explanation: SHA-256 is a cryptographic hash function that produces a 256-bit hash value, offering stronger security compared to MD5 and SHA-1.
