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web.groovymark@gmail.com
- November 28, 2024
Question 01
Which of the following is an advantage of using a one-time pad in cryptography?
a) It is easy to implement
b) It can be reused multiple times
c) It is considered unbreakable
d) It is compatible with hardware encryption
Correct Answer: c) It is considered unbreakable
Explanation: A one-time pad is considered unbreakable because it uses a random key that is as long as the message and is used only once. This ensures that there is no repeating pattern that can be exploited by attackers.
Question 02
What is the primary purpose of a hardware security module (HSM)?
a) To manage cryptographic keys
b) To encrypt full disk volumes
c) To generate random numbers
d) To store digital certificates
Correct Answer: a) To manage cryptographic keys
Explanation: An HSM is a tamper-resistant device designed to manage, store, and protect cryptographic keys and perform cryptographic operations.
Question 03
Which encryption mode ensures that no two blocks of plaintext will ever produce the same ciphertext?
a) Electronic Code Book (ECB)
b) Cipher Block Chaining (CBC)
c) Counter Mode (CTR)
d) Output Feedback (OFB)
Correct Answer: b) Cipher Block Chaining (CBC)
Explanation: CBC mode XORs each plaintext block with the previous ciphertext block before encryption, ensuring that no two identical plaintext blocks produce the same ciphertext.
Question 04
Which type of cryptographic attack involves analyzing the frequency of letters or groups of letters?
a) Brute-force attack
b) Dictionary attack
c) Frequency analysis
d) Known plaintext attack
Correct Answer: c) Frequency analysis
Explanation: Frequency analysis involves studying the frequency of letters or groups of letters in a ciphertext to break the encryption. It is particularly effective against simple substitution ciphers.
Question 05
What is the key weakness of the Electronic Code Book (ECB) encryption mode?
a) It is too complex to implement
b) It requires initialization vectors
c) It encrypts identical plaintext blocks into identical ciphertext blocks
d) It does not support block encryption
Correct Answer: c) It encrypts identical plaintext blocks into identical ciphertext blocks
Explanation: ECB mode is insecure because it produces the same ciphertext for identical plaintext blocks, making it vulnerable to pattern analysis.
Question 06
Which of the following algorithms is commonly used in light-weight cryptography?
a) RSA
b) DES
c) SPECK
d) AES
Correct Answer: c) SPECK
Explanation: SPECK is a light-weight block cipher designed by the NSA, optimized for performance in hardware implementations, making it suitable for constrained environments like IoT devices.
Question 07
Which of the following hashing methods produces a 160-bit output?
a) MD5
b) SHA-1
c) SHA-256
d) SHA-512
Correct Answer: b) SHA-1
Explanation: SHA-1 produces a 160-bit hash value, though it is now considered insecure and has been largely replaced by stronger algorithms like SHA-256 and SHA-512.
Question 08
Which encryption technique is based on the mathematical difficulty of factoring large prime numbers?
a) AES
b) ECC
c) RSA
d) Diffie-Hellman
Correct Answer: c) RSA
Explanation: RSA relies on the difficulty of factoring large prime numbers, which makes it secure for encryption and digital signatures, though it is computationally intensive.
Question 09
What is the primary function of a digital certificate?
a) To generate random numbers
b) To provide a public key to verify signatures
c) To store cryptographic keys
d) To generate symmetric encryption keys
Correct Answer: b) To provide a public key to verify signatures
Explanation: A digital certificate binds a public key to an entity, allowing others to verify that entity’s signature or to encrypt messages using the public key
Question 10
In the Diffie-Hellman key exchange algorithm, what is exchanged between two parties?
a) Symmetric encryption keys
b) Private keys
c) Public keys
d) Digital certificates
Correct Answer: c) Public keys
Explanation: In the Diffie-Hellman key exchange, the two parties exchange public keys, which are used along with their own private keys to derive a shared secret key.
Question 11
Which of the following cryptographic operations can be performed without decrypting the data first?
a) Brute-force attack
b) Replay attack
c) Homomorphic encryption
d) Known-plaintext attack
Correct Answer: c) Homomorphic encryption
Explanation: Homomorphic encryption allows mathematical operations to be performed on encrypted data without needing to decrypt it, ensuring data privacy during processing
Question 12
Which of the following modes converts a block cipher into a synchronous stream cipher?
a) Cipher Block Chaining (CBC)
b) Counter Mode (CTR)
c) Output Feedback (OFB)
d) Electronic Code Book (ECB
Correct Answer: c) Output Feedback (OFB)
Explanation: OFB mode transforms a block cipher into a stream cipher by generating keystream blocks that are XORed with the plaintext, allowing block-by-block encryption.
Question 13
Which cryptographic hash function is widely considered vulnerable to collision attacks?
a) SHA-1
b) SHA-256
c) SHA-512
d) AES
Correct Answer: a) SHA-1
Explanation: SHA-1 has been proven vulnerable to collision attacks, where two different inputs produce the same hash value, compromising the integrity of the hash.
Question 14
What is a primary benefit of using elliptic curve cryptography (ECC) over RSA?
a) It uses smaller keys for the same level of security
b) It is easier to implement
c) It provides more secure hash functions
d) It does not require public key infrastructure
Correct Answer: a) It uses smaller keys for the same level of security
Explanation: ECC offers the same level of security as RSA but with much smaller key sizes, making it faster and more efficient, especially in resource-constrained environments.
Question 15
Which of the following describes a man-in-the-middle (MITM) attack?
a) The attacker gains access to both parties’ private keys
b) The attacker sends encrypted messages to both parties
c) The attacker intercepts and alters communication between two parties
d) The attacker floods a network with traffic to cause denial of service
Correct Answer: c) The attacker intercepts and alters communication between two parties
Explanation: A MITM attack involves the attacker secretly intercepting and potentially altering communication between two parties, without them knowing.
Question 16
Which encryption method is most commonly used to encrypt individual files in modern operating systems?
a) AES
b) RSA
c) SHA-1
d) Blowfish
Correct Answer: a) AES
Explanation: AES is widely used in modern operating systems like Windows and macOS to encrypt individual files and entire disk volumes due to its strength and efficiency.
Question 17
In public key cryptography, which key is used to decrypt a message that has been encrypted with the recipient’s public key?
a) The sender’s private key
b) The sender’s public key
c) The recipient’s private key
d) The recipient’s public key
Correct Answer: c) The recipient's private key
Explanation: In asymmetric encryption, a message encrypted with the recipient’s public key can only be decrypted by the recipient’s private key, ensuring confidentiality.
Question 18
What is the function of a nonce in cryptographic operations?
a) To provide padding for encrypted blocks
b) To prevent replay attacks
c) To encrypt data using a secret key
d) To generate a public/private key pair
Correct Answer: b) To prevent replay attacks
Explanation: A nonce is a number used once to ensure that old communications cannot be replayed by attackers, adding randomness to cryptographic protocols.
Question 19
Which of the following algorithms supports homomorphic encryption?
a) RSA
b) AES
c) Diffie-Hellman
d) Blowfish
Correct Answer: a) RSA
Explanation: RSA supports certain types of homomorphic encryption, allowing mathematical operations to be performed on ciphertext without decrypting it first.
Question 20
What is the block size used by AES?
a) 64 bits
b) 128 bits
c) 192 bits
d) 256 bits
Correct Answer: b) 128 bits
Explanation: AES uses a fixed block size of 128 bits, regardless of the key size, which can be 128, 192, or 256 bits.
