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web.groovymark@gmail.com
- November 29, 2024
Question 21
Which type of cipher involves shifting the letters of the plaintext by a fixed number of positions?
a) Playfair cipher
b) Caesar cipher
c) Vigenère cipher
d) Transposition cipher
Correct Answer: b) Caesar cipher
Explanation: The Caesar cipher is a simple substitution cipher that shifts the letters of the plaintext by a fixed number of positions.
Question 22
Which block cipher mode of operation involves XORing each plaintext block with the previous ciphertext block?
a) ECB
b) CBC
c) CTR
d) CFB
Correct Answer: b) CBC
Explanation: Cipher Block Chaining (CBC) mode XORs each plaintext block with the previous ciphertext block before encryption, ensuring that identical plaintext blocks produce different ciphertexts.
Question 23
Which of the following encryption algorithms 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 24
Which of the following best describes a hash function?
a) It is reversible
b) It generates a fixed-length output from variable-length input
c) It uses a private key for decryption
d) It requires padding for encryption
Correct Answer: b) It generates a fixed-length output from variable-length input
Explanation: A hash function generates a fixed-length output (hash) from a variable-length input, ensuring data integrity without being reversible.
Question 25
Which of the following algorithms is commonly used for creating a digital signature?
a) AES
b) RSA
c) Blowfish
d) RC4
Correct Answer: b) RSA
Explanation: RSA is widely used for creating digital signatures, ensuring message integrity and authenticity.
Question 26
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 27
Which cryptographic attack involves manipulating the encryption algorithm to find weaknesses?
a) Brute-force attack
b) Man-in-the-middle attack
c) Cryptanalysis attack
d) Chosen-ciphertext attack
Correct Answer: c) Cryptanalysis attack
Explanation: A cryptanalysis attack involves manipulating the encryption algorithm to find weaknesses or patterns that can be exploited to break the encryption.
Question 28
Which of the following encryption modes allows for parallel processing of encrypted blocks?
a) ECB
b) CBC
c) CFB
d) CTR
Correct Answer: d) CTR
Explanation: Counter (CTR) mode allows for parallel processing because each block is encrypted independently, improving performance in high-speed environments.
Question 29
What is the primary purpose of forward secrecy?
a) To prevent man-in-the-middle attacks
b) To secure key exchanges
c) To ensure that past sessions remain secure even if long-term keys are compromised
d) To provide faster encryption and decryption
Correct Answer: c) To ensure that past sessions remain secure even if long-term keys are compromised
Explanation: Forward secrecy ensures that even if long-term keys are compromised, past communication sessions remain secure because session keys are not reused.
Question 30
Which type of encryption algorithm uses the same key for both encryption and decryption?
a) Asymmetric encryption
b) Symmetric encryption
c) Hashing
d) Digital signature
Correct Answer: b) Symmetric encryption
Explanation: In symmetric encryption, the same key is used for both encryption and decryption, requiring secure key exchange between the parties.
Question 31
Which of the following protocols is used to check the validity of digital certificates in real-time?
a) CRL
b) OCSP
c) RSA
d) Diffie-Hellman
Correct Answer: b) OCSP
Explanation: The Online Certificate Status Protocol (OCSP) is used to check the validity of digital certificates in real-time, ensuring that they have not been revoked.
Question 32
Which of the following best describes the function of a digital signature?
a) To ensure data confidentiality
b) To verify the identity of the sender and the integrity of the message
c) To encrypt messages for secure transmission
d) To generate cryptographic keys
Correct Answer: b) To verify 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 33
Which encryption algorithm is typically used in blockchain technologies for securing transactions?
a) AES
b) RSA
c) ECC
d) DES
Correct Answer: c) ECC
Explanation: Elliptic Curve Cryptography (ECC) is commonly used in blockchain technologies for securing transactions due to its efficiency and smaller key sizes.
Question 34
Which type of cryptographic attack involves capturing and reusing valid data transmissions?
a) Man-in-the-middle attack
b) Brute-force attack
c) Replay attack
d) Chosen-plaintext attack
Correct Answer: c) Replay attack
Explanation: In a replay attack, an attacker captures valid data transmissions and reuses them at a later time to gain unauthorized access
Question 35
Which cryptographic algorithm is used for generating a hash value?
a) AES
b) SHA-256
c) RSA
d) Diffie-Hellman
Correct Answer: b) SHA-256
Explanation: SHA-256 is a cryptographic hash algorithm that generates a fixed-length hash value, ensuring data integrity.
Question 36
Which of the following describes a man-in-the-middle attack?
a) An attacker intercepts and alters communications between two parties
b) An attacker uses brute-force techniques to decrypt encrypted data
c) An attacker impersonates one party in a communication to deceive the other
d) An attacker generates random keys to encrypt intercepted data
Correct Answer: a) An attacker intercepts and alters communications between two parties
Explanation: In a man-in-the-middle attack, an attacker intercepts and potentially alters the communication between two parties without their knowledge.
Question 37
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 38
What is the purpose of a nonce in encryption?
a) To provide a unique value used only once to ensure data uniqueness
b) To generate the encryption key
c) To pad the plaintext to a fixed length
d) To ensure that data remains confidential
Correct Answer: a) To provide a unique value used only once to ensure data uniqueness
Explanation: A nonce is a value used only once in encryption to ensure that the same plaintext encrypted multiple times results in different ciphertexts.
Question 39
Which of the following is a primary advantage of elliptic curve cryptography (ECC)?
a) It uses smaller key sizes for the same level of security as RSA
b) It is easier to implement than RSA
c) It requires less computational power
d) It is faster than symmetric encryption algorithms
Correct Answer: a) It uses smaller key sizes for the same level of security as RSA
Explanation: ECC provides equivalent security to RSA but with much smaller key sizes, making it more efficient in terms of computation and storage.
Question 40
Which encryption mode produces identical ciphertext for identical plaintext blocks, making it vulnerable to pattern analysis?
a) CBC
b) CTR
c) ECB
d) OFB
Correct Answer: c) ECB
Explanation: In ECB mode, identical plaintext blocks produce identical ciphertext blocks, making it vulnerable to pattern analysis attacks.
