Multiple-choice questions (MCQs) on Network Cryptography

1. What is the primary purpose of network cryptography?

a) To improve network speed
b) To ensure data confidentiality, integrity, and authenticity
c) To store data securely
d) To reduce bandwidth consumption

Answer: b) To ensure data confidentiality, integrity, and authenticity


2. Which of the following is a type of symmetric encryption?

a) RSA
b) AES
c) ECC
d) DSA

Answer: b) AES


3. In asymmetric cryptography, which key is used for encryption?

a) Private key
b) Public key
c) Session key
d) Master key

Answer: b) Public key


4. Which of the following is used to ensure the integrity of a message?

a) Encryption
b) Hashing
c) Digital signature
d) Symmetric encryption

Answer: b) Hashing


5. Which protocol is commonly used to secure communication over the internet?

a) HTTP
b) FTP
c) SSL/TLS
d) SMTP

Answer: c) SSL/TLS


6. What is the main disadvantage of symmetric encryption?

a) Slow encryption speed
b) Difficulty in key distribution
c) Inability to be used for authentication
d) It is computationally expensive

Answer: b) Difficulty in key distribution


7. Which encryption algorithm is widely used for secure email communication?

a) AES
b) RSA
c) DES
d) Blowfish

Answer: b) RSA


8. What is the output of a hashing algorithm?

a) Plaintext
b) Ciphertext
c) Fixed-length value (hash value)
d) Public key

Answer: c) Fixed-length value (hash value)


9. Which of the following is used for secure key exchange in asymmetric encryption?

a) AES
b) RSA
c) Diffie-Hellman
d) DES

Answer: c) Diffie-Hellman


10. What is the primary function of a Digital Signature?

a) To encrypt the message
b) To verify the sender’s authenticity
c) To ensure the data’s confidentiality
d) To provide public key infrastructure

Answer: b) To verify the sender’s authenticity


11. Which of the following is a popular hashing algorithm?

a) SHA
b) DES
c) RSA
d) AES

Answer: a) SHA


12. What does SSL stand for?

a) Secure Socket Layer
b) Secure Service Layer
c) Software Security Layer
d) Secure System Layer

Answer: a) Secure Socket Layer


13. What is a key feature of elliptic curve cryptography (ECC)?

a) It uses very long keys
b) It is computationally expensive
c) It provides the same security with shorter keys compared to RSA
d) It uses a symmetric encryption algorithm

Answer: c) It provides the same security with shorter keys compared to RSA


14. Which of the following is a property of a good cryptographic hash function?

a) It should produce a variable-length output
b) It should be a reversible function
c) It should produce a unique output for every input
d) It should produce a fixed-length output

Answer: d) It should produce a fixed-length output


15. What is the role of a certificate authority (CA) in SSL/TLS?

a) To verify the integrity of the message
b) To issue and verify digital certificates
c) To encrypt data
d) To distribute encryption keys

Answer: b) To issue and verify digital certificates


16. What type of encryption is used in WPA2 for wireless security?

a) AES
b) DES
c) RSA
d) Triple DES

Answer: a) AES


17. Which algorithm is typically used for hashing passwords?

a) RSA
b) AES
c) SHA-256
d) Diffie-Hellman

Answer: c) SHA-256


18. Which of the following cryptographic algorithms is asymmetric?

a) DES
b) AES
c) RSA
d) Blowfish

Answer: c) RSA


19. What is the main advantage of asymmetric encryption?

a) Faster processing
b) Better key management
c) No need for key exchange
d) Higher security with smaller keys

Answer: b) Better key management


20. Which of the following provides authentication and confidentiality in communication?

a) Symmetric encryption
b) Asymmetric encryption
c) Digital signatures
d) Hashing

Answer: b) Asymmetric encryption


21. What does the RSA algorithm rely on for security?

a) Elliptic curve math
b) Modular arithmetic and large prime numbers
c) Block ciphers
d) Random number generation

Answer: b) Modular arithmetic and large prime numbers


22. What is the purpose of a session key in cryptography?

a) To sign the messages
b) To encrypt data for a single session
c) To encrypt the private key
d) To authenticate users

Answer: b) To encrypt data for a single session


23. Which encryption method uses the same key for both encryption and decryption?

a) Asymmetric encryption
b) Symmetric encryption
c) Hashing
d) Digital signature

Answer: b) Symmetric encryption


24. What does “confidentiality” in cryptography refer to?

a) Ensuring the data is not modified
b) Ensuring only authorized parties can read the data
c) Verifying the sender’s identity
d) Ensuring that the data is encrypted

Answer: b) Ensuring only authorized parties can read the data


25. Which cryptographic technique is used to verify the integrity of data?

a) Encryption
b) Digital signature
c) Hashing
d) Symmetric key exchange

Answer: c) Hashing


26. Which of the following is true about symmetric encryption?

a) It requires a pair of keys: public and private
b) It is more efficient than asymmetric encryption
c) It is slower than asymmetric encryption
d) It requires a certificate authority

Answer: b) It is more efficient than asymmetric encryption


27. Which of the following is a disadvantage of using symmetric encryption?

a) It is slow
b) Key distribution is a problem
c) It requires two keys
d) It is computationally expensive

Answer: b) Key distribution is a problem


28. Which of the following best describes the function of a public key in asymmetric encryption?

a) It is used to decrypt the data
b) It is kept private and known only to the user
c) It is used to encrypt the data
d) It is used to sign the data

Answer: c) It is used to encrypt the data


29. What does the term “brute-force attack” refer to in cryptography?

a) Intercepting encrypted data
b) Trying all possible keys to decrypt data
c) Breaking the encryption algorithm
d) Stealing encryption keys from a user

Answer: b) Trying all possible keys to decrypt data


30. Which of the following is an example of a cryptographic key exchange protocol?

a) RSA
b) SHA-256
c) Diffie-Hellman
d) AES

Answer: c) Diffie-Hellman


31. What is a potential risk of weak encryption algorithms?

a) Slower performance
b) Easier to decrypt the data by attackers
c) Higher costs
d) Complexity in implementation

Answer: b) Easier to decrypt the data by attackers


32. Which encryption algorithm is considered to be quantum-safe?

a) AES
b) RSA
c) ECC
d) Lattice-based cryptography

Answer: d) Lattice-based cryptography


33. In which layer of the OSI model does SSL/TLS operate?

a) Network Layer
b) Transport Layer
c) Application Layer
d) Data Link Layer

Answer: b) Transport Layer


34. What is the main purpose of a Digital Certificate?

a) To encrypt data
b) To verify the authenticity of the public key
c) To generate encryption keys
d) To hash data

Answer: b) To verify the authenticity of the public key


35. Which of the following is a characteristic of a good encryption key?

a) Short length
b) Easily guessable
c) Random and unpredictable
d) Static and unchanging

Answer: c) Random and unpredictable


36. What is the function of a nonce in cryptographic protocols?

a) To create a hash value
b) To ensure unique encryption for each session
c) To generate private keys
d) To validate digital signatures

Answer: b) To ensure unique encryption for each session


37. Which of the following is used for data integrity verification in SSL/TLS?

a) Hash functions
b) Public key
c) Session key
d) Diffie-Hellman

Answer: a) Hash functions


38. Which of the following is true about encryption key length?

a) A longer key length generally offers better security
b) A longer key length reduces encryption speed
c) A longer key length is always better
d) Both a) and b) are correct

Answer: d) Both a) and b) are correct


39. In which scenario is symmetric encryption most commonly used?

a) Secure email communication
b) Secure file storage
c) Digital signatures
d) Secure key exchange

Answer: b) Secure file storage


40. What is the purpose of the TLS handshake?

a) To verify the integrity of the data
b) To establish a secure connection between client and server
c) To authenticate the sender’s identity
d) To encrypt the data

Answer: b) To establish a secure connection between client and server


41. Which of the following is a hashing algorithm used in digital certificates?

a) SHA-256
b) DES
c) AES
d) RSA

Answer: a) SHA-256


42. What is the primary function of a cryptographic algorithm?

a) To generate keys
b) To prevent unauthorized access to data
c) To sign messages
d) To exchange keys securely

Answer: b) To prevent unauthorized access to data


43. What is the primary benefit of using Elliptic Curve Cryptography (ECC)?

a) It requires longer keys than RSA
b) It is computationally more efficient with shorter keys
c) It is easier to implement
d) It is more secure than AES

Answer: b) It is computationally more efficient with shorter keys


44. In which type of cryptography does the same key encrypt and decrypt the data?

a) Asymmetric
b) Symmetric
c) Hybrid
d) Quantum

Answer: b) Symmetric


45. What is the main security feature provided by HTTPS?

a) Data compression
b) Data integrity and confidentiality
c) Session management
d) Speed optimization

Answer: b) Data integrity and confidentiality


46. What is the term for the process of transforming plaintext into ciphertext?

a) Decryption
b) Hashing
c) Encryption
d) Key generation

Answer: c) Encryption


47. Which of the following is true about Digital Signatures?

a) They ensure confidentiality
b) They authenticate the identity of the sender
c) They are created using symmetric encryption
d) They are used to generate encryption keys

Answer: b) They authenticate the identity of the sender


48. In which cryptographic algorithm is the RSA public key used for encryption?

a) AES
b) RSA
c) Diffie-Hellman
d) ElGamal

Answer: b) RSA


49. What does the term “PKI” stand for in network cryptography?

a) Public Key Infrastructure
b) Private Key Interface
c) Protected Key Interchange
d) Public Key Interface

Answer: a) Public Key Infrastructure


50. Which of the following algorithms is primarily used for encrypting web traffic?

a) AES
b) RSA
c) SSL/TLS
d) SHA-256

Answer: c) SSL/TLS

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