1. What is the underlying principle behind the Advanced Encryption Standard (AES)?
a) Public key encryption
b) Symmetric key encryption
c) Elliptic curve cryptography
d) Quantum cryptography
Answer: b) Symmetric key encryption
Explanation: AES is a symmetric key encryption algorithm, meaning the same key is used for both encryption and decryption.
2. Which of the following is a characteristic of public key cryptography?
a) Both parties share the same secret key
b) Only one key is used for encryption and decryption
c) Each party has a pair of keys: public and private
d) It relies on the discrete logarithm problem
Answer: c) Each party has a pair of keys: public and private
Explanation: Public key cryptography involves a pair of keys for each party: a public key used for encryption and a private key used for decryption.
3. The Diffie-Hellman key exchange is vulnerable to which problem?
a) RSA problem
b) Computational Diffie-Hellman problem
c) Discrete logarithm problem
d) Chinese Remainder Theorem
Answer: b) Computational Diffie-Hellman problem
Explanation: The Computational Diffie-Hellman problem involves calculating the shared secret key from the exchanged public keys in the Diffie-Hellman key exchange.
4. What is the main assumption underlying the RSA cryptosystem?
a) The difficulty of factoring large prime numbers
b) The hardness of solving discrete logarithm problems
c) The existence of a one-way function
d) The efficiency of elliptic curve cryptography
Answer: a) The difficulty of factoring large prime numbers
Explanation: RSA relies on the assumption that factoring large prime numbers is computationally difficult.
5. In RSA, what is used for encryption and decryption?
a) Only the public key
b) Only the private key
c) Both the public and private keys
d) Elliptic curves
Answer: c) Both the public and private keys
Explanation: In RSA, encryption is performed using the public key, while decryption is performed using the private key.
6. Which cryptographic scheme is used for digital signatures in RSA?
a) Schnorr Identification Scheme
b) Diffie-Hellman key exchange
c) Chinese Remainder Theorem
d) Elliptic curve cryptography
Answer: a) Schnorr Identification Scheme
Explanation: Schnorr Identification Scheme is often used for digital signatures in RSA.
7. What is primarily tested in the RSA cryptosystem?
a) Symmetric key encryption
b) Public key encryption
c) Asymmetric key encryption
d) Hash functions
Answer: b) Public key encryption
Explanation: RSA is primarily used for public key encryption and related cryptographic operations.
8. Which mathematical concept forms the basis of elliptic curve cryptography?
a) Quadratic residues
b) Discrete logarithm problem
c) Modular arithmetic
d) Factorization
Answer: b) Discrete logarithm problem
Explanation: The security of elliptic curve cryptography relies on the difficulty of solving the discrete logarithm problem over elliptic curves.
9. In elliptic curve cryptography, what is usually the modulus?
a) Prime numbers
b) Composite numbers
c) Real numbers
d) Imaginary numbers
Answer: a) Prime numbers
Explanation: In elliptic curve cryptography, the modulus is typically a prime number.
10. What mathematical concept does the Chinese Remainder Theorem utilize?
a) Modular arithmetic
b) Discrete logarithm problem
c) Prime factorization
d) Quadratic residues
Answer: a) Modular arithmetic
Explanation: The Chinese Remainder Theorem is based on modular arithmetic.
11. Which of the following is a characteristic of the Discrete Logarithm Problem (DLP)?
a) It is easy to solve for large prime numbers
b) It is computationally difficult to solve
c) It is only applicable to symmetric key encryption
d) It relies on factoring large composite numbers
Answer: b) It is computationally difficult to solve
Explanation: The Discrete Logarithm Problem (DLP) is known to be computationally difficult to solve, especially in certain mathematical groups.
12. What is the primary objective of the Diffie-Hellman key exchange?
a) To securely exchange symmetric keys
b) To encrypt messages using a shared secret key
c) To factor large prime numbers
d) To generate public and private key pairs
Answer: a) To securely exchange symmetric keys
Explanation: The primary goal of the Diffie-Hellman key exchange is to securely establish a shared secret key between two parties.
13. Which cryptographic scheme relies on the hardness of the discrete logarithm problem?
a) RSA
b) ElGamal
c) Diffie-Hellman
d) AES
Answer: b) ElGamal
Explanation: ElGamal encryption scheme relies on the hardness of the discrete logarithm problem in certain mathematical groups.
14. What is the main advantage of elliptic curve cryptography over RSA?
a) Faster key generation
b) Smaller key sizes for equivalent security
c) Stronger resistance to quantum attacks
d) More efficient decryption
Answer: b) Smaller key sizes for equivalent security
Explanation: Elliptic curve cryptography typically requires smaller key sizes compared to RSA for achieving equivalent security levels.
15. Which cryptographic scheme relies on the factorization problem?
a) Diffie-Hellman
b) RSA
c) ElGamal
d) Schnorr Identification Scheme
Answer: b) RSA
Explanation: RSA relies on the difficulty of factoring large composite numbers into their prime factors.
16. What role does the Chinese Remainder Theorem play in cryptography?
a) It facilitates key exchange
b) It speeds up encryption algorithms
c) It enables efficient decryption
d) It aids in modular arithmetic operations
Answer: c) It enables efficient decryption
Explanation: The Chinese Remainder Theorem is often used in cryptography to speed up decryption processes, especially in RSA and related schemes.
17. In which scenario is elliptic curve cryptography particularly advantageous?
a) When high computational power is available
b) When secure communication over the internet is required
c) When there is a need for large key sizes
d) When memory resources are limited
Answer: d) When memory resources are limited
Explanation: Elliptic curve cryptography is advantageous in scenarios where memory resources are limited because it requires smaller key sizes compared to other cryptographic schemes.
18. Which problem does RSA rely on for its security?
a) Diffie-Hellman problem
b) Computational Diffie-Hellman problem
c) Discrete logarithm problem
d) Factorization problem
Answer: d) Factorization problem
Explanation: RSA relies on the difficulty of factoring large composite numbers into their prime factors for its security.
19. Which cryptographic scheme is primarily used for symmetric key encryption?
a) RSA
b) Diffie-Hellman
c) AES
d) ElGamal
Answer: c) AES
Explanation: AES (Advanced Encryption Standard) is primarily used for symmetric key encryption.
20. What is the primary purpose of the Schnorr Identification Scheme?
a) Digital signatures
b) Key exchange
c) Encryption
d) Decryption
Answer: a) Digital signatures
Explanation: The Schnorr Identification Scheme is primarily used for digital signatures, providing a way for one party to prove to another that they possess a certain private key without revealing the key itself.