Lattice-Based and Post-Quantum Cryptography ECES Practice Questions (Page 6)

Questions 26–30

1. 26application · medium

   A cryptography engineer is explaining to management why lattice-based algorithms are considered quantum-resistant. The engineer needs to identify the core mathematical problem that makes these algorithms hard for quantum computers. Which problem should the engineer cite?

   • AThe subset sum problem
   • BThe Shortest Vector Problem (SVP) in high-dimensional lattices
   • CThe discrete logarithm problem
   • DThe integer factorization problem
   Reveal Solution Discussion Select an answer first
2. 27application · medium

   A security team is evaluating hash-based signature schemes for a long-term document archival system. They need signatures that remain secure for decades and are resistant to quantum attacks. They are considering SPHINCS+. Which property of SPHINCS+ makes it particularly suitable for this use case?

   • AIts security relies only on the collision resistance and preimage resistance of the underlying hash function, which are well-understood and conservative assumptions.
   • BIt has small signatures and fast verification, making it ideal for high-volume signing applications.
   • CIt uses a trapdoor function that is easy to compute in one direction but hard to invert, providing long-term security.
   • DIts security is based on the hardness of the Shortest Vector Problem (SVP), which is believed to be quantum-resistant.
   Reveal Solution Discussion Select an answer first
4. 28application · medium

   A security engineer is evaluating lattice-based signature schemes for a high-security application. They need a scheme that is resistant to quantum attacks and has fast verification. They are considering Dilithium and Falcon. Which statement correctly compares these two schemes?

   • ABoth schemes have identical performance and security characteristics, so the choice is irrelevant.
   • BDilithium is based on the hardness of the Shortest Vector Problem (SVP), while Falcon is based on the Learning With Errors (LWE) problem.
   • CDilithium has larger signatures but faster signing, while Falcon has smaller signatures but slower signing.
   • DFalcon has larger signatures but faster verification, while Dilithium has smaller signatures but slower verification.
   Reveal Solution Discussion Select an answer first
5. 29foundation · easy

   Which algorithm was selected by NIST for post-quantum key encapsulation?

   • ASPHINCS+
   • BFalcon
   • CKyber
   • DDilithium
   Reveal Solution Discussion Select an answer first
6. 30application · medium

   A research team is exploring isogeny-based cryptography for a new secure messaging application. They are considering SIKE (Supersingular Isogeny Key Encapsulation). Which statement correctly describes a notable advantage and a notable challenge of SIKE?

   • AAdvantage: simple implementation. Challenge: requires a trusted setup.
   • BAdvantage: very small key sizes. Challenge: slow performance compared to other post-quantum candidates.
   • CAdvantage: based on well-studied mathematical problems. Challenge: vulnerable to quantum attacks.
   • DAdvantage: fast performance. Challenge: large key sizes.
   Reveal Solution Discussion Select an answer first