Which of the following is a digital signature scheme based on lattice problems?

• A. CRYSTALS-Dilithium
• B. SPHINCS+
• C. CRYSTALS-Kyber
• D. SHA-256

Answer: (A)

Lattice-based digital signatures rely on hard problems in lattice cryptography, offering potential quantum resistance. CRYSTALS-Dilithium is a digital signature scheme built on lattice problems (notably SIS/LWE in a module-lattice setting), designed specifically for signing messages with efficient verification while providing strong security against quantum attacks. SPHINCS+ is also a signature scheme, but it uses only hash-based techniques—Merkle trees and cryptographic hash functions—rather than lattice problems. CRYSTALS-Kyber, on the other hand, is a lattice-based public-key encryption (a KEM) scheme, not a signature scheme. SHA-256 is a cryptographic hash function, not a signature mechanism. So CRYSTALS-Dilithium is the lattice-based digital signature choice.