CRYSTALS-Dilithium is primarily used for which purpose?

• A. Digital signatures
• B. Key exchange
• C. Encryption
• D. Hashing

Answer: (A)

CRYSTALS-Dilithium is a lattice-based digital signature scheme. Its main purpose is to allow someone to sign a message with a private signing key, so others can verify the signature using the corresponding public key. This provides authenticity (you can be sure who signed it), integrity (the message hasn’t been altered), and non-repudiation (the signer can’t convince others they didn’t sign it). It’s specifically designed for securing signatures in a post-quantum era, unlike encryption or key-exchange schemes.

It isn’t used for establishing a shared secret between parties—that role is filled by key-exchange or key encapsulation methods such as CRYSTALS-Kyber. It also isn’t the primary tool for confidentiality, since encryption schemes are what provide encryption of message content. Hash functions are related in signing processes, but the core purpose of Dilithium is to enable verifiable digital signatures.