Dilithium

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A rust implementation of the Dilithium, a KEM standardised by the NIST Post-Quantum Standardization Project.

See the features section for different options regarding security levels and modes of operation. The default security setting is Dilithium3.

It is recommended to use Dilithium in a hybrid system alongside a traditional signature algorithm such as ed25519.

Minimum Supported Rust Version: 1.50.0


Installation

shell cargo add pqc_dilithium

Usage

rust use pqc_dilithium::*;

Key Generation

rust let keys = Keypair::generate(); assert!(keys.public.len() == PUBLICKEYBYTES); assert!(keys.expose_secret().len() == SECRETKEYBYTES);

Signing

rust let msg = "Hello".as_bytes(); let sig = keys.sign(&msg); assert!(sig.len() == SIGNBYTES);

Verification

rust let sig_verify = verify(&sig, &msg, &keys.public); assert!(sig_verify.is_ok());


AES mode

Dilithium-AES, that uses AES-256 in counter mode instead of SHAKE to expand the matrix and the masking vectors, and to sample the secret polynomials. This offers hardware speedups on certain platforms.


Randomized signing

One may want to consider randomized signatures in situations where the side channel attacks of [SBB+18, PSS+18] exploiting determinism are applicable. Another situation where one may want to avoid determinism is when the signer does not wish to reveal the message that is being signed. While there is no timing leakage of the secret key, there is timing leakage of the message if the scheme is deterministic. Since the randomness of the scheme is derived from the message, the number of aborts for a particular message will always be the same.


Features

By default this library uses Dilithium3

| Name | Description | |----------------|-------------------------------------------------------------------------------------------------------------------| | mode2 | Uses Dilithium2 | | mode5 | Uses Dilithium5 | | aes | Uses AES256-CTR instead of SHAKE | | random_signing | Enables randomized signing of messages |


Testing

To run the known answer tests, you'll need to enable the dilithium_kat config flag eg.

shell RUSTFLAGS="--cfg dilithium_kat" cargo test

To run through all possible features use the test_matrix.sh script.


Alternatives

The PQClean project has rust bindings for their C post quantum libraries.

https://github.com/rustpq/pqcrypto/tree/main/pqcrypto-dilithium


About

Dilithium is a digital signature scheme that is strongly secure under chosen message attacks based on the hardness of lattice problems over module lattices. The security notion means that an adversary having access to a signing oracle cannot produce a signature of a message whose signature he hasn't yet seen, nor produce a different signature of a message that he already saw signed. Dilithium has been standardised by the NIST post-quantum cryptography project.

The official website: https://pq-crystals.org/dilithium/

Authors of the Dilithium Algorithm:


Contributing

Contributions welcome. For pull requests create a feature fork, by submitting PR's you agree for the code to be dual licensed under MIT/Apache 2.0