Kyber
The official reference implementation of the Kyber key encapsulation mechanism, from the pq-crystals team.
Why this is listed
The reference implementation is the whole repository rather than a component of a product, and its LICENSE offers it under CC0 or Apache 2.0, which is both limbs of this rule.
The repository describes itself as the official reference implementation of the Kyber key encapsulation mechanism, and states that Kyber was selected for standardisation in round 3 of the NIST post-quantum cryptography standardization project. It sits under the pq-crystals organisation, alongside the Dilithium repository.
Not maintained for production, on the team's own notice
The repository states that the team no longer actively maintains this software, at least not to the extent that would be necessary to recommend it for production use, and points readers at mlkem-native and mlkem-libjade instead. A reference implementation earns its place by being readable and correct, which is not the same job as being maintained.
Its LICENSE file offers the code either as public domain under CC0 or under the Apache 2.0 licence, and notes that the Keccak and AES code it uses is public domain from sources credited at the top of those files.
Sources
Checked against these sources on Sep 4, 2026. Listing is not endorsement, and nothing here is ranked or scored.