Hi Weijun, waiting for the final standard is understandable. The internals may still change, but the „outer hull“ of the PR is something that could already be discussed before - under these premises, would it make sense to already start a draft? Knowing that it won’t be merged yet?
I have a working set of KeyPairGenerator, KeyFactory and KEM SPI including test vectors basically ready - just SHAKE256 currently borrowed from BC. I know that using SHAKE256 within the JDK is not a problem. However if we want to make it public, there simply *is no* XOF API in JCA. Technically the expand step of the KDF API can be used, but semantically that would be a misuse. Adding a completely new API is nothing I currently want to work on. Btw I am somewhat familiar with the development process as I have started contributing to the JDK in 2021 on cipher and NIO issues. [1] Thank you, Sebastian [1] https://github.com/openjdk/jdk/pulls?q=is%3Apr+author%3Aoverheadhunter > On 29. May 2025, at 18:44, Wei-Jun Wang <weijun.w...@oracle.com> wrote: > > Hi Sebastian. > >> On May 24, 2025, at 05:40, Sebastian Stenzel <sebastian.sten...@gmail.com> >> wrote: >> >> Hi all, >> >> For the past few months I have been in contact with one of the authors of >> two spec drafts for future JOSE encryption standards [1] [2] with the latter >> of them relying on X-Wing. >> >> As the X-Wing spec doesn’t face significant changes any more (there have >> been some larger shifts in regards to secret key derivation last year), I am >> now tasked to create a prototype implementation for these RFCs. > > Thanks for your continued interest on enhancing OpenJDK. > > That said, we have a policy of not implementing algorithms that haven't been > standardized. So we won't be able to consider your contribution until IETF > publishes draft-connolly-cfrg-xwing-kem as an RFC. I'm not sure how familiar > you are with the OpenJDK developing process, but in the meantime, you might > find it helpful to read the OpenJDK Developers’ Guide [1] and try working on > something smaller first. > >> >> All the primitives for X-Wing are technically already there in OpenJDK, >> however two of them are private API (namely SHAKE256 and ML-KEM’s >> `KeyGen_internal(d, z)` [3]). So the question arises whether I can >> contribute an X-Wing KEM implementation to the JDK at the current state of >> the spec? > > It's acceptable to use private API inside OpenJDK when you are working on > OpenJDK itself. After all, we created them for this very purpose. However, > please keep in mind that this means you bind your X-Wing implementation to > the SunJCE/SunEC implementations. Usually, as a higher-level algorithm, if > its underlying algorithms could be implemented by different security > providers, it will be nice to make it provider-neutral where possible. > >> >> Alternatively, can we make the two mentioned APIs public? > > No. These methods are too specific to their respective algorithms. We prefer > JCA/JCE-style API that is algorithm-neutral. > > [1] https://openjdk.org/guide/ > > Thanks, > Weijun > >> >> Cheers! >> Sebastian >> >> [1]: https://datatracker.ietf.org/doc/html/draft-ietf-jose-hpke-encrypt/ >> [2]: >> https://datatracker.ietf.org/doc/html/draft-reddy-cose-jose-pqc-hybrid-hpke-07 >> [3]: >> https://github.com/openjdk/jdk/blob/070c84cd22485a93a562a7639439fb056e840861/src/java.base/share/classes/com/sun/crypto/provider/ML_KEM.java#L498-L536 >> >
