Hi Sebastian, I'm back from my vacation. Thanks for the update.
I agree, using NamedKey is probably a better choice anyway. It's nice that getParams() always return a name and we don't need to call getAlgorithm() as a fallback. Thanks, Weijun > On Jun 30, 2025, at 06:06, Sebastian Stenzel <sebastian.sten...@gmail.com> > wrote: > > Quoting Bas Westerbaan (in CC) again, we will most likely see further PQ/T > hybrids from the IETF crypto forum research group (CFRG for short): > >> It seems likely that the CFRG will at some point produce a P-384+ML-KEM-1024 >> hybrid. See >> https://mailarchive.ietf.org/arch/msg/cfrg/CwrVvm-J7o85TEWkG9RJxZwfXDY/ . >> That might take some time. >> >> Very few (but notably Ericsson) have asked for X448 hybrids, so I don't >> expect them soon. > > That said, the construction does not necessarily be compatible to X-Wing. > Just to be sure, I asked whether they see any value in parameterizing X-Wing > to swap out algorithms. This is what Bas replied: > >> Even if the other hybrids will also use an X-Wing style combiner, it doesn't >> hurt not to parametrize initially. :) > > So I would suggest to follow this advice for now and only refactor the > implementation eventually, when further pairs of algorithms are combined in > the same way. > > Best, > Sebastian > > >> On 29. Jun 2025, at 12:02, Sebastian Stenzel <sebastian.sten...@gmail.com> >> wrote: >> >> >>> On 28. Jun 2025, at 00:12, Wei-Jun Wang <weijun.w...@oracle.com> wrote: >>> >>> [...] After all, there is no parameter for X-Wing. Did you hear the authors >>> they want to introduce other algorithms like ed448 and ML-KEM-1024 into it? >> >> I forwarded this question and let you know the answer! >> >> >>>> >>>>> On 7. Jun 2025, at 23:34, Wei-Jun Wang <weijun.w...@oracle.com> wrote: >>>>> >>>>> Cool. >>>>> >>>>> The current NamedPKCS8Key was designed based on an older approach where >>>>> modern asymmetric keys store private key data in a nested OCTET STRING >>>>> format. This pattern was introduced with EdDSA and XDH, and at the time >>>>> of JDK 24, we anticipated it would become the norm. >>>>> >>>>> However, things have changed significantly, as seen in the evolution of >>>>> draft-ietf-lamps-dilithium-certificates and >>>>> draft-ietf-lamps-kyber-certificates. The original design now needs to be >>>>> revised. While we’re still waiting for the IETF drafts to be finalized, >>>>> we’re already experimenting with changes in >>>>> https://github.com/openjdk/jdk/pull/24969. >>>>> >>>>> Hopefully, by the time X-Wing is finalized, we’ll already have a solution >>>>> in place. >>>>> >>>>> Thanks, >>>>> Weijun >>>>> >>>>>> On Jun 7, 2025, at 16:14, Sebastian Stenzel >>>>>> <sebastian.sten...@gmail.com> wrote: >>>>>> >>>>>> Hi Weijun, >>>>>> >>>>>> I got a mostly working implementation based on NamedKEM [0], however to >>>>>> fulfil the spec I need your advice: >>>>>> >>>>>> The (current) X-Wing spec wants this PKCS#8 encoding: [1] >>>>>> >>>>>> However, the NamedPKCS8Key implementation always puts a nested >>>>>> OctetString into the private key part. [2] >>>>>> >>>>>> Note the difference here: >>>>>> * >>>>>> https://lapo.it/asn1js/#MDQCAQAwDQYLKwYBBAGD5i2ByHoEIAABAgMEBQYHCAkKCwwNDg8QERITFBUWFxgZGhscHR4f >>>>>> * >>>>>> https://lapo.it/asn1js/#MDYCAQAwDQYLKwYBBAGD5i2ByHoEIgQg9IFQEyQtdLJL8j-hRm6Yzx3CzFiDyNk4yCADl6ZiXWo >>>>>> >>>>>> I believe we need some more flexibility, as the ASN.1 standard leaves it >>>>>> open to the algorithms how a private key is formatted. What do you think >>>>>> how to approach this? >>>>>> >>>>>> Or should I ask the authors whether they have a specific encoding in >>>>>> mind? The ASN.1 definitions in the spec don’t seem to be complete yet. >>>>>> >>>>>> Best regards, >>>>>> Sebastian >>>>>> >>>>>> [0]: >>>>>> https://github.com/openjdk/jdk/compare/master...overheadhunter:jdk:x-wing >>>>>> [1]: >>>>>> https://www.ietf.org/archive/id/draft-connolly-cfrg-xwing-kem-07.html#appendix-D >>>>>> [2]: >>>>>> https://github.com/openjdk/jdk/blob/d7352559195b9e052c3eb24d773c0d6c10dc23ad/src/java.base/share/classes/sun/security/pkcs/NamedPKCS8Key.java#L76-L81 >>>>>> >>>>>>> On 30. May 2025, at 15:03, Wei-Jun Wang <weijun.w...@oracle.com> wrote: >>>>>>> >>>>>>> >>>>>>> >>>>>>>> On May 30, 2025, at 08:40, Sebastian Stenzel >>>>>>>> <sebastian.sten...@gmail.com> wrote: >>>>>>>> >>>>>>>> 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? >>>>>>> >>>>>>> Feel free to start a draft if you’d like. I'll create a JBS issue once >>>>>>> we decide we want to include it in the JDK. >>>>>>> >>>>>>>> >>>>>>>> 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. >>>>>>> >>>>>>> I see. >>>>>>> >>>>>>>> >>>>>>>> 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] >>>>>>> >>>>>>> Nice to know. Sorry I didn't noticed that earlier. >>>>>>> >>>>>>> Thanks, >>>>>>> Weijun >>>>>>> >>>>>>>> >>>>>>>> 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 >>>>>>>>>> >>>>>>>>> >>>>>>>> >>>>>>> >>>>>> >>>>> >>>> >>> >> >
