RFR: 8314323: Implement JEP 527: TLS 1.3 Hybrid Key Exchange [v9]

[Sean Mullan]

On Mon, 24 Nov 2025 07:51:40 GMT, Hai-May Chao <hchao at openjdk.org> wrote:

>> Implement hybrid key exchange support for TLS 1.3 by adding three post-quantum hybrid named groups: X25519MLKEM768, SecP256r1MLKEM768, and SecP384r1MLKEM1024.
>> Please see [JEP 527](https://openjdk.org/jeps/527) for details about this change.
>
> Hai-May Chao has updated the pull request incrementally with three additional commits since the last revision:
> 
>  - Update names to uppercase
>  - Remove fallback in engineGeneratePublic
>  - Change default named group list to have only X25519MLKEM768

src/java.base/share/classes/com/sun/crypto/provider/DH.java line 66:

> 64:  * KEMs.
> 65:  */
> 66: public class DH implements KEMSpi {

This class includes more than a DH KEM wrapper implementation. The provider is registering all the hybrid algorithms, including the ML-KEM parts. It feels odd to be hiding the provider inside this class. I suggest creating a separate `HybridProvider` class that is in `sun.security.ssl` package and either encapsulating the DH impl inside that, or better yet, create a separate class for it.

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PR Review Comment: https://git.openjdk.org/jdk/pull/27614#discussion_r2577735059