RFR: 8314323: Implement JEP 527: TLS 1.3 Hybrid Key Exchange [v11]

[Sean Mullan]

On Thu, 4 Dec 2025 00:03:49 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 one additional commit since the last revision:
> 
>   Remove null check to not assume key is returned

src/java.base/share/classes/sun/security/ssl/DHasKEM.java line 79:

> 77:     // It registers Hybrid KeyPairGenerator, KeyFactory, and KEM
> 78:     // implementations for hybrid named groups as Provider services.
> 79:     private static class ProviderImpl extends Provider {

This provider is not DH specific so doesn't fit right with being in this class. Move this `Provider` out into a separate class and call it `HybridProvider`, or alternatively put it inside the `Hybrid` class (so it would be `Hybrid.ProviderImpl`.) I know it also contains DHasKEM, which is not hybrid, but that is the only case, so I still think Hybrid is a suitable name, with a comment explaining there is one exception.

src/java.base/share/classes/sun/security/ssl/DHasKEM.java line 83:

> 81:         private static final long serialVersionUID = 0L;
> 82:         private ProviderImpl() {
> 83:             super("InternalJCEDHasKEM", PROVIDER_VER,

This provider supports more than DH, so suggest calling this "HybridAndDHAsKEM" or something like that.

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PR Review Comment: https://git.openjdk.org/jdk/pull/27614#discussion_r2589205332
PR Review Comment: https://git.openjdk.org/jdk/pull/27614#discussion_r2589211009