RFR: 8314323: Implement JEP 527: TLS 1.3 Hybrid Key Exchange [v5]

[Artur Barashev]

On Tue, 14 Oct 2025 22:58:47 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:
> 
>   Fix typo in NamedGroup test

src/java.base/share/classes/sun/security/ssl/ServerHello.java line 577:

> 575:             //  Both peers perform similar operations: generate a public key,
> 576:             //  send it, and compute a shared secret upon receiving the peer's
> 577:             //  public key.

Nit: We use both `public key` and `key share` in this comment when describing Traditional Key Agreement. I think we should use only `key share`  (as in RFC 8446) when describing a traditional key exchange to avoid any confusion with KEM's public key.

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PR Review Comment: https://git.openjdk.org/jdk/pull/27614#discussion_r2430718513