RFR: 8314323: Implement JEP 527: TLS 1.3 Hybrid Key Exchange [v6]

[Xue-Lei Andrew Fan]

On Wed, 15 Oct 2025 06:48:50 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 two additional commits since the last revision:
> 
>  - Revert changes to UseStrongDHSizes test as ffdhe6144/8192 added back
>  - Updated comment in ServerHello and hybrid to upper-case in NamedGroup

src/java.base/share/classes/sun/security/util/Hybrid.java line 178:

> 176:                 throws InvalidKeySpecException {
> 177:             if (keySpec instanceof RawKeySpec rks) {
> 178:                 byte[] key = rks.getKeyArr();

null check on key may be missed.  If the API expose to public in the future, the key length checking may be good before Arrays.copyOfRange.

-------------

PR Review Comment: https://git.openjdk.org/jdk/pull/27614#discussion_r2464374013