RFR: 8373426: Remove ffdhe6144 and ffdhe8192 from default list of TLS named groups

[Sean Mullan]

On Wed, 4 Feb 2026 19:29:02 GMT, Kirill Shirokov <kshiroko at openjdk.org> wrote:

> Removed FFDHE_6144 and FFHDE_8192 from the default list of TLS named groups, so now to consider them as candidates in TLS handshake user has to enable them explicitly (e.g. `-Djdk.tls.namedGroups=ffdhe6144,ffhde8192`)
> 
> Tested on Linux x64/aarch64, MacOS aarch64, Windows x64 using jtreg `test/jdk/sun/security/ssl` and `test/jdk/javax/net/ssl`.
> 
> [tests-linux-aarch64.log](https://github.com/user-attachments/files/25080233/tests-linux-aarch64.log)
> [tests-linux-x86.log](https://github.com/user-attachments/files/25080235/tests-linux-x86.log)
> [tests-macos-aarch64.log](https://github.com/user-attachments/files/25080236/tests-macos-aarch64.log)
> [tests-windows-x64.log](https://github.com/user-attachments/files/25080237/tests-windows-x64.log)

This will require a CSR, since it is a change to default behavior. The compatibility risk should be very low, since these named groups should rarely be used in practice.

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PR Comment: https://git.openjdk.org/jdk/pull/29577#issuecomment-3849524276