RFR: 8370082: Intermediate objects clean up in ECDH, XDH, DHKEM, and HKDF [v2]

[Artur Barashev]

On Wed, 22 Oct 2025 11:46:20 GMT, Weijun Wang <weijun at openjdk.org> wrote:

>> Clean up more intermediate objects created during these operations.
>
> Weijun Wang has updated the pull request incrementally with two additional commits since the last revision:
> 
>  - do not store key as bytes in XDH
>  - add ECDH and XDH

src/java.base/share/classes/com/sun/crypto/provider/DHKEM.java line 92:

> 90:             } finally {
> 91:                 if (key != null) {
> 92:                     Arrays.fill(key, (byte)0);

It's not immediately obvious to the caller that the key is being cloned in `SecretKeySpec` constructor. I think a short comment explaining what we are doing would be helpful here and below.

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PR Review Comment: https://git.openjdk.org/jdk/pull/27921#discussion_r2452216944