RFR: 8353578: Refactor existing usage of internal HKDF impl to use the KDF API [v6]

[Sean Mullan]

On Tue, 29 Apr 2025 21:44:26 GMT, Valerie Peng <valeriep at openjdk.org> wrote:

>> This PR removes the internal JSSE HKDF impl and changes to use the KDF API for the HKDF support from JCA/JCE providers.
>> 
>> This is just code refactoring. Known-answer regression test for the internal JSSE HKDF impl is removed as the test vectors are already covered by the HKDF impl in SunJCE provider.
>> 
>> Thanks in advance for the review~
>
> Valerie Peng has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Add comment about not using the same HKDF instance.

src/java.base/share/classes/sun/security/ssl/ServerHello.java line 624:

> 622: 
> 623:             SSLKeyDerivation handshakeKD = ke.createKeyDerivation(shc);
> 624:             SecretKey handshakeSecret = handshakeKD.deriveKey(

It looks like this can be cleared after it is used to derive the key. Similar comment on line 1310.

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PR Review Comment: https://git.openjdk.org/jdk/pull/24393#discussion_r2068969063