RFR: 8331008: Implement JEP 478: Key Derivation Function API (Preview) [v22]

[Viktor Klang]

On Fri, 30 Aug 2024 23:26:12 GMT, Kevin Driver <kdriver at openjdk.org> wrote:

>> Introduce an API for Key Derivation Functions (KDFs), which are cryptographic algorithms for deriving additional keys from a secret key and other data. See [JEP 478](https://openjdk.org/jeps/478).
>> 
>> Work was begun in [another PR](https://github.com/openjdk/jdk/pull/18924).
>
> Kevin Driver has updated the pull request incrementally with one additional commit since the last revision:
> 
>   change impl class to use byte arrays rather than SecretKey objects where possible

src/java.base/share/classes/com/sun/crypto/provider/HkdfKeyDerivation.java line 167:

> 165:                 // Since we're defining these values internally, it is unlikely.
> 166:                 throw new ProviderException(
> 167:                     "could not instantiate a Mac with the provided algorithm",

There's a bit of inconsistency in using capitalization on abbreviations, examples are: "HKDF" vs "Mac"/"Hmac" vs "ikm". I'd suggest aligning with prior art and use that consistently.

src/java.base/share/classes/com/sun/crypto/provider/HkdfKeyDerivation.java line 354:

> 352:                 // sized the buffers to their largest possible size up-front,
> 353:                 // but just in case...
> 354:                 throw new RuntimeException(sbe);

If this is truly something which should not be possible, it might be better to throw an InternalError.

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PR Review Comment: https://git.openjdk.org/jdk/pull/20301#discussion_r1745737456
PR Review Comment: https://git.openjdk.org/jdk/pull/20301#discussion_r1745742211