RFR: 8331008: Implement JEP 478: Key Derivation Function API (Preview) [v37]

[Weijun Wang]

On Fri, 13 Sep 2024 22:36:15 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:
> 
>   remove unused debug field

src/java.base/share/classes/javax/crypto/KDF.java line 670:

> 668:             }
> 669:         }
> 670:         throw new InvalidAlgorithmParameterException(

Should this ever happen? We already made sure `firstPairOfSpiAndProv` is for this algorithm and we have tried calling `deriveXyz` on it. Therefore there must be a `lastException` now. In the lines above, you checked two types of `lastException`. Is that exhaustive? If not, can you wrap it into an IAPE and throw it there?

Also, even if `deriveXyz` finally fails, we still have to complete the DPS process, i.e. assign something to `pairOfSpiAndProv`, since DPS should only be run once. Later calls to `getProviderName` still need a return value.

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PR Review Comment: https://git.openjdk.org/jdk/pull/20301#discussion_r1761122332