RFR: 8331008: KDF Implementation

[Sibabrata Sahoo]

On Tue, 23 Apr 2024 20:42:51 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).

src/java.base/share/classes/com/sun/crypto/provider/HkdfKeyDerivation.java line 337:

> 335:         hmacObj.init(new SecretKeySpec(salt, "HKDF-Salt"));
> 336: 
> 337:         return hmacObj.doFinal(inputKey.getEncoded());

inputKey can possibly null because consolidateKeyMaterial() returns null when List<SecretKey> keys is null or empty.

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PR Review Comment: https://git.openjdk.org/jdk/pull/18924#discussion_r1595178690