RFR: 8331008: Implement JEP 478: Key Derivation Function API (Preview) [v24]

[Viktor Klang]

On Thu, 5 Sep 2024 23:17:32 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 with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains 31 additional commits since the last revision:
> 
>  - Merge remote-tracking branch 'origin/master' into kdf-jep-wip
>    # Please enter a commit message to explain why this merge is necessary,
>    # especially if it merges an updated upstream into a topic branch.
>    #
>    # Lines starting with '#' will be ignored, and an empty message aborts
>    # the commit.
>  - several more review comments
>  - change impl class to use byte arrays rather than SecretKey objects where possible
>  - updated delayed provider selection javadoc
>  - review comments
>  - use a delegate record to hold the spi and provider
>  - assorted review comment changes
>  - another round of review comments
>  - consistency with wording for addIKM and addSalt
>  - another round of code review comments
>  - ... and 21 more: https://git.openjdk.org/jdk/compare/84bfac65...a35e98c9

src/java.base/share/classes/com/sun/crypto/provider/HkdfKeyDerivation.java line 70:

> 68:      */
> 69:     HkdfKeyDerivation(String hmacAlgName, int hmacLen,
> 70:                       KDFParameters kdfParameters)

Why does this take KDFParameters if hmacAlgName doesn't support parameters?

src/java.base/share/classes/com/sun/crypto/provider/HkdfKeyDerivation.java line 134:

> 132:         byte[] salt;
> 133:         byte[] pseudoRandomKey;
> 134:         byte[] info;

Might be cleaner to declare it as:

Suggestion:

        List<SecretKey> ikms, salts;
        byte[] inputKeyMaterial, salt, pseudoRandomKey, info;

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PR Review Comment: https://git.openjdk.org/jdk/pull/20301#discussion_r1747074863
PR Review Comment: https://git.openjdk.org/jdk/pull/20301#discussion_r1747077429