RFR: 8331008: Implement JEP 478: Key Derivation Function API (Preview) [v43]

[Valerie Peng]

On Wed, 18 Sep 2024 21:44:08 GMT, Valerie Peng <valeriep at openjdk.org> wrote:

>> Kevin Driver has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   refinement of addIKM and addSalt specifications
>
> src/java.base/share/classes/com/sun/crypto/provider/HKDFKeyDerivation.java line 92:
> 
>> 90:         }
>> 91:         this.hmacAlgName = hmacAlgName;
>> 92:         this.hmacLen = hmacLen;
> 
> Instead of doing a binary search whenever an HKDFKeyDerivation object is constructed, it is better to organize the algorithm and output length into an enum, this way, supporting new Hmac algorithms would require adding new enum value. This should be sufficient since these arguments are internally supplied. For example,
> 
> public enum SupportedHmac {
>         SHA256("HmacSHA256", 32),
>         SHA384("HmacSHA384", 48),
>         SHA512("HmacSHA512", 64);
> 
>         public final String algo;
>         public final int outLen;
>         private SupportedHmac(String algo, int outLen) {
>             this.algo = algo;
>             this.outLen = outLen;
>         }
>  };

Then the constructor can specify enum as the argument, e.g. 

    private HKDFKeyDerivation(SupportedHmac h,
                              KDFParameters kdfParameters)
            throws InvalidAlgorithmParameterException {
        super(kdfParameters);
        if (kdfParameters != null) {
            throw new InvalidAlgorithmParameterException(
                    h.algo + " does not support parameters");
        }
        this.hmacAlgName = h.algo;
        this.hmacLen = h.outLen;
    }

> src/java.base/share/classes/com/sun/crypto/provider/HKDFKeyDerivation.java line 396:
> 
>> 394:         public HKDFSHA256(KDFParameters kdfParameters)
>> 395:                 throws InvalidAlgorithmParameterException {
>> 396:             super("HmacSHA256", SHA256_HMAC_SIZE, kdfParameters);
> 
> Using the enum, this line would be:
> `            super(SupportedHmac.SHA256, kdfParameters);`

Similar changes to the other child classes below.

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PR Review Comment: https://git.openjdk.org/jdk/pull/20301#discussion_r1765767539
PR Review Comment: https://git.openjdk.org/jdk/pull/20301#discussion_r1765769023