RFR: 8331008: Implement JEP 478: Key Derivation Function API (Preview) [v10]

[Kevin Driver]

On Fri, 16 Aug 2024 18:18:51 GMT, Valerie Peng <valeriep at openjdk.org> wrote:

>> src/java.base/share/classes/com/sun/crypto/provider/HkdfKeyDerivation.java line 258:
>> 
>>> 256:                 byte[] workItemBytes = CipherCore.getKeyBytes(checkIt);
>>> 257:                 return new SecretKeySpec(workItemBytes, "Generic");
>>> 258:             } else {
>> 
>> I think this is less error prone and easier to read than what you have below:
>> 
>>                 ByteArrayOutputStream os = new ByteArrayOutputStream();
>>                 for (SecretKey workItem : localKeys) {
>>                     try {
>>                         os.write(CipherCore.getKeyBytes(workItem));
>>                     } catch (IOException e) {
>>                         // won't happen
>>                     }
>>                 }
>>                 return new SecretKeySpec(os.toByteArray(), "Generic");
>> 
>> And if your concerned about the extra copy from `toByteArray()`, you could consider using an internal class `AEADBufferedStream` which extends ByteArrayOutputStream but will return the internal copy to avoid extra mem allocation.
>
> +1.

Addressed in https://github.com/openjdk/jdk/pull/20301/commits/48395b86ba8e1cda663ae326e06ae2556f4b905a. Please indicate if this is resolved.

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PR Review Comment: https://git.openjdk.org/jdk/pull/20301#discussion_r1722375664