RFR: JDK-8338587 - Internal XOF Methods for SHAKE128 and SHAKE256 [v5]

[Valerie Peng]

On Wed, 28 Aug 2024 16:42:38 GMT, Ferenc Rakoczi <duke at openjdk.org> wrote:

>> In preparation for the new PQC algorithms implementations, internal XOF (eXtendable Output Function) methods are added to the SHAKE128 and SHAKE256 implementations.
>
> Ferenc Rakoczi has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Fixing typos and simplify the squeeze() method as suggested by Weijun

src/java.base/share/classes/sun/security/provider/SHA3.java line 70:

> 68:     };
> 69: 
> 70:     // the starting 3 or 5 bits of the domain separator and 10*1 padding

I find the current comment a bit confusing and kind of hard mapping to the spec. Spec states 2 or 4-bit suffix (01 for SHA-3 hash function and 1111 for XOF functions). Maybe something like following:
"The starting byte combining the 2 or 4-bit domain separator and 10*1 padding, see Table 6 in B.2 of FIPS PUB 202 for examples".
There is also comment above `setPaddingBytes()` about suffix, now that we added support for SHA-3 XOF, add suffix of "1111" to there as well?

src/java.base/share/classes/sun/security/provider/SHA3.java line 77:

> 75:     private long[] state = new long[DM*DM];
> 76: 
> 77:     // The byte offset in the state where the next sqeeze() will start.

typo: sqeeze -> squeeze

src/java.base/share/classes/sun/security/provider/SHA3.java line 169:

> 167:     }
> 168: 
> 169:     void implSqueeze(byte[]output, int offset, int numBytes) {

nit: add a space after `byte[]`.

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PR Review Comment: https://git.openjdk.org/jdk/pull/20631#discussion_r1735112019
PR Review Comment: https://git.openjdk.org/jdk/pull/20631#discussion_r1735113213
PR Review Comment: https://git.openjdk.org/jdk/pull/20631#discussion_r1744637008