Keccak uses a different domain separation byte as the NIST-
standardized SHA-3 hashing function. A previous commit to
this package added support for Keccak-256, but did not do
so for Keccak-512. The reasoning was to support use cases
like Ethereum, however Ethereum also uses Keccak-512 for
the Ethash PoW, so this second method is also needed.
Prev CL: https://go-review.googlesource.com/c/crypto/+/106462Fixesgolang/go#29533
Change-Id: I9d92b1f121657f631c157e5e309771db1cd91c82
Reviewed-on: https://go-review.googlesource.com/c/125795
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
1. API:
This exposes a minimal API: the SHA-3 functions implement hash.Hash. The
SHAKE functions implement a new "ShakeHash" interface that implements
io.Reader, io.Writer, and Reset().
(The previous Barrier() function has been removed.)
(Alternative proposal: Don't implement io.Reader, but instead provide a
"Digest(d []byte) error" function that performs a hash.Hash style copy.
Somewhat more minimal, but very easy to use incorrectly.)
2. Tests
Added the complete set of ShortMsgKATs from
https://github.com/gvanas/KeccakCodePackage
3. Correctness
In sync with draft FIPS-202.
4. Documentation
A summary of the security properties of the SHA-3 and SHAKE functions is
provided in doc.go; some concrete recommendations as well.
Fixes 8563.
R=golang-codereviews, agl
CC=golang-codereviews
https://golang.org/cl/130950043