Struct CShake128 

pub struct CShake128 { /* private fields */ }

SP 800-185 cSHAKE128: SHAKE128 with a customization string.

Implementations

impl CShake128

pub const RATE: usize = 168

The sponge rate in bytes, which is also bytepad’s width here.

pub fn new(n: &[u8], s: &[u8]) -> Self

Start a cSHAKE with a function name n and customization s.

n is reserved for NIST-defined functions — KMAC passes "KMAC". Application customization belongs in s.

With both empty this is plain SHAKE, per SP 800-185 section 3.3, including the domain separator.

pub fn update(&mut self, data: &[u8])

Absorb more input.

pub fn finalize_xof(self, out: &mut [u8])

Squeeze out.len() bytes.

pub fn xof(n: &[u8], s: &[u8], data: &[u8], out: &mut [u8])

One-shot.

pub fn absorb_bytepadded_string(&mut self, s: &[u8])

Absorb bytepad(encode_string(s), RATE).

KMAC prefixes its message with the key encoded exactly this way. It is exposed here rather than rebuilt in ic-mac because the padding width is the sponge rate, which is cSHAKE’s property and not the caller’s to know.

Trait Implementations

impl Algorithm for CShake128

const ID: &'static str = "cshake128"

Stable ontology identifier for this algorithm.

const NAME: &'static str = "cSHAKE128"

Human-facing display name (for example "SHA-256").

impl Clone for CShake128

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl SelfTest for CShake128

fn self_test() -> Result<()>

Two checks, neither of which needs a vector this code produced.

With no customization cSHAKE must equal SHAKE exactly, and SHAKE has its own CAST against a published FIPS 202 answer — so this inherits that evidence. Then customization must change the output, which catches a build where the prefix was silently dropped and every customized call collapsed onto plain SHAKE.