Struct BHP

pub struct BHP<E: Environment, const NUM_WINDOWS: u8, const WINDOW_SIZE: u8> { /* private fields */ }

BHP is a collision-resistant hash function that takes a variable-length input. The BHP hash function does not behave like a random oracle, see Poseidon for one.

Design

The BHP hash function splits the given input into blocks, and processes them iteratively.

The first iteration is initialized as follows:

DIGEST_0 = BHP([ 0...0 || DOMAIN || LENGTH(INPUT) || INPUT[0..BLOCK_SIZE] ]);

Each subsequent iteration is initialized as follows:

DIGEST_N+1 = BHP([ DIGEST_N[0..DATA_BITS] || INPUT[(N+1)*BLOCK_SIZE..(N+2)*BLOCK_SIZE] ]);

Trait Implementations

impl<E: Environment, const NUM_WINDOWS: u8, const WINDOW_SIZE: u8> Commit for BHP<E, NUM_WINDOWS, WINDOW_SIZE>

fn commit( &self, input: &[Self::Input], randomizer: &Self::Randomizer, ) -> Self::Output

Returns the BHP commitment of the given input and randomizer as a field element.

type Input = Boolean<E>

type Output = Field<E>

type Randomizer = Scalar<E>

impl<E: Environment, const NUM_WINDOWS: u8, const WINDOW_SIZE: u8> CommitUncompressed for BHP<E, NUM_WINDOWS, WINDOW_SIZE>

fn commit_uncompressed( &self, input: &[Self::Input], randomizer: &Self::Randomizer, ) -> Self::Output

Returns the BHP commitment of the given input and randomizer as an affine group element.

type Input = Boolean<E>

type Output = Group<E>

type Randomizer = Scalar<E>

impl<E: Environment, const NUM_WINDOWS: u8, const WINDOW_SIZE: u8> Hash for BHP<E, NUM_WINDOWS, WINDOW_SIZE>

fn hash(&self, input: &[Self::Input]) -> Self::Output

Returns the BHP hash of the given input as a field element.

type Input = Boolean<E>

type Output = Field<E>

impl<E: Environment, const NUM_WINDOWS: u8, const WINDOW_SIZE: u8> HashUncompressed for BHP<E, NUM_WINDOWS, WINDOW_SIZE>

fn hash_uncompressed(&self, input: &[Self::Input]) -> Self::Output

Returns the BHP hash of the given input as an affine group element.

This uncompressed variant of the BHP hash function is provided to support the BHP commitment scheme, as it is typically not used by applications.

type Input = Boolean<E>

type Output = Group<E>

impl<E: Environment, const NUM_WINDOWS: u8, const WINDOW_SIZE: u8> Inject for BHP<E, NUM_WINDOWS, WINDOW_SIZE>

fn new(_mode: Mode, bhp: Self::Primitive) -> Self

Initializes a new instance of a BHP circuit with the given BHP variant.

type Primitive = BHP<<E as Environment>::Network, NUM_WINDOWS, WINDOW_SIZE>

fn constant(value: Self::Primitive) -> Self

where Self: Sized,

Initializes a constant of the given primitive value.