Trait Hasher

pub trait Hasher:
    Clone
    + Send
    + 'static {
    // Required methods
    fn new() -> Self;
    fn update(&mut self, message: &[u8]);
    fn finalize(&mut self) -> Digest;
    fn reset(&mut self);
    fn validate(digest: &Digest) -> bool;
    fn len() -> usize;
    fn random<R: Rng + CryptoRng>(rng: &mut R) -> Digest;
}

Interface that commonware crates rely on for hashing.

Hash functions in commonware primitives are not typically hardcoded to a specific algorithm (e.g. SHA-256) because different hash functions may work better with different cryptographic schemes, may be more efficient to use in STARK/SNARK proofs, or provide different levels of security (with some performance/size penalty).

This trait is required to implement the Clone trait because it is often part of a struct that is cloned. In practice, implementations do not actually clone the hasher state but users should not rely on this behavior and call reset after cloning.

Required Methods

fn new() -> Self

Create a new hasher.

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

Append message to previously recorded data.

fn finalize(&mut self) -> Digest

Hash all recorded data and reset the hasher to the initial state.

fn reset(&mut self)

Reset the hasher without generating a hash.

This function does not need to be called after finalize.

fn validate(digest: &Digest) -> bool

Validate the digest.

fn len() -> usize

Size of the digest in bytes.

fn random<R: Rng + CryptoRng>(rng: &mut R) -> Digest

Generate a random digest.

Warning

This function is typically used for testing and is not recommended for production use.

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementors

impl Hasher for Sha256