Trait sigma_fun::Transcript

pub trait Transcript<S: Sigma>: Clone {
    fn add_name<N: Writable + ?Sized>(&mut self, name: &N);
    fn add_statement(&mut self, sigma: &S, statement: &S::Statement);
    fn get_challenge(
        self, 
        sigma: &S, 
        announcement: &S::Announcement
    ) -> GenericArray<u8, S::ChallengeLength>;
}

A trait for a Fiat-Shamir proof transcript.

Really this is just a trait around a cryptographic hash that can produce a Fiat-Shamir challenge from the statement and the announcement. The usual workflow is to call add_name and then clone the transcript for each new statement.

Required methods

fn add_name<N: Writable + ?Sized>(&mut self, name: &N)

The name unambigiously determines the semantics of the statement and announcement which are subsequently added to the transcript.

fn add_statement(&mut self, sigma: &S, statement: &S::Statement)

Adds the prover’s statement to the transcript. This must be called before get_challenge.

fn get_challenge(
    self,
    sigma: &S,
    announcement: &S::Announcement
) -> GenericArray<u8, S::ChallengeLength>

Gets the verifier’s synthetic challenge for the non-interactive proof.

Implementors

impl<H, S: Sigma, R: Clone> Transcript<S> for HashTranscript<H, R> where
    S::ChallengeLength: IsLessOrEqual<U32>,
    <S::ChallengeLength as IsLessOrEqual<U32>>::Output: NonZero,
    H: BlockInput<BlockSize = U64> + FixedOutput<OutputSize = U32> + Update + Default + Clone, 

Implements a transcript for any hash that outputs 32 bytes but with a block size of 64 bytes (e.g. SHA256).

The implementation first BIP-340 tags the SHA256 instance with the Sigma protocol’s name.