Struct sigma_fun::HashTranscript

pub struct HashTranscript<H, R = ()> { /* private fields */ }

A transcript which consists of a hash with fixed length output and a seedable RNG.

The SeedableRng specified must have the same seed length as the hash’s output length. R may be set to () but the it won’t implement ProverTranscript.

Trait Implementations

impl<H: Clone, R: Clone> Clone for HashTranscript<H, R>

fn clone(&self) -> HashTranscript<H, R>

Returns a copy of the value.

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

Performs copy-assignment from source.

impl<H: Debug, R: Debug> Debug for HashTranscript<H, R>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<H: Default, R> Default for HashTranscript<H, R>

fn default() -> Self

Returns the “default value” for a type.

impl<S, H, R> ProverTranscript<S> for HashTranscript<H, R> where
    S: Sigma,
    H: Update + FixedOutput<OutputSize = U32> + Clone,
    R: SeedableRng + CryptoRng + RngCore + Clone,
    R::Seed: From<GenericArray<u8, U32>>, 

Implements a prover transcript for a 32-byte hash with a rng that takes a 32-byte seed.

type Rng = R

The type of Rng the transcript generates.

fn gen_rng<SysRng: CryptoRng + RngCore>(
    &self,
    sigma: &S,
    witness: &S::Witness,
    in_rng: Option<&mut SysRng>
) -> Self::Rng

Generates an RNG from the transcript state and an input rng (in_rng) which should provide system randomness.

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.

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,
    announce: &S::Announcement
) -> GenericArray<u8, S::ChallengeLength>

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