Struct sigma_fun::HashTranscript

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

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>

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

Returns a copy of the value.

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

Performs copy-assignment from source.

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

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

Formats the value using the given formatter.

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

pub 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.

pub 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 tags the SHA256 instance with the Sigma protocol's name.

pub fn initialize(&mut self, sigma: &S)

Initializes the transcript. This must be called once when the prover is created. It shouldn't be called before each proof. Rather it should be called once and then the transcript should be cloned for each proof.

pub 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.

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

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