Trait schnorrkel::context::SigningTranscript

source · [−]
pub trait SigningTranscript {
    fn commit_bytes(&mut self, label: &'static [u8], bytes: &[u8]);

    fn challenge_bytes(&mut self, label: &'static [u8], dest: &mut [u8]);

    fn witness_bytes_rng<R>(
        &self, 
        label: &'static [u8], 
        dest: &mut [u8], 
        nonce_seeds: &[&[u8]], 
        rng: R
    )
    where
        R: RngCore + CryptoRng;

    fn proto_name(&mut self, label: &'static [u8]) { ... }

    fn commit_point(
        &mut self, 
        label: &'static [u8], 
        compressed: &CompressedRistretto
    ) { ... }

    fn challenge_scalar(&mut self, label: &'static [u8]) -> Scalar { ... }

    fn witness_scalar(
        &self, 
        label: &'static [u8], 
        nonce_seeds: &[&[u8]]
    ) -> Scalar { ... }

    fn witness_bytes(
        &self, 
        label: &'static [u8], 
        dest: &mut [u8], 
        nonce_seeds: &[&[u8]]
    ) { ... }
}
Expand description

Schnorr signing transcript

We envision signatures being on messages, but if a signature occurs inside a larger protocol then the signature scheme’s internal transcript may exist before or persist after signing.

In this trait, we provide an interface for Schnorr signature-like constructions that is compatable with merlin::Transcript, but abstract enough to support conventional hash functions as well.

We warn however that conventional hash functions do not provide strong enough domain seperation for usage via &mut references.

We fold randomness into witness generation here too, which gives every function that takes a SigningTranscript a default argument rng: impl Rng = thread_rng() too.

We also abstract over owned and borrowed merlin::Transcripts, so that simple use cases do not suffer from our support for.

Required methods

Extend transcript with some bytes, shadowed by merlin::Transcript.

Produce some challenge bytes, shadowed by merlin::Transcript.

Produce secret witness bytes from the protocol transcript and any “nonce seeds” kept with the secret keys.

Provided methods

Extend transcript with a protocol name

Extend the transcript with a compressed Ristretto point

Produce the public challenge scalar e.

Produce a secret witness scalar k, aka nonce, from the protocol transcript and any “nonce seeds” kept with the secret keys.

Produce secret witness bytes from the protocol transcript and any “nonce seeds” kept with the secret keys.

Implementations on Foreign Types

We delegates any mutable reference to its base type, like &mut Rng or similar to BorrowMut<..> do, but doing so here simplifies alternative implementations.

We delegate SigningTranscript methods to the corresponding inherent methods of merlin::Transcript and implement two witness methods to avoid abrtasting the merlin::TranscriptRng machenry.

Implementors