Revert "Implement a FROST algorithm for Schnorrkel"

This reverts commit 8ef8b5ca6f.

crypto/schnorrkel/src/lib.rs

@@ -1,133 +0,0 @@
-use std::io::{self, Read};
-
-use rand_core::{RngCore, CryptoRng};
-
-use zeroize::Zeroizing;
-
-use group::{ff::PrimeField, GroupEncoding};
-use ciphersuite::{Ciphersuite, Ristretto};
-use schnorr::SchnorrSignature;
-use frost::{
-  ThresholdKeys, ThresholdView, FrostError,
-  algorithm::{IetfTranscript, Hram, Algorithm, Schnorr},
-};
-
-use schnorrkel::{PublicKey, Signature, context::SigningTranscript, signing_context};
-
-type RistrettoPoint = <Ristretto as Ciphersuite>::G;
-type Scalar = <Ristretto as Ciphersuite>::F;
-
-#[cfg(test)]
-mod tests;
-
-#[derive(Clone)]
-struct SchnorrkelHram;
-impl Hram<Ristretto> for SchnorrkelHram {
-  #[allow(non_snake_case)]
-  fn hram(R: &RistrettoPoint, A: &RistrettoPoint, m: &[u8]) -> Scalar {
-    let ctx_len =
-      usize::try_from(u32::from_le_bytes(m[0 .. 4].try_into().expect("malformed message")))
-        .unwrap();
-    let mut t = signing_context(&m[4 .. (4 + ctx_len)]).bytes(&m[(4 + ctx_len) ..]);
-    t.proto_name(b"Schnorr-sig");
-    let convert =
-      |point: &RistrettoPoint| PublicKey::from_bytes(&point.to_bytes()).unwrap().into_compressed();
-    t.commit_point(b"sign:pk", &convert(A));
-    t.commit_point(b"sign:R", &convert(R));
-    Scalar::from_repr(t.challenge_scalar(b"sign:c").to_bytes()).unwrap()
-  }
-}
-
-#[derive(Clone)]
-pub struct Schnorrkel {
-  context: &'static [u8],
-  schnorr: Schnorr<Ristretto, SchnorrkelHram>,
-  msg: Option<Vec<u8>>,
-}
-
-impl Schnorrkel {
-  pub fn new(context: &'static [u8]) -> Schnorrkel {
-    Schnorrkel { context, schnorr: Schnorr::new(), msg: None }
-  }
-}
-
-impl Algorithm<Ristretto> for Schnorrkel {
-  type Transcript = IetfTranscript;
-  type Addendum = ();
-  type Signature = Signature;
-
-  fn transcript(&mut self) -> &mut Self::Transcript {
-    self.schnorr.transcript()
-  }
-
-  fn nonces(&self) -> Vec<Vec<<Ristretto as Ciphersuite>::G>> {
-    self.schnorr.nonces()
-  }
-
-  fn preprocess_addendum<R: RngCore + CryptoRng>(
-    &mut self,
-    _: &mut R,
-    _: &ThresholdKeys<Ristretto>,
-  ) {
-  }
-
-  fn read_addendum<R: Read>(&self, _: &mut R) -> io::Result<Self::Addendum> {
-    Ok(())
-  }
-
-  fn process_addendum(
-    &mut self,
-    _: &ThresholdView<Ristretto>,
-    _: u16,
-    _: (),
-  ) -> Result<(), FrostError> {
-    Ok(())
-  }
-
-  fn sign_share(
-    &mut self,
-    params: &ThresholdView<Ristretto>,
-    nonce_sums: &[Vec<<Ristretto as Ciphersuite>::G>],
-    nonces: Vec<Zeroizing<<Ristretto as Ciphersuite>::F>>,
-    msg: &[u8],
-  ) -> <Ristretto as Ciphersuite>::F {
-    self.msg = Some(msg.to_vec());
-    self.schnorr.sign_share(
-      params,
-      nonce_sums,
-      nonces,
-      &[
-        &u32::try_from(self.context.len()).expect("context exceeded 2^32 bytes").to_le_bytes(),
-        self.context,
-        msg,
-      ]
-      .concat(),
-    )
-  }
-
-  #[must_use]
-  fn verify(
-    &self,
-    group_key: <Ristretto as Ciphersuite>::G,
-    nonces: &[Vec<<Ristretto as Ciphersuite>::G>],
-    sum: <Ristretto as Ciphersuite>::F,
-  ) -> Option<Self::Signature> {
-    let mut sig = (SchnorrSignature::<Ristretto> { R: nonces[0][0], s: sum }).serialize();
-    sig[63] |= 1 << 7;
-    Some(Signature::from_bytes(&sig).unwrap()).filter(|sig| {
-      PublicKey::from_bytes(&group_key.to_bytes())
-        .unwrap()
-        .verify(&mut signing_context(self.context).bytes(self.msg.as_ref().unwrap()), sig)
-        .is_ok()
-    })
-  }
-
-  fn verify_share(
-    &self,
-    verification_share: <Ristretto as Ciphersuite>::G,
-    nonces: &[Vec<<Ristretto as Ciphersuite>::G>],
-    share: <Ristretto as Ciphersuite>::F,
-  ) -> Result<Vec<(<Ristretto as Ciphersuite>::F, <Ristretto as Ciphersuite>::G)>, ()> {
-    self.schnorr.verify_share(verification_share, nonces, share)
-  }
-}

crypto/schnorrkel/src/tests.rs

@@ -1,14 +0,0 @@
-use rand_core::OsRng;
-
-use frost::tests::{key_gen, algorithm_machines, sign};
-
-use crate::Schnorrkel;
-
-#[test]
-fn test() {
-  let keys = key_gen(&mut OsRng);
-  const CONTEXT: &[u8] = b"FROST Schnorrkel Test";
-  let machines = algorithm_machines(&mut OsRng, Schnorrkel::new(CONTEXT), &keys);
-  const MSG: &[u8] = b"Hello, World!";
-  sign(&mut OsRng, Schnorrkel::new(CONTEXT), keys, machines, MSG);
-}