Inline the eVRF into the DKG library

Due to how we're handling share encryption, we'd either need two circuits or to
dedicate this circuit to the DKG. The latter makes sense at this time.

crypto/dkg/src/tests/evrf/proof.rs

@@ -0,0 +1,89 @@
+use std::time::Instant;
+
+use rand_core::OsRng;
+
+use zeroize::{Zeroize, Zeroizing};
+use generic_array::typenum::{Sum, Diff, Quot, U, U1, U2};
+use blake2::{Digest, Blake2b512};
+
+use ciphersuite::{
+  group::ff::{FromUniformBytes, PrimeField},
+  Ciphersuite,
+};
+use pasta_curves::{Ep, Eq, Fp, Fq};
+
+use generalized_bulletproofs::tests::generators;
+
+use crate::*;
+
+#[derive(Clone, Copy, PartialEq, Eq, Debug, Zeroize)]
+struct Pallas;
+impl Ciphersuite for Pallas {
+  type F = Fq;
+  type G = Ep;
+  type H = Blake2b512;
+  const ID: &'static [u8] = b"Pallas";
+  fn generator() -> Ep {
+    Ep::generator()
+  }
+  fn hash_to_F(dst: &[u8], msg: &[u8]) -> Self::F {
+    // This naive concat may be insecure in a real world deployment
+    // This is solely test code so it's fine
+    Self::F::from_uniform_bytes(&Self::H::digest([dst, msg].concat()).into())
+  }
+}
+
+#[derive(Clone, Copy, PartialEq, Eq, Debug, Zeroize)]
+struct Vesta;
+impl Ciphersuite for Vesta {
+  type F = Fp;
+  type G = Eq;
+  type H = Blake2b512;
+  const ID: &'static [u8] = b"Vesta";
+  fn generator() -> Eq {
+    Eq::generator()
+  }
+  fn hash_to_F(dst: &[u8], msg: &[u8]) -> Self::F {
+    // This naive concat may be insecure in a real world deployment
+    // This is solely test code so it's fine
+    Self::F::from_uniform_bytes(&Self::H::digest([dst, msg].concat()).into())
+  }
+}
+
+struct VestaParams;
+impl DiscreteLogParameters for VestaParams {
+  type ScalarBits = U<{ <<Vesta as Ciphersuite>::F as PrimeField>::NUM_BITS as usize }>;
+  type XCoefficients = Quot<Sum<Self::ScalarBits, U1>, U2>;
+  type XCoefficientsMinusOne = Diff<Self::XCoefficients, U1>;
+  type YxCoefficients = Diff<Quot<Sum<Self::ScalarBits, U1>, U2>, U2>;
+}
+
+impl EvrfCurve for Pallas {
+  type EmbeddedCurve = Vesta;
+  type EmbeddedCurveParameters = VestaParams;
+}
+
+#[test]
+fn pasta_test() {
+  let generators = generators(1024);
+  let vesta_private_key = Zeroizing::new(<Vesta as Ciphersuite>::F::random(&mut OsRng));
+  let time = Instant::now();
+  let res =
+    Evrf::prove::<Pallas>(&mut OsRng, &generators, vesta_private_key.clone(), [0; 32], 1).unwrap();
+  println!("Proving time: {:?}", Instant::now() - time);
+
+  let time = Instant::now();
+  let mut verifier = generators.batch_verifier();
+  dbg!(Evrf::verify::<Pallas>(
+    &mut OsRng,
+    &generators,
+    &mut verifier,
+    Vesta::generator() * *vesta_private_key,
+    [0; 32],
+    1,
+    &res.proof,
+  )
+  .unwrap());
+  assert!(generators.verify(verifier));
+  println!("Verifying time: {:?}", Instant::now() - time);
+}