Start modularizing FROST tests as per https://github.com/serai-dex/serai/issues/9

crypto/frost/src/tests/literal/secp256k1.rs

@@ -0,0 +1,114 @@
+use core::convert::TryInto;
+
+use rand::rngs::OsRng;
+
+use ff::PrimeField;
+use group::GroupEncoding;
+
+use sha2::{Digest, Sha256, Sha512};
+
+use k256::{
+  elliptic_curve::{generic_array::GenericArray, bigint::{ArrayEncoding, U512}, ops::Reduce},
+  Scalar,
+  ProjectivePoint
+};
+
+use crate::{CurveError, Curve, multiexp_vartime, algorithm::Hram, tests::curve::test_curve};
+
+#[derive(Clone, Copy, PartialEq, Eq, Debug)]
+pub struct Secp256k1;
+impl Curve for Secp256k1 {
+  type F = Scalar;
+  type G = ProjectivePoint;
+  type T = ProjectivePoint;
+
+  fn id() -> String {
+    "secp256k1".to_string()
+  }
+
+  fn id_len() -> u8 {
+    Self::id().len() as u8
+  }
+
+  fn generator() -> Self::G {
+    Self::G::GENERATOR
+  }
+
+  fn generator_table() -> Self::T {
+    Self::G::GENERATOR
+  }
+
+  fn multiexp_vartime(scalars: &[Self::F], points: &[Self::G]) -> Self::G {
+    multiexp_vartime(scalars, points, false)
+  }
+
+  // The IETF draft doesn't specify a secp256k1 ciphersuite
+  // This test just uses the simplest ciphersuite which would still be viable to deploy
+  fn hash_msg(msg: &[u8]) -> Vec<u8> {
+    (&Sha256::digest(msg)).to_vec()
+  }
+
+  // Use wide reduction for security
+  fn hash_to_F(data: &[u8]) -> Self::F {
+    Scalar::from_uint_reduced(
+      U512::from_be_byte_array(Sha512::new().chain_update("rho").chain_update(data).finalize())
+    )
+  }
+
+  fn F_len() -> usize {
+    32
+  }
+
+  fn G_len() -> usize {
+    33
+  }
+
+  fn F_from_slice(slice: &[u8]) -> Result<Self::F, CurveError> {
+    let bytes: [u8; 32] = slice.try_into()
+      .map_err(|_| CurveError::InvalidLength(32, slice.len()))?;
+    let scalar = Scalar::from_repr(bytes.into());
+    if scalar.is_none().unwrap_u8() == 1 {
+      Err(CurveError::InvalidScalar)?;
+    }
+    Ok(scalar.unwrap())
+  }
+
+  fn G_from_slice(slice: &[u8]) -> Result<Self::G, CurveError> {
+    let point = ProjectivePoint::from_bytes(GenericArray::from_slice(slice));
+    if point.is_none().unwrap_u8() == 1 {
+      Err(CurveError::InvalidScalar)?;
+    }
+    Ok(point.unwrap())
+  }
+
+  fn F_to_bytes(f: &Self::F) -> Vec<u8> {
+    (&f.to_bytes()).to_vec()
+  }
+
+  fn G_to_bytes(g: &Self::G) -> Vec<u8> {
+    (&g.to_bytes()).to_vec()
+  }
+}
+
+#[allow(non_snake_case)]
+#[derive(Clone)]
+pub struct TestHram {}
+impl Hram<Secp256k1> for TestHram {
+  #[allow(non_snake_case)]
+  fn hram(R: &ProjectivePoint, A: &ProjectivePoint, m: &[u8]) -> Scalar {
+    Scalar::from_uint_reduced(
+      U512::from_be_byte_array(
+        Sha512::new()
+          .chain_update(Secp256k1::G_to_bytes(R))
+          .chain_update(Secp256k1::G_to_bytes(A))
+          .chain_update(m)
+          .finalize()
+      )
+    )
+  }
+}
+
+#[test]
+fn secp256k1_curve() {
+  test_curve::<_, Secp256k1>(&mut OsRng);
+}