implement Router.sol and associated functions (#92)

* start Router contract

* use calldata for function args

* var name changes

* start testing router contract

* test with and without abi.encode

* cleanup

* why tf isn't tests/utils working

* cleanup tests

* remove unused files

* wip

* fix router contract and tests, add set/update public keys funcs

* impl some Froms

* make execute non-reentrant

* cleanup

* update Router to use ReentrancyGuard

* update contract to use errors, use bitfield in Executed event, minor other fixes

* wip

* fix build issues from merge, tests ok

* Router.sol cleanup

* cleanup, uncomment stuff

* bump ethers.rs version to latest

* make contract functions take generic middleware

* update build script to assert no compiler errors

* hardcode pubkey parity into contract, update tests

* Polish coins/ethereum in various ways

---------

Co-authored-by: Luke Parker <lukeparker5132@gmail.com>

coins/ethereum/src/tests/crypto.rs

@@ -0,0 +1,132 @@
+use rand_core::OsRng;
+
+use sha2::Sha256;
+use sha3::{Digest, Keccak256};
+
+use group::Group;
+use k256::{
+  ecdsa::{hazmat::SignPrimitive, signature::DigestVerifier, SigningKey, VerifyingKey},
+  elliptic_curve::{bigint::ArrayEncoding, ops::Reduce, point::DecompressPoint},
+  U256, Scalar, AffinePoint, ProjectivePoint,
+};
+
+use frost::{
+  curve::Secp256k1,
+  algorithm::{Hram, IetfSchnorr},
+  tests::{algorithm_machines, sign},
+};
+
+use crate::{crypto::*, tests::key_gen};
+
+pub fn hash_to_scalar(data: &[u8]) -> Scalar {
+  Scalar::reduce(U256::from_be_slice(&keccak256(data)))
+}
+
+pub(crate) fn ecrecover(message: Scalar, v: u8, r: Scalar, s: Scalar) -> Option<[u8; 20]> {
+  if r.is_zero().into() || s.is_zero().into() || !((v == 27) || (v == 28)) {
+    return None;
+  }
+
+  #[allow(non_snake_case)]
+  let R = AffinePoint::decompress(&r.to_bytes(), (v - 27).into());
+  #[allow(non_snake_case)]
+  if let Some(R) = Option::<AffinePoint>::from(R) {
+    #[allow(non_snake_case)]
+    let R = ProjectivePoint::from(R);
+
+    let r = r.invert().unwrap();
+    let u1 = ProjectivePoint::GENERATOR * (-message * r);
+    let u2 = R * (s * r);
+    let key: ProjectivePoint = u1 + u2;
+    if !bool::from(key.is_identity()) {
+      return Some(address(&key));
+    }
+  }
+
+  None
+}
+
+#[test]
+fn test_ecrecover() {
+  let private = SigningKey::random(&mut OsRng);
+  let public = VerifyingKey::from(&private);
+
+  // Sign the signature
+  const MESSAGE: &[u8] = b"Hello, World!";
+  let (sig, recovery_id) = private
+    .as_nonzero_scalar()
+    .try_sign_prehashed_rfc6979::<Sha256>(&Keccak256::digest(MESSAGE), b"")
+    .unwrap();
+
+  // Sanity check the signature verifies
+  #[allow(clippy::unit_cmp)] // Intended to assert this wasn't changed to Result<bool>
+  {
+    assert_eq!(public.verify_digest(Keccak256::new_with_prefix(MESSAGE), &sig).unwrap(), ());
+  }
+
+  // Perform the ecrecover
+  assert_eq!(
+    ecrecover(
+      hash_to_scalar(MESSAGE),
+      u8::from(recovery_id.unwrap().is_y_odd()) + 27,
+      *sig.r(),
+      *sig.s()
+    )
+    .unwrap(),
+    address(&ProjectivePoint::from(public.as_affine()))
+  );
+}
+
+// Run the sign test with the EthereumHram
+#[test]
+fn test_signing() {
+  let (keys, _) = key_gen();
+
+  const MESSAGE: &[u8] = b"Hello, World!";
+
+  let algo = IetfSchnorr::<Secp256k1, EthereumHram>::ietf();
+  let _sig =
+    sign(&mut OsRng, &algo, keys.clone(), algorithm_machines(&mut OsRng, &algo, &keys), MESSAGE);
+}
+
+#[allow(non_snake_case)]
+pub fn preprocess_signature_for_ecrecover(
+  R: ProjectivePoint,
+  public_key: &PublicKey,
+  chain_id: U256,
+  m: &[u8],
+  s: Scalar,
+) -> (u8, Scalar, Scalar) {
+  let c = EthereumHram::hram(
+    &R,
+    &public_key.A,
+    &[chain_id.to_be_byte_array().as_slice(), &keccak256(m)].concat(),
+  );
+  let sa = -(s * public_key.px);
+  let ca = -(c * public_key.px);
+  (public_key.parity, sa, ca)
+}
+
+#[test]
+fn test_ecrecover_hack() {
+  let (keys, public_key) = key_gen();
+
+  const MESSAGE: &[u8] = b"Hello, World!";
+  let hashed_message = keccak256(MESSAGE);
+  let chain_id = U256::ONE;
+  let full_message = &[chain_id.to_be_byte_array().as_slice(), &hashed_message].concat();
+
+  let algo = IetfSchnorr::<Secp256k1, EthereumHram>::ietf();
+  let sig = sign(
+    &mut OsRng,
+    &algo,
+    keys.clone(),
+    algorithm_machines(&mut OsRng, &algo, &keys),
+    full_message,
+  );
+
+  let (parity, sa, ca) =
+    preprocess_signature_for_ecrecover(sig.R, &public_key, chain_id, MESSAGE, sig.s);
+  let q = ecrecover(sa, parity, public_key.px, ca).unwrap();
+  assert_eq!(q, address(&sig.R));
+}