Rename the coins folder to networks (#583)

* Rename the coins folder to networks

Ethereum isn't a coin. It's a network.

Resolves #357.

* More renames of coins -> networks in orchestration

* Correct paths in tests/

* cargo fmt

networks/ethereum/src/crypto.rs

@@ -0,0 +1,188 @@
+use group::ff::PrimeField;
+use k256::{
+  elliptic_curve::{ops::Reduce, point::AffineCoordinates, sec1::ToEncodedPoint},
+  ProjectivePoint, Scalar, U256 as KU256,
+};
+#[cfg(test)]
+use k256::{elliptic_curve::point::DecompressPoint, AffinePoint};
+
+use frost::{
+  algorithm::{Hram, SchnorrSignature},
+  curve::{Ciphersuite, Secp256k1},
+};
+
+use alloy_core::primitives::{Parity, Signature as AlloySignature};
+use alloy_consensus::{SignableTransaction, Signed, TxLegacy};
+
+use crate::abi::router::{Signature as AbiSignature};
+
+pub(crate) fn keccak256(data: &[u8]) -> [u8; 32] {
+  alloy_core::primitives::keccak256(data).into()
+}
+
+pub(crate) fn hash_to_scalar(data: &[u8]) -> Scalar {
+  <Scalar as Reduce<KU256>>::reduce_bytes(&keccak256(data).into())
+}
+
+pub fn address(point: &ProjectivePoint) -> [u8; 20] {
+  let encoded_point = point.to_encoded_point(false);
+  // Last 20 bytes of the hash of the concatenated x and y coordinates
+  // We obtain the concatenated x and y coordinates via the uncompressed encoding of the point
+  keccak256(&encoded_point.as_ref()[1 .. 65])[12 ..].try_into().unwrap()
+}
+
+/// Deterministically sign a transaction.
+///
+/// This function panics if passed a transaction with a non-None chain ID.
+pub fn deterministically_sign(tx: &TxLegacy) -> Signed<TxLegacy> {
+  assert!(
+    tx.chain_id.is_none(),
+    "chain ID was Some when deterministically signing a TX (causing a non-deterministic signer)"
+  );
+
+  let sig_hash = tx.signature_hash().0;
+  let mut r = hash_to_scalar(&[sig_hash.as_slice(), b"r"].concat());
+  let mut s = hash_to_scalar(&[sig_hash.as_slice(), b"s"].concat());
+  loop {
+    let r_bytes: [u8; 32] = r.to_repr().into();
+    let s_bytes: [u8; 32] = s.to_repr().into();
+    let v = Parity::NonEip155(false);
+    let signature =
+      AlloySignature::from_scalars_and_parity(r_bytes.into(), s_bytes.into(), v).unwrap();
+    let tx = tx.clone().into_signed(signature);
+    if tx.recover_signer().is_ok() {
+      return tx;
+    }
+
+    // Re-hash until valid
+    r = hash_to_scalar(r_bytes.as_ref());
+    s = hash_to_scalar(s_bytes.as_ref());
+  }
+}
+
+/// The public key for a Schnorr-signing account.
+#[allow(non_snake_case)]
+#[derive(Clone, Copy, PartialEq, Eq, Debug)]
+pub struct PublicKey {
+  pub(crate) A: ProjectivePoint,
+  pub(crate) px: Scalar,
+}
+
+impl PublicKey {
+  /// Construct a new `PublicKey`.
+  ///
+  /// This will return None if the provided point isn't eligible to be a public key (due to
+  /// bounds such as parity).
+  #[allow(non_snake_case)]
+  pub fn new(A: ProjectivePoint) -> Option<PublicKey> {
+    let affine = A.to_affine();
+    // Only allow even keys to save a word within Ethereum
+    let is_odd = bool::from(affine.y_is_odd());
+    if is_odd {
+      None?;
+    }
+
+    let x_coord = affine.x();
+    let x_coord_scalar = <Scalar as Reduce<KU256>>::reduce_bytes(&x_coord);
+    // Return None if a reduction would occur
+    // Reductions would be incredibly unlikely and shouldn't be an issue, yet it's one less
+    // headache/concern to have
+    // This does ban a trivial amoount of public keys
+    if x_coord_scalar.to_repr() != x_coord {
+      None?;
+    }
+
+    Some(PublicKey { A, px: x_coord_scalar })
+  }
+
+  pub fn point(&self) -> ProjectivePoint {
+    self.A
+  }
+
+  pub(crate) fn eth_repr(&self) -> [u8; 32] {
+    self.px.to_repr().into()
+  }
+
+  #[cfg(test)]
+  pub(crate) fn from_eth_repr(repr: [u8; 32]) -> Option<Self> {
+    #[allow(non_snake_case)]
+    let A = Option::<AffinePoint>::from(AffinePoint::decompress(&repr.into(), 0.into()))?.into();
+    Option::from(Scalar::from_repr(repr.into())).map(|px| PublicKey { A, px })
+  }
+}
+
+/// The HRAm to use for the Schnorr contract.
+#[derive(Clone, Default)]
+pub struct EthereumHram {}
+impl Hram<Secp256k1> for EthereumHram {
+  #[allow(non_snake_case)]
+  fn hram(R: &ProjectivePoint, A: &ProjectivePoint, m: &[u8]) -> Scalar {
+    let x_coord = A.to_affine().x();
+
+    let mut data = address(R).to_vec();
+    data.extend(x_coord.as_slice());
+    data.extend(m);
+
+    <Scalar as Reduce<KU256>>::reduce_bytes(&keccak256(&data).into())
+  }
+}
+
+/// A signature for the Schnorr contract.
+#[derive(Clone, Copy, PartialEq, Eq, Debug)]
+pub struct Signature {
+  pub(crate) c: Scalar,
+  pub(crate) s: Scalar,
+}
+impl Signature {
+  pub fn verify(&self, public_key: &PublicKey, message: &[u8]) -> bool {
+    #[allow(non_snake_case)]
+    let R = (Secp256k1::generator() * self.s) - (public_key.A * self.c);
+    EthereumHram::hram(&R, &public_key.A, message) == self.c
+  }
+
+  /// Construct a new `Signature`.
+  ///
+  /// This will return None if the signature is invalid.
+  pub fn new(
+    public_key: &PublicKey,
+    message: &[u8],
+    signature: SchnorrSignature<Secp256k1>,
+  ) -> Option<Signature> {
+    let c = EthereumHram::hram(&signature.R, &public_key.A, message);
+    if !signature.verify(public_key.A, c) {
+      None?;
+    }
+
+    let res = Signature { c, s: signature.s };
+    assert!(res.verify(public_key, message));
+    Some(res)
+  }
+
+  pub fn c(&self) -> Scalar {
+    self.c
+  }
+  pub fn s(&self) -> Scalar {
+    self.s
+  }
+
+  pub fn to_bytes(&self) -> [u8; 64] {
+    let mut res = [0; 64];
+    res[.. 32].copy_from_slice(self.c.to_repr().as_ref());
+    res[32 ..].copy_from_slice(self.s.to_repr().as_ref());
+    res
+  }
+
+  pub fn from_bytes(bytes: [u8; 64]) -> std::io::Result<Self> {
+    let mut reader = bytes.as_slice();
+    let c = Secp256k1::read_F(&mut reader)?;
+    let s = Secp256k1::read_F(&mut reader)?;
+    Ok(Signature { c, s })
+  }
+}
+impl From<&Signature> for AbiSignature {
+  fn from(sig: &Signature) -> AbiSignature {
+    let c: [u8; 32] = sig.c.to_repr().into();
+    let s: [u8; 32] = sig.s.to_repr().into();
+    AbiSignature { c: c.into(), s: s.into() }
+  }
+}