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/monero/generators/src/hash_to_point.rs

@@ -0,0 +1,53 @@
+use subtle::ConditionallySelectable;
+
+use curve25519_dalek::edwards::EdwardsPoint;
+
+use group::ff::{Field, PrimeField};
+use dalek_ff_group::FieldElement;
+
+use monero_io::decompress_point;
+
+use crate::keccak256;
+
+/// Monero's `hash_to_ec` function.
+pub fn hash_to_point(bytes: [u8; 32]) -> EdwardsPoint {
+  #[allow(non_snake_case)]
+  let A = FieldElement::from(486662u64);
+
+  let v = FieldElement::from_square(keccak256(&bytes)).double();
+  let w = v + FieldElement::ONE;
+  let x = w.square() + (-A.square() * v);
+
+  // This isn't the complete X, yet its initial value
+  // We don't calculate the full X, and instead solely calculate Y, letting dalek reconstruct X
+  // While inefficient, it solves API boundaries and reduces the amount of work done here
+  #[allow(non_snake_case)]
+  let X = {
+    let u = w;
+    let v = x;
+    let v3 = v * v * v;
+    let uv3 = u * v3;
+    let v7 = v3 * v3 * v;
+    let uv7 = u * v7;
+    uv3 * uv7.pow((-FieldElement::from(5u8)) * FieldElement::from(8u8).invert().unwrap())
+  };
+  let x = X.square() * x;
+
+  let y = w - x;
+  let non_zero_0 = !y.is_zero();
+  let y_if_non_zero_0 = w + x;
+  let sign = non_zero_0 & (!y_if_non_zero_0.is_zero());
+
+  let mut z = -A;
+  z *= FieldElement::conditional_select(&v, &FieldElement::from(1u8), sign);
+  #[allow(non_snake_case)]
+  let Z = z + w;
+  #[allow(non_snake_case)]
+  let mut Y = z - w;
+
+  Y *= Z.invert().unwrap();
+  let mut bytes = Y.to_repr();
+  bytes[31] |= sign.unwrap_u8() << 7;
+
+  decompress_point(bytes).unwrap().mul_by_cofactor()
+}