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/bitcoin/src/tests/crypto.rs

@@ -0,0 +1,46 @@
+use rand_core::OsRng;
+
+use secp256k1::{Secp256k1 as BContext, Message, schnorr::Signature};
+
+use k256::Scalar;
+use transcript::{Transcript, RecommendedTranscript};
+use frost::{
+  curve::Secp256k1,
+  Participant,
+  tests::{algorithm_machines, key_gen, sign},
+};
+
+use crate::{
+  bitcoin::hashes::{Hash as HashTrait, sha256::Hash},
+  crypto::{x_only, make_even, Schnorr},
+};
+
+#[test]
+fn test_algorithm() {
+  let mut keys = key_gen::<_, Secp256k1>(&mut OsRng);
+  const MESSAGE: &[u8] = b"Hello, World!";
+
+  for keys in keys.values_mut() {
+    let (_, offset) = make_even(keys.group_key());
+    *keys = keys.offset(Scalar::from(offset));
+  }
+
+  let algo =
+    Schnorr::<RecommendedTranscript>::new(RecommendedTranscript::new(b"bitcoin-serai sign test"));
+  let sig = sign(
+    &mut OsRng,
+    &algo,
+    keys.clone(),
+    algorithm_machines(&mut OsRng, &algo, &keys),
+    Hash::hash(MESSAGE).as_ref(),
+  );
+
+  BContext::new()
+    .verify_schnorr(
+      &Signature::from_slice(&sig)
+        .expect("couldn't convert produced signature to secp256k1::Signature"),
+      &Message::from_digest_slice(Hash::hash(MESSAGE).as_ref()).unwrap(),
+      &x_only(&keys[&Participant::new(1).unwrap()].group_key()),
+    )
+    .unwrap()
+}