Update how x coordinates are handled in bitcoin-serai

networks/bitcoin/src/wallet/mod.rs

@@ -39,9 +39,9 @@ pub use send::*;
 /// from being spent via a script. To have keys which have spendable script paths, further offsets
 /// from this position must be used.
 ///
-/// After adding an unspendable script path, the key is incremented until its even. This means the
-/// existence of the unspendable script path may not provable, without an understanding of the
-/// algorithm used here.
+/// After adding an unspendable script path, the key is negated if odd.
+///
+/// This has a neligible probability of returning keys whose group key is the point at infinity.
 #[cfg(feature = "std")]
 pub fn tweak_keys(keys: ThresholdKeys<Secp256k1>) -> ThresholdKeys<Secp256k1> {
   // Adds the unspendable script path per

networks/bitcoin/src/wallet/send.rs

@@ -288,7 +288,7 @@ impl SignableTransaction {
 /// A FROST signing machine to produce a Bitcoin transaction.
 ///
 /// This does not support caching its preprocess. When sign is called, the message must be empty.
-/// This will panic if either `cache` is called or the message isn't empty.
+/// This will panic if either `cache`, `from_cache` is called or the message isn't empty.
 pub struct TransactionMachine {
   tx: SignableTransaction,
   sigs: Vec<AlgorithmMachine<Secp256k1, Schnorr>>,