xmss: bind WOTS recover_public_key to self.randomness, drop mismatched signature param

Co-Authored-By: Nikos Baxevanis <nikos.baxevanis@gmail.com>

Author: TomWambsgans

crates/xmss/src/wots.rs

@@ -75,9 +75,8 @@ impl WotsSignature {
         message: &[F; MESSAGE_LEN_FE],
         slot: u32,
         xmss_pub_key: &XmssPublicKey,
-        signature: &Self,
     ) -> Option<WotsPublicKey> {
-        let encoding = wots_encode(message, slot, xmss_pub_key, &signature.randomness)?;
+        let encoding = wots_encode(message, slot, xmss_pub_key, &self.randomness)?;
         Some(WotsPublicKey(std::array::from_fn(|i| {
             iterate_hash(
                 &self.chain_tips[i],

crates/xmss/src/xmss.rs

@@ -211,7 +211,7 @@ pub fn xmss_verify(
 ) -> Result<(), XmssVerifyError> {
     let wots_public_key = signature
         .wots_signature
-        .recover_public_key(message, slot, pub_key, &signature.wots_signature)
+        .recover_public_key(message, slot, pub_key)
         .ok_or(XmssVerifyError::InvalidWots)?;
     let mut current_hash = wots_public_key.hash(pub_key.public_param, slot);
     for (level, neighbour) in signature.merkle_proof.iter().enumerate() {