Implement Lelantus Spark's Chaum Pedersen proof with a FROST algorithm

crypto/frost/src/algorithm.rs

@@ -52,6 +52,7 @@ pub trait Algorithm<C: Curve>: Clone {
   /// verification fails
   fn verify_share(
     &self,
+    l: u16,
     verification_share: C::G,
     nonce: C::G,
     share: C::F,
@@ -154,6 +155,7 @@ impl<C: Curve, H: Hram<C>> Algorithm<C> for Schnorr<C, H> {
 
   fn verify_share(
     &self,
+    _: u16,
     verification_share: C::G,
     nonce: C::G,
     share: C::F,

crypto/frost/src/sign.rs

@@ -217,6 +217,7 @@ fn complete<C: Curve, A: Algorithm<C>>(
   // within n / 2 on average, and not gameable to n, though that should be minor
   for l in &sign_params.view.included {
     if !sign_params.algorithm.verify_share(
+      *l,
       sign_params.view.verification_share(*l),
       sign.B[l][0] + (sign.B[l][1] * sign.binding),
       responses[l]