handle message start with 0

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "multi-party-schnorr"
-version = "0.3.2"
+version = "0.3.3"
 authors = [
     "Omer <omer@kzencorp.com>",
     "Gary <gary@kzencorp.com>"
@@ -12,11 +12,11 @@ crate-type = ["lib"]
 [dependencies]
 serde = "1.0"
 serde_derive = "1.0"
-curv = { git = "https://github.com/KZen-networks/curv" , tag = "v0.2.3", features =  ["ec_secp256k1","merkle"]}
+curv = { git = "https://github.com/KZen-networks/curv" , tag = "v0.2.4", features =  ["ec_secp256k1","merkle"]}
 
 [dependencies.centipede]
 git = "https://github.com/KZen-networks/centipede"
-tag = "v0.2.2"
+tag = "v0.2.3"
 
 [dev-dependencies]
 hex = "0.3.2"

src/protocols/thresholdsig/bitcoin_schnorr.rs

@@ -176,20 +176,25 @@ pub struct LocalSig {
 impl LocalSig {
     pub fn compute(
         message: &[u8],
-        local_ephemaral_key: &SharedKeys,
+        local_ephemeral_key: &SharedKeys,
         local_private_key: &SharedKeys,
     ) -> LocalSig {
-        let beta_i = local_ephemaral_key.x_i.clone();
+        let beta_i = local_ephemeral_key.x_i.clone();
         let alpha_i = local_private_key.x_i.clone();
 
-        let e_bn = HSha256::create_hash(&[
-            &local_ephemaral_key.y.bytes_compressed_to_big_int(),
-            &local_private_key.y.bytes_compressed_to_big_int(),
-            &BigInt::from(message),
-        ]);
+        let message_len_bits = message.len() * 8;
+        let R = local_ephemeral_key.y.bytes_compressed_to_big_int();
+        let X = local_private_key.y.bytes_compressed_to_big_int();
+        let X_vec = BigInt::to_vec(&X);
+        let X_vec_len_bits = X_vec.len() * 8;
+        let e_bn = HSha256::create_hash_from_slice(
+            &BigInt::to_vec(
+                &((((R << X_vec_len_bits) + X) << message_len_bits) + BigInt::from(message)),
+            )[..],
+        );
+
         let e: FE = ECScalar::from(&e_bn);
         let gamma_i = beta_i + e.clone() * alpha_i;
-        //   let gamma_i = e.clone() * alpha_i ;
 
         LocalSig { gamma_i, e }
     }