Make it to compute e without converting through BigInt

ZenGo-X · Feb 17, 2020 · 180ad2f · 180ad2f
1 parent 5f520c0
commit 180ad2f
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Showing 2 changed files with 16 additions and 22 deletions.
diff --git a/src/protocols/thresholdsig/bitcoin_schnorr.rs b/src/protocols/thresholdsig/bitcoin_schnorr.rs
@@ -284,16 +284,15 @@ impl Signature {
 
 /// Compute e = h(V || Y || message)
 fn compute_e(v: &GE, y: &GE, message: &[u8]) -> FE {
- let message_len_bits = message.len() * 8;
- let R = v.bytes_compressed_to_big_int();
- let X = 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 v = v.get_element().serialize();
+ let y = y.get_element().serialize();
+
+ let mut vec: Vec<u8> = Vec::with_capacity(v.len() + y.len() + message.len());
+ vec.extend(&v[..]);
+ vec.extend(&y[..]);
+ vec.extend(message);
+
+ let e_bn = HSha256::create_hash_from_slice(&vec[..]);
  ECScalar::from(&e_bn)
 }
 

diff --git a/src/protocols/thresholdsig/zilliqa_schnorr.rs b/src/protocols/thresholdsig/zilliqa_schnorr.rs
@@ -353,20 +353,15 @@ impl Signature {
 
 /// Compute e = h(V || Y || message)
 fn compute_e(v: &GE, y: &GE, message: &[u8]) -> FE {
- let v_bn = v.bytes_compressed_to_big_int();
- let y_bn = y.bytes_compressed_to_big_int();
+ let v = v.get_element().serialize();
+ let y = y.get_element().serialize();
 
- let mut big_ints = vec![&v_bn, &y_bn];
+ let mut vec: Vec<u8> = Vec::with_capacity(v.len() + y.len() + message.len());
+ vec.extend(&v[..]);
+ vec.extend(&y[..]);
+ vec.extend(message);
 
- let m: Vec<BigInt> = Vec::from(message)
- .into_iter()
- .map(|i| BigInt::from(i as i32))
- .collect();
- for i in &m {
- big_ints.push(i);
- }
-
- let e_bn = HSha256::create_hash(&big_ints);
+ let e_bn = HSha256::create_hash_from_slice(&vec[..]);
  ECScalar::from(&e_bn)
 }