Move normalize() into is_odd()

Author: daxpedda

k256/src/arithmetic/affine.rs

@@ -154,7 +154,7 @@ impl DecompressPoint<Secp256k1> for AffinePoint {
                 let y = FieldElement::conditional_select(
                     &beta.negate(1),
                     &beta,
-                    beta.normalize().is_odd().ct_eq(&y_is_odd),
+                    beta.is_odd().ct_eq(&y_is_odd),
                 );
 
                 Self {

k256/src/arithmetic/field/field_impl.rs

@@ -89,8 +89,7 @@ impl FieldElementImpl {
     }
 
     pub fn is_odd(&self) -> Choice {
-        debug_assert!(self.normalized);
-        self.value.is_odd()
+        self.normalize().value.is_odd()
     }
 
     pub fn negate(&self, magnitude: u32) -> Self {

k256/src/arithmetic/hash2curve.rs

@@ -126,7 +126,7 @@ impl OsswuMap for FieldElement {
         // if e2, y = y1, else y = y2
         let mut y = Self::conditional_select(&y2, &y1, e2);
 
-        y.conditional_assign(&-y, self.normalize().sgn0() ^ y.normalize().sgn0());
+        y.conditional_assign(&-y, self.sgn0() ^ y.sgn0());
         (x, y)
     }
 }

k256/src/ecdsa/sign.rs

@@ -183,7 +183,7 @@ impl SignPrimitive<Secp256k1> for Scalar {
         }
 
         let signature = Signature::from_scalars(r, s)?;
-        let is_r_odd: bool = R.y.normalize().is_odd().into();
+        let is_r_odd: bool = R.y.is_odd().into();
         let is_s_high: bool = signature.s().is_high().into();
         let signature_low = signature.normalize_s().unwrap_or(signature);
         let recovery_id = ecdsa_core::RecoveryId::new(is_r_odd ^ is_s_high, false);