some clean up in the nist field methods

Signed-off-by: bytemare <[email protected]>

internal/field/field.go

@@ -15,11 +15,6 @@ import (
 	"math/big"
 )
 
-var (
-	zero = big.NewInt(0)
-	one  = big.NewInt(1)
-)
-
 // String2Int returns a big.Int representation of the integer s.
 func String2Int(s string) big.Int {
 	if p, _ := new(big.Int).SetString(s, 0); p != nil {
@@ -63,16 +58,6 @@ func NewField(prime *big.Int) Field {
 	}
 }
 
-// Zero returns the zero big.Int of the finite Field.
-func (f Field) Zero() *big.Int {
-	return zero
-}
-
-// One returns one big.Int of the finite Field.
-func (f Field) One() *big.Int {
-	return one
-}
-
 // Random sets res to a random big.Int in the Field.
 func (f Field) Random(res *big.Int) *big.Int {
 	tmp, err := rand.Int(rand.Reader, f.order)
@@ -96,11 +81,6 @@ func (f Field) ByteLen() int {
 	return f.byteLen
 }
 
-// AreEqual returns whether both elements are equal.
-func (f Field) AreEqual(f1, f2 *big.Int) bool {
-	return f.IsZero(f.Sub(&big.Int{}, f1, f2))
-}
-
 // IsZero returns whether the big.Int is equivalent to zero.
 func (f Field) IsZero(e *big.Int) bool {
 	return e.Sign() == 0

internal/nist/scalar.go

@@ -30,7 +30,6 @@ func newScalar(f *field.Field) *Scalar {
 		field:  f,
 		scalar: big.Int{},
 	}
-	s.scalar.Set(s.field.Zero())
 
 	return s
 }
@@ -64,13 +63,13 @@ func (s *Scalar) Group() byte {
 
 // Zero sets s to 0, and returns it.
 func (s *Scalar) Zero() internal.Scalar {
-	s.scalar.Set(s.field.Zero())
+	s.scalar.Set(big.NewInt(0))
 	return s
 }
 
 // One sets s to 1, and returns it.
 func (s *Scalar) One() internal.Scalar {
-	s.scalar.Set(s.field.One())
+	s.scalar.Set(big.NewInt(1))
 	return s
 }
 
@@ -182,7 +181,7 @@ func (s *Scalar) LessOrEqual(scalar internal.Scalar) int {
 
 // IsZero returns whether the scalar is 0.
 func (s *Scalar) IsZero() bool {
-	return s.field.AreEqual(&s.scalar, s.field.Zero())
+	return s.field.IsZero(&s.scalar)
 }
 
 // Set sets the receiver to the value of the argument scalar, and returns the receiver.