Implement TryFrom<Scalar/Projective/AffinePoint> for NonIdentity/ZeroScalar

bign256/src/arithmetic/scalar.rs

@@ -223,6 +223,15 @@ impl From<&SecretKey> for Scalar {
     }
 }
 
+/// The constant-time alternative is available at [`NonZeroScalar::new()`].
+impl TryFrom<Scalar> for NonZeroScalar {
+    type Error = Error;
+
+    fn try_from(scalar: Scalar) -> Result<Self> {
+        NonZeroScalar::new(scalar).into_option().ok_or(Error)
+    }
+}
+
 impl TryFrom<U256> for Scalar {
     type Error = Error;
 

bp256/src/r1/arithmetic.rs

@@ -2,7 +2,7 @@
 
 use super::BrainpoolP256r1;
 use crate::{FieldElement, Scalar};
-use elliptic_curve::{CurveArithmetic, PrimeCurveArithmetic};
+use elliptic_curve::{CurveArithmetic, Error, PrimeCurveArithmetic};
 use primeorder::{PrimeCurveParams, point_arithmetic};
 
 /// Elliptic curve point in affine coordinates.
@@ -76,3 +76,12 @@ impl From<&Scalar> for ScalarPrimitive {
         ScalarPrimitive::new(scalar.into()).unwrap()
     }
 }
+
+/// The constant-time alternative is available at [`NonZeroScalar::new()`].
+impl TryFrom<Scalar> for NonZeroScalar {
+    type Error = Error;
+
+    fn try_from(scalar: Scalar) -> Result<Self, Error> {
+        NonZeroScalar::new(scalar).into_option().ok_or(Error)
+    }
+}

bp256/src/t1/arithmetic.rs

@@ -2,7 +2,7 @@
 
 use super::BrainpoolP256t1;
 use crate::{FieldElement, Scalar};
-use elliptic_curve::{CurveArithmetic, PrimeCurveArithmetic};
+use elliptic_curve::{CurveArithmetic, Error, PrimeCurveArithmetic};
 use primeorder::{PrimeCurveParams, point_arithmetic};
 
 /// Elliptic curve point in affine coordinates.
@@ -76,3 +76,12 @@ impl From<&Scalar> for ScalarPrimitive {
         ScalarPrimitive::new(scalar.into()).unwrap()
     }
 }
+
+/// The constant-time alternative is available at [`NonZeroScalar::new()`].
+impl TryFrom<Scalar> for NonZeroScalar {
+    type Error = Error;
+
+    fn try_from(scalar: Scalar) -> Result<Self, Error> {
+        NonZeroScalar::new(scalar).into_option().ok_or(Error)
+    }
+}

bp384/src/r1/arithmetic.rs

@@ -2,7 +2,7 @@
 
 use super::BrainpoolP384r1;
 use crate::{FieldElement, Scalar};
-use elliptic_curve::{CurveArithmetic, PrimeCurveArithmetic};
+use elliptic_curve::{CurveArithmetic, Error, PrimeCurveArithmetic};
 use primeorder::{PrimeCurveParams, point_arithmetic};
 
 /// Elliptic curve point in affine coordinates.
@@ -82,3 +82,12 @@ impl From<&Scalar> for ScalarPrimitive {
         ScalarPrimitive::new(scalar.into()).unwrap()
     }
 }
+
+/// The constant-time alternative is available at [`NonZeroScalar::new()`].
+impl TryFrom<Scalar> for NonZeroScalar {
+    type Error = Error;
+
+    fn try_from(scalar: Scalar) -> Result<Self, Error> {
+        NonZeroScalar::new(scalar).into_option().ok_or(Error)
+    }
+}

bp384/src/t1/arithmetic.rs

@@ -2,7 +2,7 @@
 
 use super::BrainpoolP384t1;
 use crate::{FieldElement, Scalar};
-use elliptic_curve::{CurveArithmetic, PrimeCurveArithmetic};
+use elliptic_curve::{CurveArithmetic, Error, PrimeCurveArithmetic};
 use primeorder::{PrimeCurveParams, point_arithmetic};
 
 /// Elliptic curve point in affine coordinates.
@@ -82,3 +82,12 @@ impl From<&Scalar> for ScalarPrimitive {
         ScalarPrimitive::new(scalar.into()).unwrap()
     }
 }
+
+/// The constant-time alternative is available at [`NonZeroScalar::new()`].
+impl TryFrom<Scalar> for NonZeroScalar {
+    type Error = Error;
+
+    fn try_from(scalar: Scalar) -> Result<Self, Error> {
+        NonZeroScalar::new(scalar).into_option().ok_or(Error)
+    }
+}

k256/src/arithmetic/affine.rs

@@ -329,6 +329,15 @@ impl From<&PublicKey> for AffinePoint {
     }
 }
 
+/// The constant-time alternative is available at [`NonIdentity::new()`].
+impl TryFrom<AffinePoint> for NonIdentity<AffinePoint> {
+    type Error = Error;
+
+    fn try_from(affine_point: AffinePoint) -> Result<Self> {
+        NonIdentity::new(affine_point).into_option().ok_or(Error)
+    }
+}
+
 impl TryFrom<AffinePoint> for PublicKey {
     type Error = Error;
 

k256/src/arithmetic/projective.rs

@@ -664,6 +664,15 @@ impl From<&PublicKey> for ProjectivePoint {
     }
 }
 
+/// The constant-time alternative is available at [`NonIdentity::new()`].
+impl TryFrom<ProjectivePoint> for NonIdentity<ProjectivePoint> {
+    type Error = Error;
+
+    fn try_from(point: ProjectivePoint) -> Result<Self> {
+        NonIdentity::new(point).into_option().ok_or(Error)
+    }
+}
+
 impl TryFrom<ProjectivePoint> for PublicKey {
     type Error = Error;
 

k256/src/arithmetic/scalar.rs

@@ -12,7 +12,7 @@ use core::{
     ops::{Add, AddAssign, Mul, MulAssign, Neg, Shr, ShrAssign, Sub, SubAssign},
 };
 use elliptic_curve::{
-    Curve, ScalarPrimitive,
+    Curve, Error, ScalarPrimitive,
     bigint::{Limb, U256, U512, Word, prelude::*},
     ff::{self, Field, PrimeField},
     ops::{Invert, Reduce, ReduceNonZero},
@@ -413,6 +413,15 @@ impl From<&Scalar> for ScalarPrimitive<Secp256k1> {
     }
 }
 
+/// The constant-time alternative is available at [`NonZeroScalar::new()`].
+impl TryFrom<Scalar> for NonZeroScalar {
+    type Error = Error;
+
+    fn try_from(scalar: Scalar) -> Result<Self, Error> {
+        NonZeroScalar::new(scalar).into_option().ok_or(Error)
+    }
+}
+
 impl FromUintUnchecked for Scalar {
     type Uint = U256;
 

p192/src/arithmetic/scalar.rs

@@ -253,6 +253,15 @@ impl From<&Scalar> for ScalarPrimitive<NistP192> {
     }
 }
 
+/// The constant-time alternative is available at [`NonZeroScalar::new()`].
+impl TryFrom<Scalar> for NonZeroScalar {
+    type Error = Error;
+
+    fn try_from(scalar: Scalar) -> Result<Self> {
+        NonZeroScalar::new(scalar).into_option().ok_or(Error)
+    }
+}
+
 impl TryFrom<U192> for Scalar {
     type Error = Error;
 

p224/src/arithmetic/scalar.rs

@@ -254,6 +254,15 @@ impl From<&SecretKey> for Scalar {
     }
 }
 
+/// The constant-time alternative is available at [`NonZeroScalar::new()`].
+impl TryFrom<Scalar> for NonZeroScalar {
+    type Error = Error;
+
+    fn try_from(scalar: Scalar) -> Result<Self> {
+        NonZeroScalar::new(scalar).into_option().ok_or(Error)
+    }
+}
+
 impl TryFrom<Uint> for Scalar {
     type Error = Error;
 

p256/src/arithmetic/scalar.rs

@@ -12,7 +12,7 @@ use core::{
     ops::{Add, AddAssign, Mul, MulAssign, Neg, Shr, ShrAssign, Sub, SubAssign},
 };
 use elliptic_curve::{
-    Curve, ScalarPrimitive,
+    Curve, Error, ScalarPrimitive,
     bigint::{Limb, U256, prelude::*},
     group::ff::{self, Field, PrimeField},
     ops::{Invert, Reduce, ReduceNonZero},
@@ -533,6 +533,15 @@ impl From<&Scalar> for ScalarBits {
     }
 }
 
+/// The constant-time alternative is available at [`NonZeroScalar::new()`].
+impl TryFrom<Scalar> for NonZeroScalar {
+    type Error = Error;
+
+    fn try_from(scalar: Scalar) -> Result<Self, Error> {
+        NonZeroScalar::new(scalar).into_option().ok_or(Error)
+    }
+}
+
 impl Add<Scalar> for Scalar {
     type Output = Scalar;
 

p384/src/arithmetic/scalar.rs

@@ -292,6 +292,15 @@ impl From<&SecretKey> for Scalar {
     }
 }
 
+/// The constant-time alternative is available at [`NonZeroScalar::new()`].
+impl TryFrom<Scalar> for NonZeroScalar {
+    type Error = Error;
+
+    fn try_from(scalar: Scalar) -> Result<Self> {
+        NonZeroScalar::new(scalar).into_option().ok_or(Error)
+    }
+}
+
 impl TryFrom<U384> for Scalar {
     type Error = Error;
 

p521/src/arithmetic/scalar.rs

@@ -698,6 +698,15 @@ impl From<&SecretKey> for Scalar {
     }
 }
 
+/// The constant-time alternative is available at [`NonZeroScalar::new()`].
+impl TryFrom<Scalar> for NonZeroScalar {
+    type Error = Error;
+
+    fn try_from(scalar: Scalar) -> Result<Self> {
+        NonZeroScalar::new(scalar).into_option().ok_or(Error)
+    }
+}
+
 impl TryFrom<U576> for Scalar {
     type Error = Error;
 

primeorder/src/affine.rs

@@ -367,6 +367,18 @@ where
     }
 }
 
+/// The constant-time alternative is available at [`NonIdentity::new()`].
+impl<C> TryFrom<AffinePoint<C>> for NonIdentity<AffinePoint<C>>
+where
+    C: PrimeCurveParams,
+{
+    type Error = Error;
+
+    fn try_from(affine_point: AffinePoint<C>) -> Result<Self> {
+        NonIdentity::new(affine_point).into_option().ok_or(Error)
+    }
+}
+
 impl<C> TryFrom<EncodedPoint<C>> for AffinePoint<C>
 where
     C: PrimeCurveParams,

primeorder/src/projective.rs

@@ -477,6 +477,18 @@ where
     }
 }
 
+/// The constant-time alternative is available at [`NonIdentity::new()`].
+impl<C> TryFrom<ProjectivePoint<C>> for NonIdentity<ProjectivePoint<C>>
+where
+    C: PrimeCurveParams,
+{
+    type Error = Error;
+
+    fn try_from(point: ProjectivePoint<C>) -> Result<Self> {
+        NonIdentity::new(point).into_option().ok_or(Error)
+    }
+}
+
 impl<C> TryFrom<ProjectivePoint<C>> for PublicKey<C>
 where
     C: PrimeCurveParams,

sm2/src/arithmetic/scalar.rs

@@ -238,6 +238,15 @@ impl From<&SecretKey> for Scalar {
     }
 }
 
+/// The constant-time alternative is available at [`NonZeroScalar::new()`].
+impl TryFrom<Scalar> for NonZeroScalar {
+    type Error = Error;
+
+    fn try_from(scalar: Scalar) -> Result<Self> {
+        NonZeroScalar::new(scalar).into_option().ok_or(Error)
+    }
+}
+
 impl TryFrom<U256> for Scalar {
     type Error = Error;