chore: checkpoint before Python removal

vendor/group/src/prime.rs

@@ -0,0 +1,50 @@
+use core::fmt;
+use core::ops::{Mul, Neg};
+use ff::PrimeField;
+use subtle::Choice;
+
+use crate::{Curve, Group, GroupEncoding};
+
+/// This trait represents an element of a prime-order cryptographic group.
+pub trait PrimeGroup: Group + GroupEncoding {}
+
+/// Efficient representation of an elliptic curve point guaranteed to be
+/// in the correct prime order subgroup.
+pub trait PrimeCurve: Curve<AffineRepr = <Self as PrimeCurve>::Affine> + PrimeGroup {
+    type Affine: PrimeCurveAffine<Curve = Self, Scalar = Self::Scalar>
+        + Mul<Self::Scalar, Output = Self>
+        + for<'r> Mul<&'r Self::Scalar, Output = Self>;
+}
+
+/// Affine representation of an elliptic curve point guaranteed to be
+/// in the correct prime order subgroup.
+pub trait PrimeCurveAffine: GroupEncoding
+    + Copy
+    + Clone
+    + Sized
+    + Send
+    + Sync
+    + fmt::Debug
+    + PartialEq
+    + Eq
+    + 'static
+    + Neg<Output = Self>
+    + Mul<<Self as PrimeCurveAffine>::Scalar, Output = <Self as PrimeCurveAffine>::Curve>
+    + for<'r> Mul<&'r <Self as PrimeCurveAffine>::Scalar, Output = <Self as PrimeCurveAffine>::Curve>
+{
+    type Scalar: PrimeField;
+    type Curve: PrimeCurve<Affine = Self, Scalar = Self::Scalar>;
+
+    /// Returns the additive identity.
+    fn identity() -> Self;
+
+    /// Returns a fixed generator of unknown exponent.
+    fn generator() -> Self;
+
+    /// Determines if this point represents the point at infinity; the
+    /// additive identity.
+    fn is_identity(&self) -> Choice;
+
+    /// Converts this element to its curve representation.
+    fn to_curve(&self) -> Self::Curve;
+}