Trait CurveSpec 

pub trait CurveSpec: Sized + 'static {
    type BaseField: UintSpec;
    type ScalarField: UintSpec;

    const ID: Felt;
    const GENERATOR_X: Limbs;
    const GENERATOR_Y: Limbs;

    // Required methods
    fn point_from_affine(
        x: Limbs,
        y: Limbs,
    ) -> Result<CurvePoint, PrecompileError>;
    fn add(
        lhs: CurvePoint,
        rhs: CurvePoint,
    ) -> Result<CurvePoint, PrecompileError>;
    fn neg(point: CurvePoint) -> Result<CurvePoint, PrecompileError>;

    // Provided methods
    fn generator() -> CurvePoint { ... }
    fn canonical_point(point: CurvePoint) -> Result<CurvePoint, PrecompileError> { ... }
    fn is_on_curve(point: &CurvePoint) -> bool { ... }
    fn sub(
        lhs: CurvePoint,
        rhs: CurvePoint,
    ) -> Result<CurvePoint, PrecompileError> { ... }
    fn mul_scalar(
        point: CurvePoint,
        scalar: Limbs,
    ) -> Result<CurvePoint, PrecompileError> { ... }
}

Spec for one fixed curve.

This trait intentionally describes only the affine encoding and group operations needed by the precompile dispatcher. It is curve-model-generic, not short-Weierstrass-specific; curve-model-specific equations, coefficients, and formulas live behind narrower extension traits such as ShortWeierstrassSpec.

Trust contract:

• Self::point_from_affine and Self::canonical_point are checked boundary helpers. They validate and canonicalize raw affine coordinates before a CurvePoint becomes trusted.
• Self::add, Self::neg, Self::sub, and Self::mul_scalar are trusted internal operations. Their point inputs must already be canonical valid points obtained from checked boundaries, canonical curve VALUE nodes, or previous curve operations.
• Violating these preconditions is not memory-unsafe, but formulas may return invalid or nonsensical arithmetic results, or fail with InvalidPayload.

Required Associated Constants

const ID: Felt

Stable local curve selector used by host-side metadata.

Deferred curve VALUE tags carry fixed VM-owned group pointers, while operation tags use zero immediates.

const GENERATOR_X: Limbs

Conventional generator x-coordinate, little-endian u32 limbs.

const GENERATOR_Y: Limbs

Conventional generator y-coordinate, little-endian u32 limbs.

Required Associated Types

type BaseField: UintSpec

Base field used by affine point coordinates.

type ScalarField: UintSpec

Scalar field associated with this curve.

Required Methods

fn point_from_affine(x: Limbs, y: Limbs) -> Result<CurvePoint, PrecompileError>

Checked boundary helper that constructs this curve’s canonical point from affine coordinates.

This is where raw affine limbs become a trusted CurvePoint. Implementations must validate that x and y are canonical base-field elements and satisfy the curve equation. They should also canonicalize any model-specific identity representation to CurvePoint::Identity before the point is re-encoded as a graph VALUE node.

fn add(lhs: CurvePoint, rhs: CurvePoint) -> Result<CurvePoint, PrecompileError>

Trusted internal operation that adds two canonical valid points on this curve.

Preconditions: both operands must have come from Self::point_from_affine, Self::canonical_point, a canonical curve VALUE node, or previous curve operations. Release builds do not revalidate arbitrary coordinates before applying the curve formula. Violating this contract is not memory-unsafe, but may produce invalid or nonsensical results, or fail with InvalidPayload.

fn neg(point: CurvePoint) -> Result<CurvePoint, PrecompileError>

Trusted internal operation that negates a canonical valid point on this curve.

Precondition: point must have come from Self::point_from_affine, Self::canonical_point, a canonical curve VALUE node, or previous curve operations. Release builds do not revalidate arbitrary coordinates before applying the curve formula. Violating this contract is not memory-unsafe, but may produce invalid or nonsensical results, or fail with InvalidPayload.

Provided Methods

fn generator() -> CurvePoint

Returns this curve’s conventional generator point.

fn canonical_point(point: CurvePoint) -> Result<CurvePoint, PrecompileError>

Checked boundary helper that returns the canonical representation of point.

Affine inputs are revalidated through Self::point_from_affine; identity is accepted as the already-canonical identity. Arithmetic methods below assume their inputs already came from checked graph nodes or previous curve operations.

fn is_on_curve(point: &CurvePoint) -> bool

Returns whether point is a valid point on this curve.

fn sub(lhs: CurvePoint, rhs: CurvePoint) -> Result<CurvePoint, PrecompileError>

Trusted internal operation that subtracts two canonical valid points on this curve.

Preconditions are the same as Self::add and Self::neg: operands must already be canonical valid points from checked boundaries, canonical curve VALUE nodes, or previous curve operations. Violating this contract is not memory-unsafe, but may produce invalid or nonsensical results, or fail with InvalidPayload.

fn mul_scalar( point: CurvePoint, scalar: Limbs, ) -> Result<CurvePoint, PrecompileError>

Trusted internal operation that multiplies a canonical valid point by a canonical scalar.

Precondition: point must already be a canonical valid point from a checked boundary, canonical curve VALUE node, or previous curve operation. scalar must be canonical in this curve’s scalar field. Violating the point precondition is not memory-unsafe, but may produce invalid or nonsensical results, or fail with InvalidPayload.

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety".

Implementors