pub trait CurveExt:
PrimeCurve<Affine = Self::AffineExt, Scalar = Self::ScalarExt>
+ Group
+ Default
+ ConditionallySelectable
+ ConstantTimeEq
+ From<Self::Affine> {
type ScalarExt: WithSmallOrderMulGroup<3>;
type Base: WithSmallOrderMulGroup<3>;
type AffineExt: CurveAffine<CurveExt = Self, ScalarExt = Self::ScalarExt, Output = Self, Output = Self> + Mul<Self::ScalarExt> + for<'r> Mul<Self::ScalarExt>;
const CURVE_ID: &'static str;
// Required methods
fn endo(&self) -> Self;
fn jacobian_coordinates(&self) -> (Self::Base, Self::Base, Self::Base);
fn hash_to_curve<'a>(
domain_prefix: &'a str,
) -> Box<dyn Fn(&[u8]) -> Self + 'a>;
fn is_on_curve(&self) -> Choice;
fn a() -> Self::Base;
fn b() -> Self::Base;
fn new_jacobian(
x: Self::Base,
y: Self::Base,
z: Self::Base,
) -> CtOption<Self>;
}Expand description
This trait is a common interface for dealing with elements of an elliptic curve group in a “projective” form, where that arithmetic is usually more efficient.
Requires the alloc feature flag because of hash_to_curve.
Required Associated Constants§
Required Associated Types§
Sourcetype ScalarExt: WithSmallOrderMulGroup<3>
type ScalarExt: WithSmallOrderMulGroup<3>
The scalar field of this elliptic curve.
Sourcetype Base: WithSmallOrderMulGroup<3>
type Base: WithSmallOrderMulGroup<3>
The base field over which this elliptic curve is constructed.
Required Methods§
Sourcefn endo(&self) -> Self
fn endo(&self) -> Self
Apply the curve endomorphism by multiplying the x-coordinate by an element of multiplicative order 3.
Sourcefn jacobian_coordinates(&self) -> (Self::Base, Self::Base, Self::Base)
fn jacobian_coordinates(&self) -> (Self::Base, Self::Base, Self::Base)
Return the Jacobian coordinates of this point.
Sourcefn hash_to_curve<'a>(domain_prefix: &'a str) -> Box<dyn Fn(&[u8]) -> Self + 'a>
fn hash_to_curve<'a>(domain_prefix: &'a str) -> Box<dyn Fn(&[u8]) -> Self + 'a>
Requests a hasher that accepts messages and returns near-uniformly
distributed elements in the group, given domain prefix domain_prefix.
This method is suitable for use as a random oracle.
§Example
use pasta_curves::arithmetic::CurveExt;
fn pedersen_commitment<C: CurveExt>(
x: C::ScalarExt,
r: C::ScalarExt,
) -> C::Affine {
let hasher = C::hash_to_curve("z.cash:example_pedersen_commitment");
let g = hasher(b"g");
let h = hasher(b"h");
(g * x + &(h * r)).to_affine()
}Sourcefn is_on_curve(&self) -> Choice
fn is_on_curve(&self) -> Choice
Returns whether or not this element is on the curve; should always be true unless an “unchecked” API was used.
Dyn Compatibility§
This trait is not dyn compatible.
In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.