Struct ProjectivePoint 

pub struct ProjectivePoint { /* private fields */ }

A point on the SM2 curve in projective coordinates (X:Y:Z).

The point at infinity is represented as (0:1:0).

Implementations

impl ProjectivePoint

pub const fn identity() -> Self

The point at infinity (0 : 1 : 0).

pub const fn generator() -> Self

The curve generator G.

pub fn is_identity(&self) -> Choice

Whether this is the point at infinity (Z = 0). Constant-time.

pub fn add(&self, other: &Self) -> Self

Add two points using RCB Algorithm 4 (a=-3 specialized, complete).

Transcribed from eprint 2015/1060 Algorithm 4.

pub fn double(&self) -> Self

Double a point using RCB Algorithm 6 (a=-3 specialized). Cost: 3S + 5M + a few additions.

Transcribed from eprint 2015/1060 Algorithm 6.

pub fn neg(&self) -> Self

Negate a point: (X:Y:Z) -> (X:-Y:Z).

pub fn to_affine(&self) -> Option<(Fp, Fp)>

Convert to affine (x, y) coordinates. Returns None for the identity point (where Z = 0).

Constant-time caveat

The Z-inverse goes through crypto-bigint = 0.6’s ConstMontyForm::invert (safegcd / Bernstein-Yang), which is documented as constant-time but direct measurement on the project’s dudect harness shows |tau| ≈ 0.70 between different inputs. Callers that pass secret-derived Z (notably mul_g(k) inside the SM2 sign retry loop, where k is the secret nonce) inherit a measurable timing side-channel until v0.2 replaces the invert site with a Fermat-style pow_bounded_exp. See SECURITY.md for the full posture.

Trait Implementations

impl Clone for ProjectivePoint

fn clone(&self) -> ProjectivePoint

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl ConditionallySelectable for ProjectivePoint

fn conditional_select(a: &Self, b: &Self, choice: Choice) -> Self

Select a or b according to choice.

fn conditional_assign(&mut self, other: &Self, choice: Choice)

Conditionally assign other to self, according to choice.

fn conditional_swap(a: &mut Self, b: &mut Self, choice: Choice)

Conditionally swap self and other if choice == 1; otherwise, reassign both unto themselves.

impl ConstantTimeEq for ProjectivePoint

fn ct_eq(&self, other: &Self) -> Choice

Determine if two items are equal.

fn ct_ne(&self, other: &Self) -> Choice

Determine if two items are NOT equal.

impl Debug for ProjectivePoint

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl From<ProjectivePoint> for Sm2PublicKey

fn from(p: ProjectivePoint) -> Self

Converts to this type from the input type.

impl Copy for ProjectivePoint