Struct Point 

pub struct Point(/* private fields */);

A point on the curve, the point at infinity included.

Held in the arithmetic driver’s own representation (projective coordinates, typically), so a chain of operations converts to affine coordinates once, when asked to through Self::to_affine. Comparing two points converts both. Arithmetic is served by the curve’s arithmetic driver.

Implementations

impl Point

pub fn generator() -> Self

The base point G.

pub fn identity() -> Self

The point at infinity.

pub fn from_xy(x: &[u8; 32], y: &[u8; 32]) -> Result<Self, Error>

Build a point from its coordinates, checking that it is on the curve.

pub fn from_sec1(bytes: &[u8; 65]) -> Result<Self, Error>

Parse an uncompressed SEC1 encoding (0x04 || x || y), checking that the point is on the curve.

pub fn from_affine(p: &P256Point) -> Result<Self, Error>

Import an affine point, checking that it is on the curve.

pub fn to_affine(&self) -> Option<P256Point>

The affine coordinates, or None for the point at infinity.

pub fn to_sec1(&self) -> Option<[u8; 65]>

The uncompressed SEC1 encoding (0x04 || x || y), or None for the point at infinity.

pub fn is_identity(&self) -> bool

Whether this is the point at infinity.

pub fn from_driver(p: P256ArithImplPoint) -> Self

Wrap a point in the driver representation.

pub fn as_driver(&self) -> &P256ArithImplPoint

The driver representation.

pub fn neg(&self) -> Self

-self.

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

self + other.

pub fn mul(&self, k: &Scalar) -> Self

k * self.

pub fn mul_base(k: &Scalar) -> Self

k * G.

pub fn lincomb(a: &Scalar, p: &Self, b: &Scalar, q: &Self) -> Self

a * p + b * q.

Constant-time in the scalars: safe for secret scalars, as in a PAKE or a Schnorr-style signature. Cheaper than the equivalent muls and add when the driver shares the doublings.

pub fn lincomb_vartime(a: &Scalar, p: &Self, b: &Scalar, q: &Self) -> Self

a * p + b * q.

May be variable-time: only for public inputs, as in signature verification. Faster than Self::lincomb.

Trait Implementations

impl Clone for Point

fn clone(&self) -> Point

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for Point

impl Debug for Point

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

Formats the value using the given formatter.

impl Eq for Point

impl Format for Point

Available on crate feature defmt only.

fn format(&self, f: Formatter<'_>)

Writes the defmt representation of self to fmt.

impl PartialEq for Point

fn eq(&self, other: &Self) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl TryFrom<Point> for P256Point

fn try_from(p: Point) -> Result<Self, Error>

Fails for the point at infinity.

type Error = Error

The type returned in the event of a conversion error.

impl TryFrom<Point> for PublicKey

fn try_from(p: Point) -> Result<Self, Error>

Fails for the point at infinity.

type Error = Error

The type returned in the event of a conversion error.

impl TryFrom<Point> for VerifyingKey

fn try_from(p: Point) -> Result<Self, Error>

Fails for the point at infinity.

type Error = Error

The type returned in the event of a conversion error.

impl TryFrom<PublicKey> for Point

type Error = Error

The type returned in the event of a conversion error.

fn try_from(p: PublicKey) -> Result<Self, Error>

Performs the conversion.

impl TryFrom<VerifyingKey> for Point

type Error = Error

The type returned in the event of a conversion error.

fn try_from(p: VerifyingKey) -> Result<Self, Error>

Performs the conversion.