Struct Ext 

pub struct Ext {
    pub x: Fp,
    pub y: Fp,
    pub z: Fp,
    pub t: Fp,
}

Extended twisted-Edwards point (X:Y:Z:T).

Affine x = X/Z, y = Y/Z, on -x^2 + y^2 = 1 + d x^2 y^2.

Fields

x: Fp

X.

y: Fp

Y.

z: Fp

Z.

t: Fp

T = XY/Z.

Implementations

impl Ext

pub fn neg(self) -> Ext

Negated point (-X:Y:Z:-T).

pub fn identity() -> Self

Identity (0:1:1:0).

pub fn basepoint() -> Self

Ed25519 basepoint: y = 4/5, x non-negative (even).

pub fn add(self, o: Ext) -> Ext

Complete unified addition (Hisil et al., a = -1).

Complete means it is correct for every pair of inputs, including doubling and the identity, which keeps this reference model simple.

pub fn double(self) -> Ext

Doubling, through the complete addition.

pub fn affine(self) -> (Fp, Fp)

Affine coordinates (X/Z, Y/Z).

pub fn compress(self) -> [u8; 32]

Standard 32-byte compressed encoding: y little endian with the sign of x in bit 255.

pub fn niels(self) -> Niels

Affine Niels form.

pub fn mul_bytes(self, k: &[u8; 32]) -> Ext

Scalar multiplication by a little-endian 256-bit integer (host only).

Double-and-add from the top bit, not constant time.

Trait Implementations

impl Clone for Ext

fn clone(&self) -> Ext

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Ext

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

Formats the value using the given formatter.

impl PartialEq for Ext

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

Tests for self and other values to be equal, and is used by ==.

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

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Copy for Ext

impl Eq for Ext

impl StructuralPartialEq for Ext