Struct curve25519_dalek::edwards::EdwardsPoint

pub struct EdwardsPoint { /* fields omitted */ }

An EdwardsPoint represents a point on the Edwards form of Curve25519.

Methods

impl EdwardsPoint

fn to_montgomery(&self) -> MontgomeryPoint

Convert this EdwardsPoint on the Edwards model to the corresponding MontgomeryPoint on the Montgomery model.

Note that this is a one-way conversion, since the Montgomery model does not retain sign information.

fn compress(&self) -> CompressedEdwardsY

Compress this point to CompressedEdwardsY format.

impl EdwardsPoint

fn mult_by_cofactor(&self) -> EdwardsPoint

Multiply by the cofactor: return \([8]P\).

fn is_small_order(&self) -> bool

Determine if this point is of small order.

Return

• true if self is in the torsion subgroup \( \mathcal E[8] \);
• false if self is not in the torsion subgroup \( \mathcal E[8] \).

Example

use curve25519_dalek::constants;

// Generator of the prime-order subgroup
let P = constants::ED25519_BASEPOINT_POINT;
// Generator of the torsion subgroup
let Q = constants::EIGHT_TORSION[1];

// P has large order
assert_eq!(P.is_small_order(), false);

// Q has small order
assert_eq!(Q.is_small_order(), true);

fn is_torsion_free(&self) -> bool

Determine if this point is “torsion-free”, i.e., is contained in the prime-order subgroup.

Return

• true if self has zero torsion component and is in the prime-order subgroup;
• false if self has a nonzero torsion component and is not in the prime-order subgroup.

Example

use curve25519_dalek::constants;

// Generator of the prime-order subgroup
let P = constants::ED25519_BASEPOINT_POINT;
// Generator of the torsion subgroup
let Q = constants::EIGHT_TORSION[1];

// P is torsion-free
assert_eq!(P.is_torsion_free(), true);

// P + Q is not torsion-free
assert_eq!((P+Q).is_torsion_free(), false);

Trait Implementations

impl Copy for EdwardsPoint

impl Clone for EdwardsPoint

fn clone(&self) -> EdwardsPoint

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Identity for EdwardsPoint

fn identity() -> EdwardsPoint

Returns the identity element of the curve. Can be used as a constructor.

impl ConditionallyAssignable for EdwardsPoint

fn conditional_assign(&mut self, other: &EdwardsPoint, choice: u8)

Conditionally assign other to self in constant time.

impl Equal for EdwardsPoint

fn ct_eq(&self, other: &EdwardsPoint) -> u8

Determine if two items are equal in constant time.

impl PartialEq for EdwardsPoint

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

This method tests for self and other values to be equal, and is used by ==.

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

This method tests for !=.

impl Eq for EdwardsPoint

impl<'a, 'b> Add<&'b EdwardsPoint> for &'a EdwardsPoint

type Output = EdwardsPoint

The resulting type after applying the + operator.

fn add(self, other: &'b EdwardsPoint) -> EdwardsPoint

Performs the + operation.

impl<'b> Add<&'b EdwardsPoint> for EdwardsPoint

type Output = EdwardsPoint

The resulting type after applying the + operator.

fn add(self, rhs: &'b EdwardsPoint) -> EdwardsPoint

Performs the + operation.

impl<'a> Add<EdwardsPoint> for &'a EdwardsPoint

type Output = EdwardsPoint

The resulting type after applying the + operator.

fn add(self, rhs: EdwardsPoint) -> EdwardsPoint

Performs the + operation.

impl Add<EdwardsPoint> for EdwardsPoint

type Output = EdwardsPoint

The resulting type after applying the + operator.

fn add(self, rhs: EdwardsPoint) -> EdwardsPoint

Performs the + operation.

impl<'b> AddAssign<&'b EdwardsPoint> for EdwardsPoint

fn add_assign(&mut self, _rhs: &'b EdwardsPoint)

Performs the += operation.

impl AddAssign<EdwardsPoint> for EdwardsPoint

fn add_assign(&mut self, rhs: EdwardsPoint)

Performs the += operation.

impl<'a, 'b> Sub<&'b EdwardsPoint> for &'a EdwardsPoint

type Output = EdwardsPoint

The resulting type after applying the - operator.

fn sub(self, other: &'b EdwardsPoint) -> EdwardsPoint

Performs the - operation.

impl<'b> Sub<&'b EdwardsPoint> for EdwardsPoint

type Output = EdwardsPoint

The resulting type after applying the - operator.

fn sub(self, rhs: &'b EdwardsPoint) -> EdwardsPoint

Performs the - operation.

impl<'a> Sub<EdwardsPoint> for &'a EdwardsPoint

type Output = EdwardsPoint

The resulting type after applying the - operator.

fn sub(self, rhs: EdwardsPoint) -> EdwardsPoint

Performs the - operation.

impl Sub<EdwardsPoint> for EdwardsPoint

type Output = EdwardsPoint

The resulting type after applying the - operator.

fn sub(self, rhs: EdwardsPoint) -> EdwardsPoint

Performs the - operation.

impl<'b> SubAssign<&'b EdwardsPoint> for EdwardsPoint

fn sub_assign(&mut self, _rhs: &'b EdwardsPoint)

Performs the -= operation.

impl SubAssign<EdwardsPoint> for EdwardsPoint

fn sub_assign(&mut self, rhs: EdwardsPoint)

Performs the -= operation.

impl<'a> Neg for &'a EdwardsPoint

type Output = EdwardsPoint

The resulting type after applying the - operator.

fn neg(self) -> EdwardsPoint

Performs the unary - operation.

impl Neg for EdwardsPoint

type Output = EdwardsPoint

The resulting type after applying the - operator.

fn neg(self) -> EdwardsPoint

Performs the unary - operation.

impl<'b> MulAssign<&'b Scalar> for EdwardsPoint

fn mul_assign(&mut self, scalar: &'b Scalar)

Performs the *= operation.

impl MulAssign<Scalar> for EdwardsPoint

fn mul_assign(&mut self, rhs: Scalar)

Performs the *= operation.

impl<'b> Mul<&'b Scalar> for EdwardsPoint

type Output = EdwardsPoint

The resulting type after applying the * operator.

fn mul(self, rhs: &'b Scalar) -> EdwardsPoint

Performs the * operation.

impl<'a> Mul<Scalar> for &'a EdwardsPoint

type Output = EdwardsPoint

The resulting type after applying the * operator.

fn mul(self, rhs: Scalar) -> EdwardsPoint

Performs the * operation.

impl Mul<Scalar> for EdwardsPoint

type Output = EdwardsPoint

The resulting type after applying the * operator.

fn mul(self, rhs: Scalar) -> EdwardsPoint

Performs the * operation.

impl<'a, 'b> Mul<&'b Scalar> for &'a EdwardsPoint

type Output = EdwardsPoint

The resulting type after applying the * operator.

fn mul(self, scalar: &'b Scalar) -> EdwardsPoint

Scalar multiplication: compute scalar * self.

For scalar multiplication of a basepoint, EdwardsBasepointTable is approximately 4x faster.

impl Debug for EdwardsPoint

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

Formats the value using the given formatter.

impl<'a, 'b> Add<&'b ProjectiveNielsPoint> for &'a EdwardsPoint

type Output = CompletedPoint

The resulting type after applying the + operator.

fn add(self, other: &'b ProjectiveNielsPoint) -> CompletedPoint

Performs the + operation.

impl<'a, 'b> Sub<&'b ProjectiveNielsPoint> for &'a EdwardsPoint

type Output = CompletedPoint

The resulting type after applying the - operator.

fn sub(self, other: &'b ProjectiveNielsPoint) -> CompletedPoint

Performs the - operation.

impl<'a, 'b> Add<&'b AffineNielsPoint> for &'a EdwardsPoint

type Output = CompletedPoint

The resulting type after applying the + operator.

fn add(self, other: &'b AffineNielsPoint) -> CompletedPoint

Performs the + operation.

impl<'a, 'b> Sub<&'b AffineNielsPoint> for &'a EdwardsPoint

type Output = CompletedPoint

The resulting type after applying the - operator.

fn sub(self, other: &'b AffineNielsPoint) -> CompletedPoint

Performs the - operation.