Struct MontgomeryPoint

pub struct MontgomeryPoint(pub [u8; 32]);

Holds the \(u\)-coordinate of a point on the Montgomery form of Curve25519 or its twist.

Tuple Fields

0: [u8; 32]

Implementations

impl MontgomeryPoint

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

Fixed-base scalar multiplication (i.e. multiplication by the base point).

pub fn mul_clamped(self, bytes: [u8; 32]) -> Self

Multiply this point by clamp_integer(bytes). For a description of clamping, see clamp_integer.

pub fn mul_base_clamped(bytes: [u8; 32]) -> Self

Multiply the basepoint by clamp_integer(bytes). For a description of clamping, see clamp_integer.

pub fn mul_bits_be(&self, bits: impl Iterator<Item = bool>) -> MontgomeryPoint

Given self \( = u_0(P) \), and a big-endian bit representation of an integer \(n\), return \( u_0([n]P) \). This is constant time in the length of bits.

NOTE: You probably do not want to use this function. Almost every protocol built on Curve25519 uses clamped multiplication, explained here. When in doubt, use Self::mul_clamped.

pub const fn as_bytes(&self) -> &[u8; 32]

View this MontgomeryPoint as an array of bytes.

pub const fn to_bytes(&self) -> [u8; 32]

Convert this MontgomeryPoint to an array of bytes.

pub fn to_edwards(&self, sign: u8) -> Option<EdwardsPoint>

Attempt to convert to an EdwardsPoint, using the supplied choice of sign for the EdwardsPoint.

Inputs

• sign: a u8 donating the desired sign of the resulting EdwardsPoint. 0 denotes positive and 1 negative.

Return

• Some(EdwardsPoint) if self is the \(u\)-coordinate of a point on (the Montgomery form of) Curve25519;

• None if self is the \(u\)-coordinate of a point on the twist of (the Montgomery form of) Curve25519;

Trait Implementations

impl Clone for MontgomeryPoint

fn clone(&self) -> MontgomeryPoint

Returns a copy of the value.

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

Performs copy-assignment from source.

impl ConstantTimeEq for MontgomeryPoint

Equality of MontgomeryPoints is defined mod p.

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

Determine if two items are equal.

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

Determine if two items are NOT equal.

impl Debug for MontgomeryPoint

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

Formats the value using the given formatter.

impl Default for MontgomeryPoint

fn default() -> MontgomeryPoint

Returns the “default value” for a type.

impl Hash for MontgomeryPoint

fn hash<H: Hasher>(&self, state: &mut H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl Identity for MontgomeryPoint

fn identity() -> MontgomeryPoint

Return the group identity element, which has order 4.

impl Mul<&MontgomeryPoint> for &Scalar

type Output = MontgomeryPoint

The resulting type after applying the * operator.

fn mul(self, point: &MontgomeryPoint) -> MontgomeryPoint

Performs the * operation.

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

type Output = MontgomeryPoint

The resulting type after applying the * operator.

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

Performs the * operation.

impl Mul<&Scalar> for &MontgomeryPoint

Multiply this MontgomeryPoint by a Scalar.

fn mul(self, scalar: &Scalar) -> MontgomeryPoint

Given self \( = u_0(P) \), and a Scalar \(n\), return \( u_0([n]P) \)

type Output = MontgomeryPoint

The resulting type after applying the * operator.

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

type Output = MontgomeryPoint

The resulting type after applying the * operator.

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

Performs the * operation.

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

type Output = MontgomeryPoint

The resulting type after applying the * operator.

fn mul(self, rhs: MontgomeryPoint) -> MontgomeryPoint

Performs the * operation.

impl Mul<MontgomeryPoint> for Scalar

type Output = MontgomeryPoint

The resulting type after applying the * operator.

fn mul(self, rhs: MontgomeryPoint) -> MontgomeryPoint

Performs the * operation.

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

type Output = MontgomeryPoint

The resulting type after applying the * operator.

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

Performs the * operation.

impl Mul<Scalar> for MontgomeryPoint

type Output = MontgomeryPoint

The resulting type after applying the * operator.

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

Performs the * operation.

impl MulAssign<&Scalar> for MontgomeryPoint

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

Performs the *= operation.

impl MulAssign<Scalar> for MontgomeryPoint

fn mul_assign(&mut self, rhs: Scalar)

Performs the *= operation.

impl PartialEq for MontgomeryPoint

fn eq(&self, other: &MontgomeryPoint) -> 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 Zeroize for MontgomeryPoint

Available on crate feature zeroize only.

fn zeroize(&mut self)

Zero out this object from memory using Rust intrinsics which ensure the zeroization operation is not “optimized away” by the compiler.

impl Copy for MontgomeryPoint

impl Eq for MontgomeryPoint

Layout

Note: Most layout information is completely unstable and may even differ between compilations. The only exception is types with certain repr(...) attributes. Please see the Rust Reference's “Type Layout” chapter for details on type layout guarantees.

Size: 32 bytes