Struct Scalar 

pub struct Scalar([u8; 32]);

A reduced scalar.

Tuple Fields

0: [u8; 32]

Implementations

impl Scalar

pub const ZERO: Self

The additive identity.

pub const ONE: Self

The multiplicative identity.

pub const INV_EIGHT: Self

The multiplicative inverse of 8 \mod l.

l is defined as the largest prime factor in the amount of points on the Ed25519 elliptic curve.

This is useful as part of clearing terms belonging to a small-order subgroup from within a point.

pub fn write<W: Write>(&self, w: &mut W) -> Result<()>

Write a Scalar.

This may run in variable time.

pub fn read<R: Read>(r: &mut R) -> Result<Scalar>

Read a canonically-encoded scalar.

Some scalars within the Monero protocol are not enforced to be canonically encoded. For such scalars, they should be represented as [u8; 32] and later converted to scalars as relevant.

This may run in variable time.

#[doc(hidden)] pub fn from(scalar: Scalar) -> Self

Create a Scalar from a curve25519_dalek::Scalar.

This is not a public function as it is not part of our API commitment.

#[doc(hidden)] pub fn into(self) -> Scalar

Create a curve25519_dalek::Scalar from a Scalar.

This is hidden as it is not part of our API commitment. No guarantees are made for it.

#[doc(hidden)] pub fn random(rng: &mut (impl RngCore + CryptoRng)) -> Self

Sample a uniform Scalar from an RNG.

This is hidden as it is not part of our API commitment. No guarantees are made for it.

pub fn hash(data: impl AsRef<[u8]>) -> Self

Sample a scalar via hash function.

The implementation of this is keccak256(data) % l, where l is the largest prime factor in the amount of points on the Ed25519 elliptic curve. Notably, this is not a wide reduction.

This function panics if it finds a Keccak-256 preimage for an encoding of a multiple of l.

Trait Implementations

impl Clone for Scalar

fn clone(&self) -> Scalar

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl ConditionallySelectable for Scalar

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 Scalar

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 Scalar

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

Formats the value using the given formatter.

impl Eq for Scalar

#[doc(hidden)] fn assert_receiver_is_total_eq(&self)

impl From<Scalar> for [u8; 32]

fn from(scalar: Scalar) -> [u8; 32]

Converts to this type from the input type.

impl PartialEq for Scalar

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

This defers to ConstantTimeEq::ct_eq.

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 Scalar

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 Scalar

impl TrivialClone for Scalar