Struct curve25519_dalek::window::LookupTable

pub struct LookupTable<T>(pub(crate) [T; 8]);

A lookup table of precomputed multiples of a point \(P\), used to compute \( xP \) for \( -8 \leq x \leq 8 \).

The computation of \( xP \) is done in constant time by the select function.

Since LookupTable does not implement Index, it’s more difficult to accidentally use the table directly. Unfortunately the table is only pub(crate) so that we can write hardcoded constants, so it’s still technically possible. It would be nice to prevent direct access to the table.

Tuple Fields

0: [T; 8]

Implementations

impl<T> LookupTable<T> where
    T: Identity + ConditionallySelectable + ConditionallyNegatable, 

pub fn select(&self, x: i8) -> T

Given \(-8 \leq x \leq 8\), return \(xP\) in constant time.

Trait Implementations

impl<T: Clone> Clone for LookupTable<T>

fn clone(&self) -> LookupTable<T>

Returns a copy of the value.

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

Performs copy-assignment from source.

impl<T: Debug> Debug for LookupTable<T>

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

Formats the value using the given formatter.

impl<T: Copy + Default> Default for LookupTable<T>

fn default() -> LookupTable<T>

Returns the “default value” for a type.

impl<'a> From<&'a EdwardsPoint> for LookupTable<CachedPoint>

This is supported on target feature avx2 and non-target feature avx512ifma and crate feature simd_backend and (target features avx2 or avx512ifma) only.

fn from(point: &'a EdwardsPoint) -> Self

Performs the conversion.

impl<'a> From<&'a EdwardsPoint> for LookupTable<CachedPoint>

This is supported on crate feature simd_backend and (target features avx2 or avx512ifma) and target feature avx512ifma only.

fn from(point: &'a EdwardsPoint) -> Self

Performs the conversion.

impl<'a> From<&'a EdwardsPoint> for LookupTable<ProjectiveNielsPoint>

fn from(P: &'a EdwardsPoint) -> Self

Performs the conversion.

impl<'a> From<&'a EdwardsPoint> for LookupTable<AffineNielsPoint>

fn from(P: &'a EdwardsPoint) -> Self

Performs the conversion.

impl<T> Zeroize for LookupTable<T> where
    T: Copy + Default + Zeroize, 

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<T: Copy> Copy for LookupTable<T>