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.

XXX make this generic with respect to table size

Methods

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: Copy> Copy for LookupTable<T>

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<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.