Trait holochain_types::prelude::dependencies::subtle::ConditionallySelectable [−][src]
pub trait ConditionallySelectable: Copy { fn conditional_select(a: &Self, b: &Self, choice: Choice) -> Self; fn conditional_assign(&mut self, other: &Self, choice: Choice) { ... } fn conditional_swap(a: &mut Self, b: &mut Self, choice: Choice) { ... } }
Expand description
A type which can be conditionally selected in constant time.
This trait also provides generic implementations of conditional assignment and conditional swaps.
Required methods
fn conditional_select(a: &Self, b: &Self, choice: Choice) -> Self
fn conditional_select(a: &Self, b: &Self, choice: Choice) -> Self
Select a
or b
according to choice
.
Returns
a
ifchoice == Choice(0)
;b
ifchoice == Choice(1)
.
This function should execute in constant time.
Example
use subtle::ConditionallySelectable; let x: u8 = 13; let y: u8 = 42; let z = u8::conditional_select(&x, &y, 0.into()); assert_eq!(z, x); let z = u8::conditional_select(&x, &y, 1.into()); assert_eq!(z, y);
Provided methods
fn conditional_assign(&mut self, other: &Self, choice: Choice)
fn conditional_assign(&mut self, other: &Self, choice: Choice)
Conditionally assign other
to self
, according to choice
.
This function should execute in constant time.
Example
use subtle::ConditionallySelectable; let mut x: u8 = 13; let mut y: u8 = 42; x.conditional_assign(&y, 0.into()); assert_eq!(x, 13); x.conditional_assign(&y, 1.into()); assert_eq!(x, 42);
fn conditional_swap(a: &mut Self, b: &mut Self, choice: 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.
This function should execute in constant time.
Example
use subtle::ConditionallySelectable; let mut x: u8 = 13; let mut y: u8 = 42; u8::conditional_swap(&mut x, &mut y, 0.into()); assert_eq!(x, 13); assert_eq!(y, 42); u8::conditional_swap(&mut x, &mut y, 1.into()); assert_eq!(x, 42); assert_eq!(y, 13);
Implementations on Foreign Types
pub fn conditional_select(
a: &RistrettoPoint,
b: &RistrettoPoint,
choice: Choice
) -> RistrettoPoint
pub fn conditional_select(
a: &RistrettoPoint,
b: &RistrettoPoint,
choice: Choice
) -> RistrettoPoint
Conditionally select between self
and other
.
Example
use subtle::ConditionallySelectable; use subtle::Choice; let A = RistrettoPoint::identity(); let B = constants::RISTRETTO_BASEPOINT_POINT; let mut P = A; P = RistrettoPoint::conditional_select(&A, &B, Choice::from(0)); assert_eq!(P, A); P = RistrettoPoint::conditional_select(&A, &B, Choice::from(1)); assert_eq!(P, B);