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use super::Scalar;
use core::borrow::Borrow;
use elliptic_curve::{
group::ff::Field, ops::Invert, rand_core::CryptoRngCore, subtle::CtOption, zeroize::Zeroize,
};
#[derive(Clone)]
#[cfg_attr(docsrs, doc(cfg(feature = "arithmetic")))]
pub struct BlindedScalar {
scalar: Scalar,
mask: Scalar,
}
impl BlindedScalar {
pub fn new(scalar: Scalar, rng: &mut impl CryptoRngCore) -> Self {
Self {
scalar,
mask: Scalar::random(rng),
}
}
}
impl Borrow<Scalar> for BlindedScalar {
fn borrow(&self) -> &Scalar {
&self.scalar
}
}
impl Invert for BlindedScalar {
type Output = CtOption<Scalar>;
fn invert(&self) -> CtOption<Scalar> {
(self.scalar * self.mask)
.invert_vartime()
.map(|s| s * self.mask)
}
}
impl Zeroize for BlindedScalar {
fn zeroize(&mut self) {
self.scalar.zeroize();
self.mask.zeroize();
}
}
impl Drop for BlindedScalar {
fn drop(&mut self) {
self.zeroize();
}
}