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//! Scalar types.
#[cfg(feature = "arithmetic")]
mod blinded;
#[cfg(feature = "arithmetic")]
mod nonzero;
mod primitive;
pub use self::primitive::ScalarPrimitive;
#[cfg(feature = "arithmetic")]
pub use self::{blinded::BlindedScalar, nonzero::NonZeroScalar};
use crypto_bigint::Integer;
use subtle::Choice;
#[cfg(feature = "arithmetic")]
use crate::CurveArithmetic;
/// Scalar field element for a particular elliptic curve.
#[cfg(feature = "arithmetic")]
pub type Scalar<C> = <C as CurveArithmetic>::Scalar;
/// Bit representation of a scalar field element of a given curve.
#[cfg(feature = "bits")]
pub type ScalarBits<C> = ff::FieldBits<<Scalar<C> as ff::PrimeFieldBits>::ReprBits>;
/// Instantiate a scalar from an unsigned integer without checking for overflow.
pub trait FromUintUnchecked {
/// Unsigned integer type (i.e. `Curve::Uint`)
type Uint: Integer;
/// Instantiate scalar from an unsigned integer without checking
/// whether the value overflows the field modulus.
///
/// ⚠️ WARNING!
///
/// Incorrectly used this can lead to mathematically invalid results,
/// which can lead to potential security vulnerabilities.
///
/// Use with care!
fn from_uint_unchecked(uint: Self::Uint) -> Self;
}
/// Is this scalar greater than n / 2?
///
/// # Returns
///
/// - For scalars 0 through n / 2: `Choice::from(0)`
/// - For scalars (n / 2) + 1 through n - 1: `Choice::from(1)`
pub trait IsHigh {
/// Is this scalar greater than or equal to n / 2?
fn is_high(&self) -> Choice;
}
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