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https://github.com/saymrwulf/curve25519-dalek-source.git
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a3f53c9134
Originally this was for hygiene, so that we could erase points from heap-allocated memory in multiscalar_mult, but it ends up providing a cleaner API for scalar multiplication. It's kept inside curve_models for now, but it could go somewhere else if that's a better place.
53 lines
1.7 KiB
Rust
53 lines
1.7 KiB
Rust
// -*- mode: rust; -*-
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//
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// This file is part of curve25519-dalek.
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// Copyright (c) 2016-2017 Isis Lovecruft, Henry de Valence
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// See LICENSE for licensing information.
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//
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// Authors:
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// - Isis Agora Lovecruft <isis@patternsinthevoid.net>
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// - Henry de Valence <hdevalence@hdevalence.ca>
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//! Module for common traits.
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use subtle;
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// ------------------------------------------------------------------------
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// Public Traits
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// ------------------------------------------------------------------------
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/// Trait for getting the identity element of a point type.
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pub trait Identity {
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/// Returns the identity element of the curve.
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/// Can be used as a constructor.
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fn identity() -> Self;
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}
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/// Trait for testing if a curve point is equivalent to the identity point.
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pub trait IsIdentity {
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/// Return true if this element is the identity element of the curve.
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fn is_identity(&self) -> bool;
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}
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/// Implement generic identity equality testing for a point representations
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/// which have constant-time equality testing and a defined identity
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/// constructor.
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impl<T> IsIdentity for T where T: subtle::Equal + Identity {
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fn is_identity(&self) -> bool {
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self.ct_eq(&T::identity()) == 1u8
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}
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}
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// ------------------------------------------------------------------------
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// Private Traits
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// ------------------------------------------------------------------------
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/// Trait for checking whether a point is on the curve.
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///
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/// This trait is only for debugging/testing, since it should be
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/// impossible for a `curve25519-dalek` user to construct an invalid
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/// point.
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pub(crate) trait ValidityCheck {
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/// Checks whether the point is on the curve. Not CT.
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fn is_valid(&self) -> bool;
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}
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