1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58
// Copyright 2022 Parity Technologies (UK) Ltd.
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the "Software"),
// to deal in the Software without restriction, including without limitation
// the rights to use, copy, modify, merge, publish, distribute, sublicense,
// and/or sell copies of the Software, and to permit persons to whom the
// Software is furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
// DEALINGS IN THE SOFTWARE.
//! Mixnet key-exchange key pair.
use super::sphinx::{
derive_kx_public, derive_kx_shared_secret, gen_kx_secret, KxPublic, KxSecret, SharedSecret,
};
use rand::{CryptoRng, Rng};
use zeroize::Zeroizing;
pub struct KxPair {
/// Unclamped secret key. Boxed to avoid leaving copies around in memory if `KxPair` is moved.
secret: Box<Zeroizing<KxSecret>>,
public: KxPublic,
}
impl KxPair {
pub fn gen(rng: &mut (impl Rng + CryptoRng)) -> Self {
gen_kx_secret(rng).into()
}
pub fn public(&self) -> &KxPublic {
&self.public
}
pub fn exchange(&self, their_public: &KxPublic) -> SharedSecret {
derive_kx_shared_secret(their_public, self.secret.as_ref())
}
}
impl From<KxSecret> for KxPair {
fn from(secret: KxSecret) -> Self {
// We box the secret to avoid leaving copies of it in memory when the KxPair is moved. Note
// that we will likely leave some copies on the stack here; I'm not aware of any good way
// of avoiding this.
let secret = Box::new(Zeroizing::new(secret));
let public = derive_kx_public(secret.as_ref());
Self { secret, public }
}
}