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// Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
// Copyright by contributors to this project.
// SPDX-License-Identifier: (Apache-2.0 OR MIT)
use mls_rs_core::{
crypto::{HpkePublicKey, HpkeSecretKey},
error::IntoAnyError,
};
use alloc::vec::Vec;
#[cfg(feature = "mock")]
use mockall::automock;
/// A trait that provides the required DH functions, as in RFC 9180,Section 4.1
#[cfg_attr(feature = "mock", automock(type Error = crate::mock::TestError;))]
#[cfg_attr(not(mls_build_async), maybe_async::must_be_sync)]
#[cfg_attr(all(target_arch = "wasm32", mls_build_async), maybe_async::must_be_async(?Send))]
#[cfg_attr(
all(not(target_arch = "wasm32"), mls_build_async),
maybe_async::must_be_async
)]
pub trait DhType: Send + Sync {
type Error: IntoAnyError + Send + Sync;
async fn dh(
&self,
secret_key: &HpkeSecretKey,
public_key: &HpkePublicKey,
) -> Result<Vec<u8>, Self::Error>;
/// Generate a fresh key pair. This is the only place where randomness is used in this
/// module. The function could be implemented in the same way as `derive` with random
/// `ikm`, but it could also be implemented directly with a crypto provider like OpenSSL.
async fn generate(&self) -> Result<(HpkeSecretKey, HpkePublicKey), Self::Error>;
/// Outputs the public key corresponding to the given secret key bytes. If the secret
/// key is malformed, the function should return an error.
async fn to_public(&self, secret_key: &HpkeSecretKey) -> Result<HpkePublicKey, Self::Error>;
/// If the output is `Some(bitmask)`, then the `Kem::derive` function will generate
/// the secret key by rejection sampling over random byte sequences with `bitmask`
/// applied to the most significant byte.
///
/// Typical outputs for ECDH are:
/// * `None` for curves 25519 and X448 (no rejection sampling is needed),
/// * `Some(0x01)` for curve P-521 (all bits of the first byte except the least
/// significant one are filtered out),
/// * `Some(0xFF)`for curves P-256 and P-384 (rejection sampling is needed but no
/// bits need to be filtered).
fn bitmask_for_rejection_sampling(&self) -> Option<u8>;
fn secret_key_size(&self) -> usize;
fn public_key_validate(&self, key: &HpkePublicKey) -> Result<(), Self::Error>;
}