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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::CipherSuite;
/// Elliptic curve types
#[derive(Clone, Copy, Debug, Eq, PartialEq)]
#[repr(u8)]
#[non_exhaustive]
pub enum Curve {
/// NIST Curve-P256
P256,
/// NIST Curve-P384
P384,
/// NIST Curve-P521
P521,
/// Elliptic-curve Diffie-Hellman key exchange Curve25519
X25519,
/// Edwards-curve Digital Signature Algorithm Curve25519
Ed25519,
/// Elliptic-curve Diffie-Hellman key exchange Curve448
X448,
/// Edwards-curve Digital Signature Algorithm Curve448
Ed448,
}
impl Curve {
/// Returns the amount of bytes of a secret key using this curve
#[inline(always)]
pub fn secret_key_size(&self) -> usize {
match self {
Curve::P256 => 32,
Curve::P384 => 48,
Curve::P521 => 66,
Curve::X25519 => 32,
Curve::Ed25519 => 64,
Curve::X448 => 56,
Curve::Ed448 => 114,
}
}
#[inline(always)]
pub fn public_key_size(&self) -> usize {
match self {
Curve::P256 | Curve::P384 | Curve::P521 => 2 * self.secret_key_size() + 1,
Curve::X25519 | Curve::Ed25519 | Curve::X448 | Curve::Ed448 => self.secret_key_size(),
}
}
pub fn from_ciphersuite(cipher_suite: CipherSuite, for_sig: bool) -> Option<Self> {
match cipher_suite {
CipherSuite::P256_AES128 => Some(Curve::P256),
CipherSuite::P384_AES256 => Some(Curve::P384),
CipherSuite::P521_AES256 => Some(Curve::P521),
CipherSuite::CURVE25519_AES128 | CipherSuite::CURVE25519_CHACHA if for_sig => {
Some(Curve::Ed25519)
}
CipherSuite::CURVE25519_AES128 | CipherSuite::CURVE25519_CHACHA => Some(Curve::X25519),
CipherSuite::CURVE448_AES256 | CipherSuite::CURVE448_CHACHA if for_sig => {
Some(Curve::Ed448)
}
CipherSuite::CURVE448_AES256 | CipherSuite::CURVE448_CHACHA => Some(Curve::X448),
_ => None,
}
}
#[inline(always)]
pub fn curve_bitmask(&self) -> Option<u8> {
match self {
Curve::P256 | Curve::P384 => Some(0xFF),
Curve::P521 => Some(0x01),
_ => None,
}
}
}