Files
rosenpass/oqs/src/kem_macro.rs
2025-04-03 16:55:03 +02:00

110 lines
5.0 KiB
Rust

//! Generic helpers for declaring bindings to liboqs kems
/// Generate bindings to a liboqs-provided KEM
macro_rules! oqs_kem {
($name:ident, $algo_trait:path) => { ::paste::paste!{
#[doc = "Bindings for ::oqs_sys::kem::" [<"OQS_KEM" _ $name:snake>] "_*"]
mod [< $name:snake >] {
use rosenpass_cipher_traits::primitives::{Kem, KemError};
#[doc = "Bindings for ::oqs_sys::kem::" [<"OQS_KEM" _ $name:snake>] "_*"]
#[doc = ""]
#[doc = "# Examples"]
#[doc = ""]
#[doc = "```rust"]
#[doc = "use std::borrow::{Borrow, BorrowMut};"]
#[doc = "use rosenpass_cipher_traits::primitives::Kem;"]
#[doc = "use rosenpass_oqs::" $name:camel " as MyKem;"]
#[doc = "use rosenpass_secret_memory::{Secret, Public};"]
#[doc = ""]
#[doc = "rosenpass_secret_memory::secret_policy_try_use_memfd_secrets();"]
#[doc = ""]
#[doc = "// Recipient generates secret key, transfers pk to sender"]
#[doc = "let mut sk = Secret::<{ MyKem::SK_LEN }>::zero();"]
#[doc = "let mut pk = Public::<{ MyKem::PK_LEN }>::zero();"]
#[doc = "MyKem.keygen(sk.secret_mut(), &mut pk);"]
#[doc = ""]
#[doc = "// Sender generates ciphertext and local shared key, sends ciphertext to recipient"]
#[doc = "let mut shk_enc = Secret::<{ MyKem::SHK_LEN }>::zero();"]
#[doc = "let mut ct = Public::<{ MyKem::CT_LEN }>::zero();"]
#[doc = "MyKem.encaps(shk_enc.secret_mut(), &mut ct, &pk);"]
#[doc = ""]
#[doc = "// Recipient decapsulates ciphertext"]
#[doc = "let mut shk_dec = Secret::<{ MyKem::SHK_LEN }>::zero();"]
#[doc = "MyKem.decaps(shk_dec.secret_mut(), sk.secret_mut(), &ct);"]
#[doc = ""]
#[doc = "// Both parties end up with the same shared key"]
#[doc = "assert!(rosenpass_constant_time::compare(shk_enc.secret(), shk_dec.secret()) == 0);"]
#[doc = "```"]
pub struct [< $name:camel >];
pub const SK_LEN: usize = ::oqs_sys::kem::[<OQS_KEM _ $name:snake _ length_secret_key >] as usize;
pub const PK_LEN: usize = ::oqs_sys::kem::[<OQS_KEM _ $name:snake _ length_public_key >] as usize;
pub const CT_LEN: usize = ::oqs_sys::kem::[<OQS_KEM _ $name:snake _ length_ciphertext >] as usize;
pub const SHK_LEN: usize = ::oqs_sys::kem::[<OQS_KEM _ $name:snake _ length_shared_secret >] as usize;
/// # Panic & Safety
///
/// This Trait impl calls unsafe [oqs_sys] functions, that write to byte
/// slices only identified using raw pointers. It must be ensured that the raw
/// pointers point into byte slices of sufficient length, to avoid UB through
/// overwriting of arbitrary data. This is ensured through assertions in the
/// implementation.
///
/// __Note__: This requirement is stricter than necessary, it would suffice
/// to only check that the buffers are big enough, allowing them to be even
/// bigger. However, from a correctness point of view it does not make sense to
/// allow bigger buffers.
impl Kem<SK_LEN, PK_LEN, CT_LEN, SHK_LEN> for [< $name:camel >] {
fn keygen(&self, sk: &mut [u8; SK_LEN], pk: &mut [u8; PK_LEN]) -> Result<(), KemError> {
unsafe {
oqs_call!(
::oqs_sys::kem::[< OQS_KEM _ $name:snake _ keypair >],
pk.as_mut_ptr(),
sk.as_mut_ptr()
);
}
Ok(())
}
fn encaps(&self, shk: &mut [u8; SHK_LEN], ct: &mut [u8; CT_LEN], pk: &[u8; PK_LEN]) -> Result<(), KemError> {
unsafe {
oqs_call!(
::oqs_sys::kem::[< OQS_KEM _ $name:snake _ encaps >],
ct.as_mut_ptr(),
shk.as_mut_ptr(),
pk.as_ptr()
);
}
Ok(())
}
fn decaps(&self, shk: &mut [u8; SHK_LEN], sk: &[u8; SK_LEN], ct: &[u8; CT_LEN]) -> Result<(), KemError> {
unsafe {
oqs_call!(
::oqs_sys::kem::[< OQS_KEM _ $name:snake _ decaps >],
shk.as_mut_ptr(),
ct.as_ptr(),
sk.as_ptr()
);
}
Ok(())
}
}
}
impl Default for [< $name:camel >] {
fn default() -> Self {
Self
}
}
impl $algo_trait for [< $name:camel >] {}
pub use [< $name:snake >] :: [< $name:camel >];
}}
}