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refactor(traits): migrate Kem error types to associated types #1552

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10 changes: 7 additions & 3 deletions crates/algorithms/curve25519/src/lib.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -36,11 +36,15 @@ trait Curve25519 {
pub struct X25519;

impl libcrux_traits::kem::arrayref::Kem<DK_LEN, EK_LEN, EK_LEN, SS_LEN, DK_LEN, DK_LEN> for X25519 {
type KeyGenError = libcrux_traits::kem::arrayref::KeyGenError;
type EncapsError = libcrux_traits::kem::arrayref::EncapsError;
type DecapsError = libcrux_traits::kem::arrayref::DecapsError;

fn keygen(
ek: &mut [u8; DK_LEN],
dk: &mut [U8; EK_LEN],
rand: &[U8; DK_LEN],
) -> Result<(), libcrux_traits::kem::arrayref::KeyGenError> {
) -> Result<(), Self::KeyGenError> {
dk.copy_from_slice(rand);
clamp(dk.declassify_ref_mut());
secret_to_public(ek, dk.declassify_ref());
Expand All @@ -52,7 +56,7 @@ impl libcrux_traits::kem::arrayref::Kem<DK_LEN, EK_LEN, EK_LEN, SS_LEN, DK_LEN,
ss: &mut [U8; SS_LEN],
ek: &[u8; EK_LEN],
rand: &[U8; DK_LEN],
) -> Result<(), libcrux_traits::kem::arrayref::EncapsError> {
) -> Result<(), Self::EncapsError> {
let mut eph_dk = *rand;
clamp(eph_dk.declassify_ref_mut());
secret_to_public(ct, eph_dk.declassify_ref());
Expand All @@ -65,7 +69,7 @@ impl libcrux_traits::kem::arrayref::Kem<DK_LEN, EK_LEN, EK_LEN, SS_LEN, DK_LEN,
ss: &mut [U8; SS_LEN],
ct: &[u8; DK_LEN],
dk: &[U8; EK_LEN],
) -> Result<(), libcrux_traits::kem::arrayref::DecapsError> {
) -> Result<(), Self::DecapsError> {
ecdh(ss.declassify_ref_mut(), ct, dk.declassify_ref())
.map_err(|_| libcrux_traits::kem::arrayref::DecapsError::Unknown)
}
Expand Down
10 changes: 7 additions & 3 deletions crates/algorithms/p256/src/impl_kem.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -13,11 +13,15 @@ const RAND_KEYGEN_LEN: usize = SCALAR_LEN;
const RAND_ENCAPS_LEN: usize = SCALAR_LEN;

impl Kem<EK_LEN, DK_LEN, CT_LEN, SS_LEN, RAND_KEYGEN_LEN, RAND_ENCAPS_LEN> for super::P256 {
type KeyGenError = KeyGenError;
type EncapsError = EncapsError;
type DecapsError = DecapsError;

fn keygen(
ek: &mut [u8; EK_LEN],
dk: &mut [U8; DK_LEN],
rand: &[U8; RAND_KEYGEN_LEN],
) -> Result<(), KeyGenError> {
) -> Result<(), Self::KeyGenError> {
if !super::p256::validate_private_key(rand.as_slice().declassify_ref()) {
return Err(KeyGenError::InvalidRandomness);
}
Expand All @@ -35,7 +39,7 @@ impl Kem<EK_LEN, DK_LEN, CT_LEN, SS_LEN, RAND_KEYGEN_LEN, RAND_ENCAPS_LEN> for s
ss: &mut [U8; SS_LEN],
ek: &[u8; EK_LEN],
rand: &[U8; RAND_ENCAPS_LEN],
) -> Result<(), EncapsError> {
) -> Result<(), Self::EncapsError> {
if !super::p256::validate_public_key(ek) {
return Err(EncapsError::InvalidEncapsKey);
}
Expand All @@ -59,7 +63,7 @@ impl Kem<EK_LEN, DK_LEN, CT_LEN, SS_LEN, RAND_KEYGEN_LEN, RAND_ENCAPS_LEN> for s
ss: &mut [U8; SS_LEN],
ct: &[u8; CT_LEN],
dk: &[U8; DK_LEN],
) -> Result<(), DecapsError> {
) -> Result<(), Self::DecapsError> {
if !super::p256::validate_public_key(ct) {
return Err(DecapsError::InvalidCiphertext);
}
Expand Down
10 changes: 7 additions & 3 deletions libcrux-kem/src/kem.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -937,6 +937,10 @@ mod xwing {
RAND_ENCAPS_LEN,
> for XWing
{
type KeyGenError = libcrux_traits::kem::owned::KeyGenError;
type EncapsError = libcrux_traits::kem::owned::EncapsError;
type DecapsError = libcrux_traits::kem::owned::DecapsError;

fn keygen(
ek: &mut [u8; EK_LEN],
dk: &mut [u8; DK_LEN],
Expand All @@ -957,7 +961,7 @@ mod xwing {
let dk_m: &mut [u8; MLKEM768_DK_LEN] = dk_m.try_into().unwrap();
let dk_x: &mut [u8; X25519_DK_LEN] = dk_x.try_into().unwrap();

MlKem768::keygen(ek_m, dk_m, rand_m)?;
MlKem768::keygen(ek_m, dk_m, rand_m).unwrap();
X25519::keygen(ek_x, dk_x, rand_x)?;

Ok(())
Expand Down Expand Up @@ -986,7 +990,7 @@ mod xwing {
hash_buffer[128..134].copy_from_slice(&[0x5c, 0x2e, 0x2f, 0x2f, 0x5e, 0x5c]);

let ss_m: &mut [u8; 32] = (&mut hash_buffer[0..32]).try_into().unwrap();
MlKem768::encaps(ct_m, ss_m, ek_m, rand_m)?;
MlKem768::encaps(ct_m, ss_m, ek_m, rand_m).unwrap();

let ss_x: &mut [u8; 32] = (&mut hash_buffer[32..64]).try_into().unwrap();
X25519::encaps(ct_x, ss_x, ek_x, rand_x)?;
Expand Down Expand Up @@ -1018,7 +1022,7 @@ mod xwing {
hash_buffer[128..134].copy_from_slice(&[0x5c, 0x2e, 0x2f, 0x2f, 0x5e, 0x5c]);

let ss_m: &mut [u8; 32] = (&mut hash_buffer[0..32]).try_into().unwrap();
MlKem768::decaps(ss_m, ct_m, dk_m)?;
MlKem768::decaps(ss_m, ct_m, dk_m).unwrap();

let ss_x: &mut [u8; 32] = (&mut hash_buffer[32..64]).try_into().unwrap();
X25519::decaps(ss_x, ct_x, dk_x)?;
Expand Down
10 changes: 7 additions & 3 deletions libcrux-ml-kem/src/lib.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -127,11 +127,15 @@ macro_rules! impl_kem_trait {
SHARED_SECRET_SIZE,
> for $variant
{
type KeyGenError = core::convert::Infallible;
type EncapsError = core::convert::Infallible;
type DecapsError = core::convert::Infallible;

fn keygen(
ek: &mut [u8; CPA_PKE_PUBLIC_KEY_SIZE],
dk: &mut [u8; SECRET_KEY_SIZE],
rand: &[u8; KEY_GENERATION_SEED_SIZE],
) -> Result<(), libcrux_traits::kem::owned::KeyGenError> {
) -> Result<(), Self::KeyGenError> {
let key_pair = generate_key_pair(*rand);
ek.copy_from_slice(key_pair.pk());
dk.copy_from_slice(key_pair.sk());
Expand All @@ -144,7 +148,7 @@ macro_rules! impl_kem_trait {
ss: &mut [u8; SHARED_SECRET_SIZE],
ek: &[u8; CPA_PKE_PUBLIC_KEY_SIZE],
rand: &[u8; SHARED_SECRET_SIZE],
) -> Result<(), libcrux_traits::kem::owned::EncapsError> {
) -> Result<(), Self::EncapsError> {
let public_key: $pk = ek.into();

let (ct_, ss_) = encapsulate(&public_key, *rand);
Expand All @@ -158,7 +162,7 @@ macro_rules! impl_kem_trait {
ss: &mut [u8; SHARED_SECRET_SIZE],
ct: &[u8; CPA_PKE_CIPHERTEXT_SIZE],
dk: &[u8; SECRET_KEY_SIZE],
) -> Result<(), libcrux_traits::kem::owned::DecapsError> {
) -> Result<(), Self::DecapsError> {
let secret_key: $sk = dk.into();
let ciphertext: $ct = ct.into();

Expand Down
13 changes: 10 additions & 3 deletions traits/src/kem/arrayref.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -14,14 +14,21 @@ pub trait Kem<
const RAND_ENCAPS_LEN: usize,
>
{
/// Error type for key generation
type KeyGenError: core::fmt::Debug;
/// Error type for encapsulation
type EncapsError: core::fmt::Debug;
/// Error type for decapsulation
type DecapsError: core::fmt::Debug;

/// Generate a pair of encapsulation and decapsulation keys.
/// It is the responsibility of the caller to ensure that the `rand` argument is actually
/// random.
fn keygen(
ek: &mut [u8; EK_LEN],
dk: &mut [U8; DK_LEN],
rand: &[U8; RAND_KEYGEN_LEN],
) -> Result<(), KeyGenError>;
) -> Result<(), Self::KeyGenError>;

/// Encapsulate a shared secret towards a given encapsulation key.
/// It is the responsibility of the caller to ensure that the `rand` argument is actually
Expand All @@ -31,14 +38,14 @@ pub trait Kem<
ss: &mut [U8; SS_LEN],
ek: &[u8; EK_LEN],
rand: &[U8; RAND_ENCAPS_LEN],
) -> Result<(), EncapsError>;
) -> Result<(), Self::EncapsError>;

/// Decapsulate a shared secret.
fn decaps(
ss: &mut [U8; SS_LEN],
ct: &[u8; CT_LEN],
dk: &[U8; DK_LEN],
) -> Result<(), DecapsError>;
) -> Result<(), Self::DecapsError>;
}

/// Error generating key with provided randomness
Expand Down
20 changes: 14 additions & 6 deletions traits/src/kem/owned.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -18,21 +18,25 @@ pub trait Kem<
const RAND_ENCAPS_LEN: usize,
>
{
type KeyGenError: core::fmt::Debug;
type EncapsError: core::fmt::Debug;
type DecapsError: core::fmt::Debug;

/// Generate a pair of encapsulation and decapsulation keys.
/// It is the responsibility of the caller to ensure that the `rand` argument is actually
/// random.
fn keygen(rand: &[U8; RAND_KEYGEN_LEN]) -> Result<([U8; DK_LEN], [u8; EK_LEN]), KeyGenError>;
fn keygen(rand: &[U8; RAND_KEYGEN_LEN]) -> Result<([U8; DK_LEN], [u8; EK_LEN]), Self::KeyGenError>;

/// Encapsulate a shared secret towards a given encapsulation key.
/// It is the responsibility of the caller to ensure that the `rand` argument is actually
/// random.
fn encaps(
ek: &[u8; EK_LEN],
rand: &[U8; RAND_ENCAPS_LEN],
) -> Result<([U8; SS_LEN], [u8; CT_LEN]), EncapsError>;
) -> Result<([U8; SS_LEN], [u8; CT_LEN]), Self::EncapsError>;

/// Decapsulate a shared secret.
fn decaps(ct: &[u8; CT_LEN], dk: &[U8; DK_LEN]) -> Result<[U8; SS_LEN], DecapsError>;
fn decaps(ct: &[u8; CT_LEN], dk: &[U8; DK_LEN]) -> Result<[U8; SS_LEN], Self::DecapsError>;
}

impl<
Expand All @@ -45,7 +49,11 @@ impl<
T: arrayref::Kem<EK_LEN, DK_LEN, CT_LEN, SS_LEN, RAND_KEYGEN_LEN, RAND_ENCAPS_LEN>,
> Kem<EK_LEN, DK_LEN, CT_LEN, SS_LEN, RAND_KEYGEN_LEN, RAND_ENCAPS_LEN> for T
{
fn keygen(rand: &[U8; RAND_KEYGEN_LEN]) -> Result<([U8; DK_LEN], [u8; EK_LEN]), KeyGenError> {
type KeyGenError = T::KeyGenError;
type EncapsError = T::EncapsError;
type DecapsError = T::DecapsError;

fn keygen(rand: &[U8; RAND_KEYGEN_LEN]) -> Result<([U8; DK_LEN], [u8; EK_LEN]), Self::KeyGenError> {
let mut dk = [0u8.classify(); DK_LEN];
let mut ek = [0u8; EK_LEN];

Expand All @@ -64,7 +72,7 @@ impl<
fn encaps(
ek: &[u8; EK_LEN],
rand: &[U8; RAND_ENCAPS_LEN],
) -> Result<([U8; SS_LEN], [u8; CT_LEN]), EncapsError> {
) -> Result<([U8; SS_LEN], [u8; CT_LEN]), Self::EncapsError> {
let mut ss = [0u8.classify(); SS_LEN];
let mut ct = [0u8; CT_LEN];

Expand All @@ -80,7 +88,7 @@ impl<
Ok((ss, ct))
}

fn decaps(ct: &[u8; CT_LEN], dk: &[U8; DK_LEN]) -> Result<[U8; SS_LEN], DecapsError> {
fn decaps(ct: &[u8; CT_LEN], dk: &[U8; DK_LEN]) -> Result<[U8; SS_LEN], Self::DecapsError> {
let mut ss = [0u8.classify(); SS_LEN];

<Self as arrayref::Kem<
Expand Down
32 changes: 23 additions & 9 deletions traits/src/kem/slice.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -7,18 +7,25 @@ use super::arrayref;

/// A Key Encapsulation Mechanismd (KEM). This trait takes slices as arguments.
pub trait Kem {
/// Error type for key generation
type KeyGenError: core::fmt::Debug;
/// Error type for encapsulation
type EncapsError: core::fmt::Debug;
/// Error type for decapsulation
type DecapsError: core::fmt::Debug;

/// Generate a pair of encapsulation and decapsulation keys.
/// It is the responsibility of the caller to ensure that the `rand` argument is actually
/// random.
fn keygen(ek: &mut [u8], dk: &mut [U8], rand: &[U8]) -> Result<(), KeyGenError>;
fn keygen(ek: &mut [u8], dk: &mut [U8], rand: &[U8]) -> Result<(), Self::KeyGenError>;

/// Encapsulate a shared secret towards a given encapsulation key.
/// It is the responsibility of the caller to ensure that the `rand` argument is actually
/// random.
fn encaps(ct: &mut [u8], ss: &mut [U8], ek: &[u8], rand: &[U8]) -> Result<(), EncapsError>;
fn encaps(ct: &mut [u8], ss: &mut [U8], ek: &[u8], rand: &[U8]) -> Result<(), Self::EncapsError>;

/// Decapsulate a shared secret.
fn decaps(ss: &mut [U8], ct: &[u8], dk: &[U8]) -> Result<(), DecapsError>;
fn decaps(ss: &mut [U8], ct: &[u8], dk: &[U8]) -> Result<(), Self::DecapsError>;
}

/// Error generating key with provided randomness
Expand Down Expand Up @@ -106,7 +113,11 @@ impl From<arrayref::DecapsError> for DecapsError {
macro_rules! impl_trait {
($type:ty => $ek:expr, $dk:expr, $ct:expr, $ss:expr, $rand_kg:expr, $rand_encaps:expr) => {
impl $crate::kem::slice::Kem for $type {
fn keygen(ek: &mut [u8], dk: &mut [$crate::libcrux_secrets::U8], rand: &[$crate::libcrux_secrets::U8]) -> Result<(), $crate::kem::slice::KeyGenError> {
type KeyGenError = $crate::kem::slice::KeyGenError;
type EncapsError = $crate::kem::slice::EncapsError;
type DecapsError = $crate::kem::slice::DecapsError;

fn keygen(ek: &mut [u8], dk: &mut [$crate::libcrux_secrets::U8], rand: &[$crate::libcrux_secrets::U8]) -> Result<(), Self::KeyGenError> {
let ek : &mut [u8; $ek] = ek
.try_into()
.map_err(|_| $crate::kem::slice::KeyGenError::InvalidEncapsKeyLength)?;
Expand All @@ -117,10 +128,11 @@ macro_rules! impl_trait {
.try_into()
.map_err(|_| $crate::kem::slice::KeyGenError::InvalidRandomnessLength)?;

<$type as $crate::kem::arrayref::Kem<$ek, $dk, $ct, $ss, $rand_kg, $rand_encaps>>::keygen(ek, dk, rand).map_err($crate::kem::slice::KeyGenError::from)
<$type as $crate::kem::arrayref::Kem<$ek, $dk, $ct, $ss, $rand_kg, $rand_encaps>>::keygen(ek, dk, rand)
.map_err(|_| $crate::kem::slice::KeyGenError::Unknown)
}

fn encaps(ct: &mut [u8], ss: &mut [$crate::libcrux_secrets::U8], ek: &[u8], rand: &[$crate::libcrux_secrets::U8]) -> Result<(), $crate::kem::slice::EncapsError>{
fn encaps(ct: &mut [u8], ss: &mut [$crate::libcrux_secrets::U8], ek: &[u8], rand: &[$crate::libcrux_secrets::U8]) -> Result<(), Self::EncapsError>{
let ct : &mut [u8; $ct] = ct
.try_into()
.map_err(|_| $crate::kem::slice::EncapsError::InvalidCiphertextLength)?;
Expand All @@ -135,10 +147,11 @@ macro_rules! impl_trait {
.map_err(|_| $crate::kem::slice::EncapsError::InvalidRandomnessLength)?;


<$type as $crate::kem::arrayref::Kem<$ek, $dk, $ct, $ss, $rand_kg, $rand_encaps>>::encaps(ct, ss, ek,rand).map_err($crate::kem::slice::EncapsError::from)
<$type as $crate::kem::arrayref::Kem<$ek, $dk, $ct, $ss, $rand_kg, $rand_encaps>>::encaps(ct, ss, ek,rand)
.map_err(|_| $crate::kem::slice::EncapsError::Unknown)
}

fn decaps(ss: &mut [$crate::libcrux_secrets::U8], ct: &[u8], dk: &[$crate::libcrux_secrets::U8]) -> Result<(), $crate::kem::slice::DecapsError> {
fn decaps(ss: &mut [$crate::libcrux_secrets::U8], ct: &[u8], dk: &[$crate::libcrux_secrets::U8]) -> Result<(), Self::DecapsError> {
let ss : &mut [$crate::libcrux_secrets::U8; $ss] = ss
.try_into()
.map_err(|_| $crate::kem::slice::DecapsError::InvalidSharedSecretLength)?;
Expand All @@ -149,7 +162,8 @@ macro_rules! impl_trait {
.try_into()
.map_err(|_| $crate::kem::slice::DecapsError::InvalidDecapsKeyLength)?;

<$type as $crate::kem::arrayref::Kem<$ek, $dk, $ct, $ss, $rand_kg, $rand_encaps>>::decaps(ss, ct, dk).map_err($crate::kem::slice::DecapsError::from)
<$type as $crate::kem::arrayref::Kem<$ek, $dk, $ct, $ss, $rand_kg, $rand_encaps>>::decaps(ss, ct, dk)
.map_err(|_| $crate::kem::slice::DecapsError::Unknown)
}

}
Expand Down