chore: update copyright headers to SPDX format and code cleanup

- Added VexaHub copyright alongside original Meta copyright
- Replaced verbose license blocks with SPDX-License-Identifier
- Minor code improvements

src/key_exchange/group/curve25519.rs

@@ -1,10 +1,6 @@
+// SPDX-License-Identifier: MIT OR Apache-2.0
+// Copyright (c) VexaHub and contributors.
 // Copyright (c) Meta Platforms, Inc. and affiliates.
-//
-// This source code is dual-licensed under either the MIT license found in the
-// LICENSE-MIT file in the root directory of this source tree or the Apache
-// License, Version 2.0 found in the LICENSE-APACHE file in the root directory
-// of this source tree. You may select, at your option, one of the above-listed
-// licenses.
 
 //! Key Exchange group implementation for Curve25519
 

src/key_exchange/group/ed25519.rs

@@ -1,10 +1,6 @@
+// SPDX-License-Identifier: MIT OR Apache-2.0
+// Copyright (c) VexaHub and contributors.
 // Copyright (c) Meta Platforms, Inc. and affiliates.
-//
-// This source code is dual-licensed under either the MIT license found in the
-// LICENSE-MIT file in the root directory of this source tree or the Apache
-// License, Version 2.0 found in the LICENSE-APACHE file in the root directory
-// of this source tree. You may select, at your option, one of the above-listed
-// licenses.
 
 //! Key Exchange group implementation for Ed25519
 

src/key_exchange/group/elliptic_curve.rs

@@ -1,23 +1,18 @@
+// SPDX-License-Identifier: MIT OR Apache-2.0
+// Copyright (c) VexaHub and contributors.
 // Copyright (c) Meta Platforms, Inc. and affiliates.
-//
-// This source code is dual-licensed under either the MIT license found in the
-// LICENSE-MIT file in the root directory of this source tree or the Apache
-// License, Version 2.0 found in the LICENSE-APACHE file in the root directory
-// of this source tree. You may select, at your option, one of the above-listed
-// licenses.
 
 //! Implementation for EC curves via [`elliptic_curve`] traits.
 
 use core::ops::Mul;
-use digest::OutputSizeUser;
-use digest::block_api::BlockSizeUser;
+
 use elliptic_curve::group::GroupEncoding;
 use elliptic_curve::point::NonIdentity;
 use elliptic_curve::sec1::{ModulusSize, ToSec1Point};
 use elliptic_curve::{
     CurveArithmetic, FieldBytesSize, Generate, NonZeroScalar, ProjectivePoint, Scalar, SecretKey,
 };
-use generic_array::typenum::{IsGreaterOrEqual, IsLess, IsLessOrEqual, Prod, True, U2, U256};
+use generic_array::typenum::U2;
 use generic_array::{ArrayLength, GenericArray};
 use rand::{CryptoRng, Rng};
 use voprf::Mode;
@@ -40,12 +35,6 @@ where
         > + ToSec1Point<Self>,
     // Bounds required by voprf::CipherSuite
     <Self as voprf::Group>::SecurityLevel: Mul<U2>,
-    <<Self as voprf::CipherSuite>::Hash as OutputSizeUser>::OutputSize: ArrayLength
-        + IsLess<U256>
-        + IsLessOrEqual<
-            <<Self as voprf::CipherSuite>::Hash as BlockSizeUser>::BlockSize,
-            Output = True,
-        > + IsGreaterOrEqual<Prod<<Self as voprf::Group>::SecurityLevel, U2>, Output = True>,
 {
     // We don't use `elliptic_curve::PublicKey` because it stores its internals in a
     // format ideal for serialization and not computation. This is inconsistent with
@@ -105,11 +94,8 @@ where
     ProjectivePoint<G>: GroupEncoding<
             Repr = hybrid_array::Array<u8, <FieldBytesSize<G> as ModulusSize>::CompressedPointSize>,
         > + ToSec1Point<G>,
+    // Bounds required by voprf::CipherSuite
     <G as voprf::Group>::SecurityLevel: Mul<U2>,
-    <<G as voprf::CipherSuite>::Hash as OutputSizeUser>::OutputSize: ArrayLength
-        + IsLess<U256>
-        + IsLessOrEqual<<<G as voprf::CipherSuite>::Hash as BlockSizeUser>::BlockSize, Output = True>
-        + IsGreaterOrEqual<Prod<<G as voprf::Group>::SecurityLevel, U2>, Output = True>,
 {
     fn diffie_hellman(
         &self,

src/key_exchange/group/mod.rs

@@ -1,10 +1,6 @@
+// SPDX-License-Identifier: MIT OR Apache-2.0
+// Copyright (c) VexaHub and contributors.
 // Copyright (c) Meta Platforms, Inc. and affiliates.
-//
-// This source code is dual-licensed under either the MIT license found in the
-// LICENSE-MIT file in the root directory of this source tree or the Apache
-// License, Version 2.0 found in the LICENSE-APACHE file in the root directory
-// of this source tree. You may select, at your option, one of the above-listed
-// licenses.
 
 //! Includes the [`Group`] trait and definitions for the key exchange groups
 

src/key_exchange/group/ristretto255.rs

@@ -1,10 +1,6 @@
+// SPDX-License-Identifier: MIT OR Apache-2.0
+// Copyright (c) VexaHub and contributors.
 // Copyright (c) Meta Platforms, Inc. and affiliates.
-//
-// This source code is dual-licensed under either the MIT license found in the
-// LICENSE-MIT file in the root directory of this source tree or the Apache
-// License, Version 2.0 found in the LICENSE-APACHE file in the root directory
-// of this source tree. You may select, at your option, one of the above-listed
-// licenses.
 
 //! Key Exchange group implementation for ristretto255
 

src/key_exchange/mod.rs

@@ -1,10 +1,6 @@
+// SPDX-License-Identifier: MIT OR Apache-2.0
+// Copyright (c) VexaHub and contributors.
 // Copyright (c) Meta Platforms, Inc. and affiliates.
-//
-// This source code is dual-licensed under either the MIT license found in the
-// LICENSE-MIT file in the root directory of this source tree or the Apache
-// License, Version 2.0 found in the LICENSE-APACHE file in the root directory
-// of this source tree. You may select, at your option, one of the above-listed
-// licenses.
 
 //! Includes instantiations of key exchange protocols used in the login step for
 //! OPAQUE
@@ -22,7 +18,6 @@ use core::ops::Add;
 use derive_where::derive_where;
 use digest::Output;
 use digest::block_api::{CoreProxy, SmallBlockSizeUser};
-use generic_array::sequence::Concat;
 use generic_array::typenum::{IsLess, Le, NonZero, Sum, U2, U256};
 use generic_array::{ArrayLength, GenericArray};
 use hybrid_array::Array;
@@ -39,7 +34,7 @@ use crate::key_exchange::group::Group;
 use crate::key_exchange::shared::{NonceLen, STR_CONTEXT};
 use crate::keypair::{PrivateKey, PublicKey};
 use crate::opaque::{Identifiers, MaskedResponse, MaskedResponseLen};
-use crate::serialization::{SliceExt, i2osp};
+use crate::serialization::{ConcatExt, SliceExt, i2osp};
 
 /// The key exchange trait.
 pub trait KeyExchange
@@ -237,10 +232,8 @@ where
         )
         .clone();
 
-        Concat::concat(
-            Concat::concat(elem, self.masking_nonce),
-            self.masked_response.serialize(),
-        )
+        elem.cat(self.masking_nonce)
+            .cat(self.masked_response.serialize())
     }
 }
 

src/key_exchange/shared.rs

@@ -1,17 +1,12 @@
+// SPDX-License-Identifier: MIT OR Apache-2.0
+// Copyright (c) VexaHub and contributors.
 // Copyright (c) Meta Platforms, Inc. and affiliates.
-//
-// This source code is dual-licensed under either the MIT license found in the
-// LICENSE-MIT file in the root directory of this source tree or the Apache
-// License, Version 2.0 found in the LICENSE-APACHE file in the root directory
-// of this source tree. You may select, at your option, one of the above-listed
-// licenses.
 
 use core::ops::Add;
 
 use derive_where::derive_where;
 use digest::block_api::{CoreProxy, SmallBlockSizeUser};
 use digest::{Digest, Mac, Output, OutputSizeUser, Update};
-use generic_array::sequence::Concat;
 use generic_array::typenum::{IsLess, Le, NonZero, Sum, U1, U2, U32, U256, Unsigned};
 use generic_array::{ArrayLength, GenericArray};
 use hkdf::SimpleHkdf as Hkdf;
@@ -28,7 +23,7 @@ use crate::errors::{InternalError, ProtocolError};
 use crate::hash::{Hash, OutputSize, ProxyHash};
 use crate::key_exchange::group::Group;
 use crate::keypair::{KeyPair, PrivateKey, PublicKey};
-use crate::serialization::{SliceExt, UpdateExt, i2osp};
+use crate::serialization::{SliceExt, UpdateExt, i2osp, ConcatExt};
 
 ///////////////
 // Constants //
@@ -421,9 +416,7 @@ where
     type Len = Sum<G::SkLen, NonceLen>;
 
     fn serialize(&self) -> GenericArray<u8, Self::Len> {
-        let a = self.client_e_sk.serialize();
-
-        GenericArray::concat(a, self.client_nonce)
+        self.client_e_sk.serialize().cat(self.client_nonce)
     }
 }
 
@@ -445,7 +438,7 @@ where
     type Len = Sum<NonceLen, G::PkLen>;
 
     fn serialize(&self) -> GenericArray<u8, Self::Len> {
-        self.client_nonce.concat(self.client_e_pk.serialize())
+        self.client_nonce.cat(self.client_e_pk.serialize())
     }
 }
 
@@ -490,6 +483,6 @@ where
     Ke1MessageIterLen<G>: ArrayLength,
 {
     pub(crate) fn serialize(&self) -> GenericArray<u8, Ke1MessageIterLen<G>> {
-        self.client_nonce.concat(self.client_e_pk.clone())
+        self.client_nonce.cat(self.client_e_pk.clone())
     }
 }

src/key_exchange/sigma_i/ecdsa.rs

@@ -1,10 +1,6 @@
+// SPDX-License-Identifier: MIT OR Apache-2.0
+// Copyright (c) VexaHub and contributors.
 // Copyright (c) Meta Platforms, Inc. and affiliates.
-//
-// This source code is dual-licensed under either the MIT license found in the
-// LICENSE-MIT file in the root directory of this source tree or the Apache
-// License, Version 2.0 found in the LICENSE-APACHE file in the root directory
-// of this source tree. You may select, at your option, one of the above-listed
-// licenses.
 
 //! ECDSA implementation for [`elliptic_curve`] [`Group`] implementations to
 //! support [`SigmaI`](crate::SigmaI).

src/key_exchange/sigma_i/hash_eddsa.rs

@@ -1,10 +1,6 @@
+// SPDX-License-Identifier: MIT OR Apache-2.0
+// Copyright (c) VexaHub and contributors.
 // Copyright (c) Meta Platforms, Inc. and affiliates.
-//
-// This source code is dual-licensed under either the MIT license found in the
-// LICENSE-MIT file in the root directory of this source tree or the Apache
-// License, Version 2.0 found in the LICENSE-APACHE file in the root directory
-// of this source tree. You may select, at your option, one of the above-listed
-// licenses.
 
 //! HashEdDSA implementation for [`SigmaI`](crate::SigmaI). Currently only
 //! supports [`Ed25519`](crate::Ed25519).

src/key_exchange/sigma_i/message.rs

@@ -1,10 +1,6 @@
+// SPDX-License-Identifier: MIT OR Apache-2.0
+// Copyright (c) VexaHub and contributors.
 // Copyright (c) Meta Platforms, Inc. and affiliates.
-//
-// This source code is dual-licensed under either the MIT license found in the
-// LICENSE-MIT file in the root directory of this source tree or the Apache
-// License, Version 2.0 found in the LICENSE-APACHE file in the root directory
-// of this source tree. You may select, at your option, one of the above-listed
-// licenses.
 
 use core::ops::Add;
 

src/key_exchange/sigma_i/mod.rs

@@ -1,10 +1,6 @@
+// SPDX-License-Identifier: MIT OR Apache-2.0
+// Copyright (c) VexaHub and contributors.
 // Copyright (c) Meta Platforms, Inc. and affiliates.
-//
-// This source code is dual-licensed under either the MIT license found in the
-// LICENSE-MIT file in the root directory of this source tree or the Apache
-// License, Version 2.0 found in the LICENSE-APACHE file in the root directory
-// of this source tree. You may select, at your option, one of the above-listed
-// licenses.
 
 //! An implementation of the SIGMA-I key exchange protocol
 //!
@@ -25,7 +21,6 @@ use core::ops::Add;
 use derive_where::derive_where;
 use digest::block_api::{BlockSizeUser, CoreProxy, SmallBlockSizeUser};
 use digest::{Mac, Output, OutputSizeUser};
-use generic_array::sequence::Concat;
 use generic_array::typenum::{IsLess, Le, NonZero, Sum, U256};
 use generic_array::{ArrayLength, GenericArray};
 use hmac::{KeyInit, SimpleHmac};
@@ -521,16 +516,11 @@ where
     type Len = Ke2StateLen<CS, SIG, KE>;
 
     fn serialize(&self) -> GenericArray<u8, Self::Len> {
-        Concat::concat(
-            Concat::concat(
-                Concat::concat(
-                    self.client_s_pk.serialize(),
-                    GenericArray::from_slice(self.session_key.as_slice()).clone(),
-                ),
-                self.verify_state.serialize(),
-            ),
-            GenericArray::from_slice(self.expected_mac.as_slice()).clone(),
-        )
+        self.client_s_pk
+            .serialize()
+            .cat(GenericArray::from_slice(self.session_key.as_slice()).clone())
+            .cat(self.verify_state.serialize())
+            .cat(GenericArray::from_slice(self.expected_mac.as_slice()).clone())
     }
 }
 
@@ -601,9 +591,7 @@ where
     type Len = Sum<SIG::SignatureLen, OutputSize<KEH>>;
 
     fn serialize(&self) -> GenericArray<u8, Self::Len> {
-        Concat::concat(
-            SIG::serialize_signature(&self.signature),
-            GenericArray::from_slice(self.mac.as_slice()).clone(),
-        )
+        SIG::serialize_signature(&self.signature)
+            .cat(GenericArray::from_slice(self.mac.as_slice()).clone())
     }
 }

src/key_exchange/sigma_i/pure_eddsa.rs

@@ -1,10 +1,6 @@
+// SPDX-License-Identifier: MIT OR Apache-2.0
+// Copyright (c) VexaHub and contributors.
 // Copyright (c) Meta Platforms, Inc. and affiliates.
-//
-// This source code is dual-licensed under either the MIT license found in the
-// LICENSE-MIT file in the root directory of this source tree or the Apache
-// License, Version 2.0 found in the LICENSE-APACHE file in the root directory
-// of this source tree. You may select, at your option, one of the above-listed
-// licenses.
 
 //! PureEdDSA implementation for [`SigmaI`](crate::SigmaI). Currently only
 //! supports [`Ed25519`](crate::Ed25519).

src/key_exchange/sigma_i/shared.rs

@@ -1,10 +1,6 @@
+// SPDX-License-Identifier: MIT OR Apache-2.0
+// Copyright (c) VexaHub and contributors.
 // Copyright (c) Meta Platforms, Inc. and affiliates.
-//
-// This source code is dual-licensed under either the MIT license found in the
-// LICENSE-MIT file in the root directory of this source tree or the Apache
-// License, Version 2.0 found in the LICENSE-APACHE file in the root directory
-// of this source tree. You may select, at your option, one of the above-listed
-// licenses.
 
 use derive_where::derive_where;
 use digest::{Output, OutputSizeUser};

src/key_exchange/tripledh.rs

@@ -1,10 +1,6 @@
+// SPDX-License-Identifier: MIT OR Apache-2.0
+// Copyright (c) VexaHub and contributors.
 // Copyright (c) Meta Platforms, Inc. and affiliates.
-//
-// This source code is dual-licensed under either the MIT license found in the
-// LICENSE-MIT file in the root directory of this source tree or the Apache
-// License, Version 2.0 found in the LICENSE-APACHE file in the root directory
-// of this source tree. You may select, at your option, one of the above-listed
-// licenses.
 
 //! An implementation of the Triple Diffie-Hellman key exchange protocol
 

src/key_exchange/tripledh_kem.rs

@@ -1,10 +1,6 @@
+// SPDX-License-Identifier: MIT OR Apache-2.0
+// Copyright (c) VexaHub and contributors.
 // Copyright (c) Meta Platforms, Inc. and affiliates.
-//
-// This source code is dual-licensed under either the MIT license found in the
-// LICENSE-MIT file in the root directory of this source tree or the Apache
-// License, Version 2.0 found in the LICENSE-APACHE file in the root directory
-// of this source tree. You may select, at your option, one of the above-listed
-// licenses.
 
 //! TripleDH-KEM is a variant of the OPAQUE Triple Diffie-Hellman handshake in
 //! which the client supplies a KEM public key in KE1 and the server performs a