Remove serde support (#53)

* Removed serde support

* Removed serde from CI

* Added `serde_impls` removal notice in README

.github/workflows/ci.yml

@@ -49,12 +49,6 @@ jobs:
           RUSTFLAGS: -D warnings -A dead_code -A unused_imports
         run: cargo test --no-default-features --features="p384"
 
-      - name: Run cargo test with X25519 and serde impls enabled
-        env:
-          CARGO_INCREMENTAL: 0
-          RUSTFLAGS: -D warnings -A dead_code -A unused_imports
-        run: cargo test --no-default-features --features="x25519,serde_impls"
-
       - name: Run cargo test with all features enabled
         env:
           CARGO_INCREMENTAL: 0

CHANGELOG.md

@@ -7,6 +7,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ## Pending
 
 * Added `Serializable::write_exact` so serialization requires less stack space
+* Removed all impls of `serde::{Serialize, Deserailize}` from crate
 
 ## [0.11.0] - 2023-10-11
 

Cargo.toml

@@ -19,8 +19,6 @@ default = ["alloc", "p256", "x25519"]
 x25519 = ["dep:x25519-dalek"]
 p384 = ["dep:p384"]
 p256 = ["dep:p256"]
-# Include serde Serialize/Deserialize impls for all relevant types
-serde_impls = ["serde", "generic-array/serde"]
 # Include allocating methods like open() and seal()
 alloc = []
 # Includes an implementation of `std::error::Error` for `HpkeError`. Also does what `alloc` does.
@@ -39,7 +37,6 @@ rand_core = { version = "0.6", default-features = false }
 p256 = { version = "0.13", default-features = false, features = ["arithmetic", "ecdh"], optional = true}
 p384 = { version = "0.13", default-features = false, features = ["arithmetic", "ecdh"], optional = true}
 sha2 = { version = "0.10", default-features = false }
-serde = { version = "1.0", default-features = false, optional = true }
 subtle = { version = "2.5", default-features = false }
 x25519-dalek = { version = "2", default-features = false, features = ["static_secrets"], optional = true }
 zeroize = { version = "1", default-features = false, features = ["zeroize_derive"] }

README.md

@@ -51,7 +51,6 @@ Feature flag list:
 * `x25519` - Enables X25519-based KEMs
 * `p256` - Enables NIST P-256-based KEMs
 * `p384` - Enables NIST P-384-based KEMs
-* `serde_impls` - Includes implementations of `serde::Serialize` and `serde::Deserialize` for all `hpke::Serializable` and `hpke::Deserializable` types
 * `std` - Includes an implementation of `std::error::Error` for `HpkeError`. Also does what `alloc` does.
 
 For info on how to omit or include feature flags, see the [cargo docs on features](https://doc.rust-lang.org/cargo/reference/specifying-dependencies.html#choosing-features).
@@ -61,6 +60,13 @@ Usage Examples
 
 See the [client-server](examples/client_server.rs) example for an idea of how to use HPKE.
 
+Breaking changes
+----------------
+
+### Breaking changes in v0.12
+
+The `serde_impls` feature was removed. If you were using this and require backwards compatible serialization/deserialization, see the wiki page [here](https://github.com/rozbb/rust-hpke/wiki/Migrating-away-from-the-%60serde_impls%60-feature).
+
 MSRV
 ----
 

src/dhkex.rs

@@ -2,9 +2,6 @@ use crate::{kdf::Kdf as KdfTrait, util::KemSuiteId, Deserializable, Serializable
 
 use core::fmt::Debug;
 
-#[cfg(feature = "serde_impls")]
-use serde::{Deserialize as SerdeDeserialize, Serialize as SerdeSerialize};
-
 // This is the maximum value of all of Npk, Ndh, and Nenc. It's achieved by P-521 in RFC 9180 §7.1
 // Table 2.
 pub(crate) const MAX_PUBKEY_SIZE: usize = 133;
@@ -18,37 +15,12 @@ pub struct DhError;
 /// way to generate keypairs, perform the Diffie-Hellman operation, and serialize/deserialize
 /// pubkeys. This is built into a KEM in `kem/dhkem.rs`.
 pub trait DhKeyExchange {
-    // Public and private keys need to implement serde::{Serialize, Deserialize} if the serde_impls
-    // feature is set. So double up all the definitions: one with serde and one without.
-
-    /// The key exchange's public key type. If you want to generate a keypair, see
-    /// `Kem::gen_keypair` or `Kem::derive_keypair`
-    #[cfg(feature = "serde_impls")]
-    type PublicKey: Clone
-        + Debug
-        + PartialEq
-        + Eq
-        + Serializable
-        + Deserializable
-        + SerdeSerialize
-        + for<'a> SerdeDeserialize<'a>;
     /// The key exchange's public key type. If you want to generate a keypair, see
     /// `Kem::gen_keypair` or `Kem::derive_keypair`
-    #[cfg(not(feature = "serde_impls"))]
     type PublicKey: Clone + Debug + PartialEq + Eq + Serializable + Deserializable;
 
     /// The key exchange's private key type. If you want to generate a keypair, see
     /// `Kem::gen_keypair` or `Kem::derive_keypair`
-    #[cfg(feature = "serde_impls")]
-    type PrivateKey: Clone
-        + Serializable
-        + Deserializable
-        + SerdeSerialize
-        + for<'a> SerdeDeserialize<'a>;
-
-    /// The key exchange's private key type. If you want to generate a keypair, see
-    /// `Kem::gen_keypair` or `Kem::derive_keypair`
-    #[cfg(not(feature = "serde_impls"))]
     type PrivateKey: Clone + Serializable + Deserializable;
 
     /// The result of a DH operation

src/kem.rs

@@ -11,57 +11,20 @@ use zeroize::Zeroize;
 mod dhkem;
 pub use dhkem::*;
 
-#[cfg(feature = "serde_impls")]
-use serde::{Deserialize as SerdeDeserialize, Serialize as SerdeSerialize};
-
 /// Represents authenticated encryption functionality
 pub trait Kem: Sized {
     /// The key exchange's public key type. If you want to generate a keypair, see
     /// `Kem::gen_keypair` or `Kem::derive_keypair`
-    #[cfg(feature = "serde_impls")]
-    type PublicKey: Clone
-        + Debug
-        + PartialEq
-        + Eq
-        + Serializable
-        + Deserializable
-        + SerdeSerialize
-        + for<'a> SerdeDeserialize<'a>;
-    /// The key exchange's public key type. If you want to generate a keypair, see
-    /// `Kem::gen_keypair` or `Kem::derive_keypair`
-    #[cfg(not(feature = "serde_impls"))]
     type PublicKey: Clone + Debug + PartialEq + Eq + Serializable + Deserializable;
 
     /// The key exchange's private key type. If you want to generate a keypair, see
     /// `Kem::gen_keypair` or `Kem::derive_keypair`
-    #[cfg(feature = "serde_impls")]
-    type PrivateKey: Clone
-        + PartialEq
-        + Eq
-        + Serializable
-        + Deserializable
-        + SerdeSerialize
-        + for<'a> SerdeDeserialize<'a>;
-
-    /// The key exchange's private key type. If you want to generate a keypair, see
-    /// `Kem::gen_keypair` or `Kem::derive_keypair`
-    #[cfg(not(feature = "serde_impls"))]
     type PrivateKey: Clone + PartialEq + Eq + Serializable + Deserializable;
 
     /// Computes the public key of a given private key
     fn sk_to_pk(sk: &Self::PrivateKey) -> Self::PublicKey;
-
-    /// The encapsulated key for this KEM. This is used by the recipient to derive the shared
-    /// secret.
-    #[cfg(feature = "serde_impls")]
-    type EncappedKey: Clone
-        + Serializable
-        + Deserializable
-        + SerdeSerialize
-        + for<'a> SerdeDeserialize<'a>;
     /// The encapsulated key for this KEM. This is used by the recipient to derive the shared
     /// secret.
-    #[cfg(not(feature = "serde_impls"))]
     type EncappedKey: Clone + Serializable + Deserializable;
 
     /// The size of a shared secret in this KEM

src/lib.rs

@@ -126,9 +126,6 @@ mod op_mode;
 mod setup;
 mod single_shot;
 
-#[cfg(feature = "serde_impls")]
-mod serde_impls;
-
 #[doc(inline)]
 pub use kem::Kem;
 #[doc(inline)]