jh: implement SerializableState

jh/CHANGELOG.md

@@ -5,6 +5,12 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## 0.2.1 (UNRELEASED)
+### Changed
+- Implementation of the `SerializableState` trait ([#889])
+
+[#889]: https://github.com/RustCrypto/hashes/pull/889
+
 ## 0.2.0 (2026-03-27)
 ### Added
 - `alloc` crate feature ([#678])

jh/src/block_api.rs

@@ -6,7 +6,8 @@ use digest::{
         AlgorithmName, Block, BlockSizeUser, Buffer, BufferKindUser, Eager, OutputSizeUser,
         TruncSide, UpdateCore, VariableOutputCore,
     },
-    typenum::{U64, Unsigned},
+    common::hazmat::{DeserializeStateError, SerializableState, SerializedState},
+    typenum::{U64, U128, U136, Unsigned},
 };
 
 use crate::consts;
@@ -89,6 +90,33 @@ impl fmt::Debug for JhCore {
     }
 }
 
+impl SerializableState for JhCore {
+    type SerializedStateSize = U136;
+
+    #[inline]
+    fn serialize(&self) -> SerializedState<Self> {
+        let mut serialized_state = SerializedState::<Self>::default();
+        let (state_dst, block_len_dst) = serialized_state.split_at_mut(128);
+
+        state_dst.copy_from_slice(self.state.finalize());
+        block_len_dst.copy_from_slice(&self.block_len.to_le_bytes());
+
+        serialized_state
+    }
+
+    #[inline]
+    fn deserialize(
+        serialized_state: &SerializedState<Self>,
+    ) -> Result<Self, DeserializeStateError> {
+        let (serialized_state, serialized_block_len) = serialized_state.split::<U128>();
+
+        Ok(Self {
+            state: Compressor::new(serialized_state.0),
+            block_len: u64::from_le_bytes(serialized_block_len.0),
+        })
+    }
+}
+
 impl Drop for JhCore {
     fn drop(&mut self) {
         #[cfg(feature = "zeroize")]

jh/src/lib.rs

@@ -22,20 +22,20 @@ use digest::{
 digest::buffer_fixed!(
     /// JH-224 hasher.
     pub struct Jh224(CtOutWrapper<block_api::JhCore, U28>);
-    impl: BaseFixedTraits AlgorithmName Default Clone HashMarker Reset FixedOutputReset;
+    impl: FixedHashTraits;
 );
 digest::buffer_fixed!(
     /// JH-256 hasher.
     pub struct Jh256(CtOutWrapper<block_api::JhCore, U32>);
-    impl: BaseFixedTraits AlgorithmName Default Clone HashMarker Reset FixedOutputReset;
+    impl: FixedHashTraits;
 );
 digest::buffer_fixed!(
     /// JH-384 hasher.
     pub struct Jh384(CtOutWrapper<block_api::JhCore, U48>);
-    impl: BaseFixedTraits AlgorithmName Default Clone HashMarker Reset FixedOutputReset;
+    impl: FixedHashTraits;
 );
 digest::buffer_fixed!(
     /// JH-512 hasher.
     pub struct Jh512(CtOutWrapper<block_api::JhCore, U64>);
-    impl: BaseFixedTraits AlgorithmName Default Clone HashMarker Reset FixedOutputReset;
+    impl: FixedHashTraits;
 );

jh/tests/mod.rs

@@ -1,4 +1,4 @@
-use digest::{dev::fixed_test, new_test};
+use digest::{dev::fixed_test, hash_serialization_test, new_test};
 
 new_test!(jh224_long_kat, jh::Jh224, fixed_test);
 new_test!(jh256_long_kat, jh::Jh256, fixed_test);
@@ -9,3 +9,8 @@ new_test!(jh224_short_kat, jh::Jh224, fixed_test);
 new_test!(jh256_short_kat, jh::Jh256, fixed_test);
 new_test!(jh384_short_kat, jh::Jh384, fixed_test);
 new_test!(jh512_short_kat, jh::Jh512, fixed_test);
+
+hash_serialization_test!(jh224_serialization, jh::Jh224);
+hash_serialization_test!(jh256_serialization, jh::Jh256);
+hash_serialization_test!(jh384_serialization, jh::Jh384);
+hash_serialization_test!(jh512_serialization, jh::Jh512);