diff --git a/Cargo.lock b/Cargo.lock
index 78e580899..874fe71da 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -6,7 +6,7 @@ version = 3
 name = "blake2"
 version = "0.10.4"
 dependencies = [
- "digest",
+ "digest 0.10.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "hex-literal",
 ]
 
@@ -56,6 +56,15 @@ dependencies = [
  "typenum",
 ]
 
+[[package]]
+name = "crypto-common"
+version = "0.1.6"
+source = "git+https://github.com/RustCrypto/traits?rev=refs/pull/1078/head#fc5c8f798dbc2671f63b3cebcb50879bf5bd7fae"
+dependencies = [
+ "generic-array",
+ "typenum",
+]
+
 [[package]]
 name = "digest"
 version = "0.10.3"
@@ -64,15 +73,25 @@ checksum = "f2fb860ca6fafa5552fb6d0e816a69c8e49f0908bf524e30a90d97c85892d506"
 dependencies = [
  "blobby",
  "block-buffer",
- "crypto-common",
+ "crypto-common 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "subtle",
 ]
 
+[[package]]
+name = "digest"
+version = "0.10.3"
+source = "git+https://github.com/RustCrypto/traits?rev=refs/pull/1078/head#fc5c8f798dbc2671f63b3cebcb50879bf5bd7fae"
+dependencies = [
+ "blobby",
+ "block-buffer",
+ "crypto-common 0.1.6 (git+https://github.com/RustCrypto/traits?rev=refs/pull/1078/head)",
+]
+
 [[package]]
 name = "fsb"
 version = "0.1.2"
 dependencies = [
- "digest",
+ "digest 0.10.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "hex-literal",
  "whirlpool",
 ]
@@ -91,7 +110,7 @@ dependencies = [
 name = "gost94"
 version = "0.10.2"
 dependencies = [
- "digest",
+ "digest 0.10.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "hex-literal",
 ]
 
@@ -99,7 +118,7 @@ dependencies = [
 name = "groestl"
 version = "0.10.1"
 dependencies = [
- "digest",
+ "digest 0.10.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "hex-literal",
 ]
 
@@ -126,7 +145,7 @@ dependencies = [
 name = "k12"
 version = "0.2.1"
 dependencies = [
- "digest",
+ "digest 0.10.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "hex-literal",
 ]
 
@@ -146,7 +165,7 @@ checksum = "8371e4e5341c3a96db127eb2465ac681ced4c433e01dd0e938adbef26ba93ba5"
 name = "md-5"
 version = "0.10.1"
 dependencies = [
- "digest",
+ "digest 0.10.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "hex-literal",
  "md5-asm",
 ]
@@ -155,7 +174,7 @@ dependencies = [
 name = "md2"
 version = "0.10.1"
 dependencies = [
- "digest",
+ "digest 0.10.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "hex-literal",
 ]
 
@@ -163,7 +182,7 @@ dependencies = [
 name = "md4"
 version = "0.10.1"
 dependencies = [
- "digest",
+ "digest 0.10.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "hex-literal",
 ]
 
@@ -186,7 +205,7 @@ checksum = "dbf0c48bc1d91375ae5c3cd81e3722dff1abcf81a30960240640d223f59fe0e5"
 name = "ripemd"
 version = "0.1.1"
 dependencies = [
- "digest",
+ "digest 0.10.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "hex-literal",
 ]
 
@@ -196,7 +215,7 @@ version = "0.10.1"
 dependencies = [
  "cfg-if",
  "cpufeatures",
- "digest",
+ "digest 0.10.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "hex-literal",
  "sha1-asm",
 ]
@@ -216,7 +235,7 @@ version = "0.10.2"
 dependencies = [
  "cfg-if",
  "cpufeatures",
- "digest",
+ "digest 0.10.3 (git+https://github.com/RustCrypto/traits?rev=refs/pull/1078/head)",
  "hex-literal",
  "sha2-asm",
 ]
@@ -234,7 +253,7 @@ dependencies = [
 name = "sha3"
 version = "0.10.2"
 dependencies = [
- "digest",
+ "digest 0.10.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "hex-literal",
  "keccak",
 ]
@@ -243,7 +262,7 @@ dependencies = [
 name = "shabal"
 version = "0.4.1"
 dependencies = [
- "digest",
+ "digest 0.10.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "hex-literal",
 ]
 
@@ -251,7 +270,7 @@ dependencies = [
 name = "sm3"
 version = "0.4.1"
 dependencies = [
- "digest",
+ "digest 0.10.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "hex-literal",
 ]
 
@@ -259,7 +278,7 @@ dependencies = [
 name = "streebog"
 version = "0.10.1"
 dependencies = [
- "digest",
+ "digest 0.10.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "hex-literal",
 ]
 
@@ -273,7 +292,7 @@ checksum = "6bdef32e8150c2a081110b42772ffe7d7c9032b606bc226c8260fd97e0976601"
 name = "tiger"
 version = "0.2.1"
 dependencies = [
- "digest",
+ "digest 0.10.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "hex-literal",
 ]
 
@@ -293,7 +312,7 @@ checksum = "49874b5167b65d7193b8aba1567f5c7d93d001cafc34600cee003eda787e483f"
 name = "whirlpool"
 version = "0.10.1"
 dependencies = [
- "digest",
+ "digest 0.10.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "hex-literal",
  "whirlpool-asm",
 ]
diff --git a/sha2/Cargo.toml b/sha2/Cargo.toml
index cc4c783c8..adceb06c2 100644
--- a/sha2/Cargo.toml
+++ b/sha2/Cargo.toml
@@ -15,7 +15,7 @@ keywords = ["crypto", "sha2", "hash", "digest"]
 categories = ["cryptography", "no-std"]
 
 [dependencies]
-digest = "0.10.3"
+digest = { git = "https://github.com/RustCrypto/traits", rev = "refs/pull/1078/head" }  # TODO change back to #digest = "0.10.3"
 cfg-if = "1.0"
 sha2-asm = { version = "0.6.1", optional = true }
 
@@ -23,7 +23,7 @@ sha2-asm = { version = "0.6.1", optional = true }
 cpufeatures = "0.2"
 
 [dev-dependencies]
-digest = { version = "0.10.3", features = ["dev"] }
+digest = { git = "https://github.com/RustCrypto/traits", rev = "refs/pull/1078/head", features = ["dev"] }  # TODO change back to #digest = { version = "0.10.3", features = ["dev"] }
 hex-literal = "0.2.2"
 
 [features]
diff --git a/sha2/src/core_api.rs b/sha2/src/core_api.rs
index cfec02a64..c7c9dc604 100644
--- a/sha2/src/core_api.rs
+++ b/sha2/src/core_api.rs
@@ -1,15 +1,37 @@
 use crate::{consts, sha256::compress256, sha512::compress512};
-use core::{fmt, slice::from_ref};
+use core::{
+    convert::{TryFrom, TryInto},
+    fmt,
+    mem::size_of,
+    slice::from_ref,
+};
 use digest::{
     block_buffer::Eager,
     core_api::{
-        AlgorithmName, Block, BlockSizeUser, Buffer, BufferKindUser, OutputSizeUser, TruncSide,
-        UpdateCore, VariableOutputCore,
+        AlgorithmName, Block, BlockSizeUser, Buffer, BufferKindUser, HashCoreSerializableState,
+        OutputSizeUser, TruncSide, UpdateCore, VariableOutputCore,
     },
-    typenum::{Unsigned, U128, U32, U64},
+    generic_array::GenericArray,
+    typenum::{Unsigned, U128, U32, U40, U64, U80},
     HashMarker, InvalidOutputSize, Output,
 };
 
+#[cfg(feature = "std")]
+extern crate std;
+
+/// The error type returned when deserialization of the hash core fails.
+#[derive(Copy, Clone, Eq, PartialEq, Debug)]
+pub struct HashCoreStateDeserializationError;
+
+impl fmt::Display for HashCoreStateDeserializationError {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> Result<(), fmt::Error> {
+        f.write_str("HashCoreStateDeserializationError")
+    }
+}
+
+#[cfg(feature = "std")]
+impl std::error::Error for HashCoreStateDeserializationError {}
+
 /// Core block-level SHA-256 hasher with variable output size.
 ///
 /// Supports initialization only for 28 and 32 byte output sizes,
@@ -82,6 +104,57 @@ impl fmt::Debug for Sha256VarCore {
     }
 }
 
+impl HashCoreSerializableState for Sha256VarCore {
+    type SerializedStateSize = U40;
+}
+
+impl Sha256VarCore {
+    const STATE_SIZE: usize = size_of::<consts::State256>();
+    const STATE_ELEMENT_SIZE: usize = size_of::<u32>();
+}
+
+impl TryFrom<GenericArray<u8, U40>> for Sha256VarCore {
+    type Error = HashCoreStateDeserializationError;
+
+    fn try_from(serialized_state: GenericArray<u8, U40>) -> Result<Self, Self::Error> {
+        let buffer = serialized_state.as_slice();
+
+        let mut state = [0; consts::STATE_LEN];
+        for (i, bytes) in buffer[..Self::STATE_SIZE]
+            .as_ref()
+            .chunks(Self::STATE_ELEMENT_SIZE)
+            .enumerate()
+        {
+            state[i] = u32::from_be_bytes(bytes.try_into().unwrap());
+        }
+
+        let block_len = u64::from_be_bytes(buffer[Self::STATE_SIZE..].as_ref().try_into().unwrap());
+
+        Ok(Self { state, block_len })
+    }
+}
+
+impl From<Sha256VarCore> for GenericArray<u8, U40> {
+    fn from(core: Sha256VarCore) -> Self {
+        let mut serialized_state = Self::default();
+        let buffer = serialized_state.as_mut_slice();
+
+        for (i, bytes) in buffer[..Sha256VarCore::STATE_SIZE]
+            .as_mut()
+            .chunks_mut(Sha256VarCore::STATE_ELEMENT_SIZE)
+            .enumerate()
+        {
+            bytes.copy_from_slice(core.state[i].to_be_bytes().as_slice());
+        }
+
+        buffer[Sha256VarCore::STATE_SIZE..]
+            .as_mut()
+            .copy_from_slice(core.block_len.to_be_bytes().as_slice());
+
+        serialized_state
+    }
+}
+
 /// Core block-level SHA-512 hasher with variable output size.
 ///
 /// Supports initialization only for 28, 32, 48, and 64 byte output sizes,
@@ -155,3 +228,55 @@ impl fmt::Debug for Sha512VarCore {
         f.write_str("Sha512VarCore { ... }")
     }
 }
+
+impl HashCoreSerializableState for Sha512VarCore {
+    type SerializedStateSize = U80;
+}
+
+impl Sha512VarCore {
+    const STATE_SIZE: usize = size_of::<consts::State512>();
+    const STATE_ELEMENT_SIZE: usize = size_of::<u64>();
+}
+
+impl TryFrom<GenericArray<u8, U80>> for Sha512VarCore {
+    type Error = HashCoreStateDeserializationError;
+
+    fn try_from(serialized_state: GenericArray<u8, U80>) -> Result<Self, Self::Error> {
+        let buffer = serialized_state.as_slice();
+
+        let mut state = [0; consts::STATE_LEN];
+        for (i, bytes) in buffer[..Self::STATE_SIZE]
+            .as_ref()
+            .chunks(Self::STATE_ELEMENT_SIZE)
+            .enumerate()
+        {
+            state[i] = u64::from_be_bytes(bytes.try_into().unwrap());
+        }
+
+        let block_len =
+            u128::from_be_bytes(buffer[Self::STATE_SIZE..].as_ref().try_into().unwrap());
+
+        Ok(Self { state, block_len })
+    }
+}
+
+impl From<Sha512VarCore> for GenericArray<u8, U80> {
+    fn from(core: Sha512VarCore) -> Self {
+        let mut serialized_state = Self::default();
+        let buffer = serialized_state.as_mut_slice();
+
+        for (i, bytes) in buffer[..Sha512VarCore::STATE_SIZE]
+            .as_mut()
+            .chunks_mut(Sha512VarCore::STATE_ELEMENT_SIZE)
+            .enumerate()
+        {
+            bytes.copy_from_slice(core.state[i].to_be_bytes().as_slice());
+        }
+
+        buffer[Sha512VarCore::STATE_SIZE..]
+            .as_mut()
+            .copy_from_slice(core.block_len.to_be_bytes().as_slice());
+
+        serialized_state
+    }
+}
diff --git a/sha2/src/lib.rs b/sha2/src/lib.rs
index 6eeec46e0..c1e34228e 100644
--- a/sha2/src/lib.rs
+++ b/sha2/src/lib.rs
@@ -56,7 +56,8 @@ pub use digest::{self, Digest};
 
 use digest::{
     consts::{U28, U32, U48, U64},
-    core_api::{CoreWrapper, CtVariableCoreWrapper},
+    core_api::{CoreWrapper, CtVariableCoreWrapper, HashCoreSerializableState},
+    generic_array::GenericArray,
 };
 
 #[rustfmt::skip]
@@ -72,15 +73,50 @@ pub use sha512::compress512;
 
 pub use core_api::{Sha256VarCore, Sha512VarCore};
 
+/// SHA-224 core.
+pub type Sha224Core = CtVariableCoreWrapper<Sha256VarCore, U28>;
 /// SHA-224 hasher.
-pub type Sha224 = CoreWrapper<CtVariableCoreWrapper<Sha256VarCore, U28>>;
+pub type Sha224 = CoreWrapper<Sha224Core>;
+/// SHA-224 core serialized state.
+pub type Sha224CoreSerializedState =
+    GenericArray<u8, <Sha224Core as HashCoreSerializableState>::SerializedStateSize>;
+
+/// SHA-256 core.
+pub type Sha256Core = CtVariableCoreWrapper<Sha256VarCore, U32>;
 /// SHA-256 hasher.
-pub type Sha256 = CoreWrapper<CtVariableCoreWrapper<Sha256VarCore, U32>>;
-/// SHA-512/224 hasher.
-pub type Sha512_224 = CoreWrapper<CtVariableCoreWrapper<Sha512VarCore, U28>>;
-/// SHA-512/256 hasher.
-pub type Sha512_256 = CoreWrapper<CtVariableCoreWrapper<Sha512VarCore, U32>>;
+pub type Sha256 = CoreWrapper<Sha256Core>;
+/// SHA-256 core serialized state.
+pub type Sha256CoreSerializedState =
+    GenericArray<u8, <Sha256Core as HashCoreSerializableState>::SerializedStateSize>;
+
+/// SHA-512/224 core.
+pub type Sha512_224Core = CtVariableCoreWrapper<Sha512VarCore, U28>;
+/// SHA-512/224 core.
+pub type Sha512_224 = CoreWrapper<Sha512_224Core>;
+/// SHA-512/224 core serialized state.
+pub type Sha512_224CoreSerializedState =
+    GenericArray<u8, <Sha512_224Core as HashCoreSerializableState>::SerializedStateSize>;
+
+/// SHA-512/256 core.
+pub type Sha512_256Core = CtVariableCoreWrapper<Sha512VarCore, U32>;
+/// SHA-512/256 core.
+pub type Sha512_256 = CoreWrapper<Sha512_256Core>;
+/// SHA-512/224 core serialized state.
+pub type Sha512_256CoreSerializedState =
+    GenericArray<u8, <Sha512_256Core as HashCoreSerializableState>::SerializedStateSize>;
+
+/// SHA-384 core.
+pub type Sha384Core = CtVariableCoreWrapper<Sha512VarCore, U48>;
 /// SHA-384 hasher.
-pub type Sha384 = CoreWrapper<CtVariableCoreWrapper<Sha512VarCore, U48>>;
+pub type Sha384 = CoreWrapper<Sha384Core>;
+/// SHA-384 core serialized state.
+pub type Sha384CoreSerializedState =
+    GenericArray<u8, <Sha384Core as HashCoreSerializableState>::SerializedStateSize>;
+
+/// SHA-512 core.
+pub type Sha512Core = CtVariableCoreWrapper<Sha512VarCore, U64>;
 /// SHA-512 hasher.
-pub type Sha512 = CoreWrapper<CtVariableCoreWrapper<Sha512VarCore, U64>>;
+pub type Sha512 = CoreWrapper<Sha512Core>;
+/// SHA-512 core serialized state.
+pub type Sha512CoreSerializedState =
+    GenericArray<u8, <Sha512Core as HashCoreSerializableState>::SerializedStateSize>;
diff --git a/sha2/tests/mod.rs b/sha2/tests/mod.rs
index 91df4683b..ddc566e7c 100644
--- a/sha2/tests/mod.rs
+++ b/sha2/tests/mod.rs
@@ -1,14 +1,63 @@
-use digest::dev::{feed_rand_16mib, fixed_reset_test};
-use digest::new_test;
+use core::convert::TryFrom;
+use digest::{
+    dev::{feed_rand_16mib, fixed_reset_test},
+    new_test, test_internal_state,
+};
 use hex_literal::hex;
-use sha2::{Digest, Sha224, Sha256, Sha384, Sha512, Sha512_224, Sha512_256};
+use sha2::{
+    Digest, Sha224, Sha224Core, Sha224CoreSerializedState, Sha256, Sha256Core,
+    Sha256CoreSerializedState, Sha384, Sha384Core, Sha384CoreSerializedState, Sha512, Sha512Core,
+    Sha512CoreSerializedState, Sha512_224, Sha512_224Core, Sha512_224CoreSerializedState,
+    Sha512_256, Sha512_256Core, Sha512_256CoreSerializedState,
+};
 
 new_test!(sha224_main, "sha224", Sha224, fixed_reset_test);
+test_internal_state!(
+    sha224_internal_state,
+    Sha224,
+    Sha224Core,
+    Sha224CoreSerializedState
+);
+
 new_test!(sha256_main, "sha256", Sha256, fixed_reset_test);
+test_internal_state!(
+    sha256_internal_state,
+    Sha256,
+    Sha256Core,
+    Sha256CoreSerializedState
+);
+
 new_test!(sha512_224_main, "sha512_224", Sha512_224, fixed_reset_test);
+test_internal_state!(
+    sha512_224_internal_state,
+    Sha512_224,
+    Sha512_224Core,
+    Sha512_224CoreSerializedState
+);
+
 new_test!(sha512_256_main, "sha512_256", Sha512_256, fixed_reset_test);
+test_internal_state!(
+    sha512_256_internal_state,
+    Sha512_256,
+    Sha512_256Core,
+    Sha512_256CoreSerializedState
+);
+
 new_test!(sha384_main, "sha384", Sha384, fixed_reset_test);
+test_internal_state!(
+    sha384_internal_state,
+    Sha384,
+    Sha384Core,
+    Sha384CoreSerializedState
+);
+
 new_test!(sha512_main, "sha512", Sha512, fixed_reset_test);
+test_internal_state!(
+    sha512_internal_state,
+    Sha512,
+    Sha512Core,
+    Sha512CoreSerializedState
+);
 
 #[test]
 fn sha256_rand() {