digest: add implementations of the AssociatedOid trait

.github/workflows/digest.yml

@@ -68,4 +68,5 @@ jobs:
       - run: cargo test --features dev
       - run: cargo test --features alloc
       - run: cargo test --features std
-      - run: cargo test --all-features
+      # the `oid` feature bumps MSRV to 1.57
+      # - run: cargo test --all-features

digest/CHANGELOG.md

@@ -5,6 +5,13 @@ 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).
 
+## UNRELEASED
+### Added
+- Feature-gated implementation of the `const_oid::AssociatedOid` trait
+for the core wrappers. ([#1098])
+
+[#1098]: https://github.com/RustCrypto/traits/pull/1098
+
 ## 0.10.3 (2022-02-16)
 ### Fixed
 - Minimal versions build ([#940])

digest/Cargo.toml

@@ -18,12 +18,16 @@ crypto-common = { version = "0.1.3", path = "../crypto-common" }
 block-buffer = { version = "0.10", optional = true }
 subtle = { version = "=2.4", default-features = false, optional = true }
 blobby = { version = "0.3", optional = true }
+# Enable implementation of the `AssociatedOid` trait for the core wrappers.
+# Enabling this feature bumps MSRV to 1.57.
+const-oid = { version = "0.9", optional = true }
 
 [features]
 default = ["core-api"]
 core-api = ["block-buffer"] # Enable Core API traits
 mac = ["subtle"] # Enable MAC traits
 rand_core = ["crypto-common/rand_core"] # Enable random key generation methods
+oid = ["const-oid"] # OID support
 alloc = []
 std = ["alloc", "crypto-common/std"]
 dev = ["blobby"]

digest/src/core_api/ct_variable.rs

@@ -5,17 +5,24 @@ use super::{
 use crate::HashMarker;
 #[cfg(feature = "mac")]
 use crate::MacMarker;
+#[cfg(feature = "oid")]
+use const_oid::{AssociatedOid, ObjectIdentifier};
 use core::{fmt, marker::PhantomData};
 use crypto_common::{
     generic_array::{ArrayLength, GenericArray},
     typenum::{IsLess, IsLessOrEqual, Le, LeEq, NonZero, U256},
     Block, BlockSizeUser, OutputSizeUser,
 };
 
+/// Dummy type used with [`CtVariableCoreWrapper`] in cases when
+/// resulting hash does not have a known OID.
+#[derive(Copy, Clone, Debug, Eq, PartialEq, Hash)]
+pub struct NoOid;
+
 /// Wrapper around [`VariableOutputCore`] which selects output size
 /// at compile time.
 #[derive(Clone)]
-pub struct CtVariableCoreWrapper<T, OutSize>
+pub struct CtVariableCoreWrapper<T, OutSize, O = NoOid>
 where
     T: VariableOutputCore,
     OutSize: ArrayLength<u8> + IsLessOrEqual<T::OutputSize>,
@@ -24,10 +31,10 @@ where
     Le<T::BlockSize, U256>: NonZero,
 {
     inner: T,
-    _out: PhantomData<OutSize>,
+    _out: PhantomData<(OutSize, O)>,
 }
 
-impl<T, OutSize> HashMarker for CtVariableCoreWrapper<T, OutSize>
+impl<T, OutSize, O> HashMarker for CtVariableCoreWrapper<T, OutSize, O>
 where
     T: VariableOutputCore + HashMarker,
     OutSize: ArrayLength<u8> + IsLessOrEqual<T::OutputSize>,
@@ -38,7 +45,7 @@ where
 }
 
 #[cfg(feature = "mac")]
-impl<T, OutSize> MacMarker for CtVariableCoreWrapper<T, OutSize>
+impl<T, OutSize, O> MacMarker for CtVariableCoreWrapper<T, OutSize, O>
 where
     T: VariableOutputCore + MacMarker,
     OutSize: ArrayLength<u8> + IsLessOrEqual<T::OutputSize>,
@@ -48,7 +55,7 @@ where
 {
 }
 
-impl<T, OutSize> BlockSizeUser for CtVariableCoreWrapper<T, OutSize>
+impl<T, OutSize, O> BlockSizeUser for CtVariableCoreWrapper<T, OutSize, O>
 where
     T: VariableOutputCore,
     OutSize: ArrayLength<u8> + IsLessOrEqual<T::OutputSize>,
@@ -59,7 +66,7 @@ where
     type BlockSize = T::BlockSize;
 }
 
-impl<T, OutSize> UpdateCore for CtVariableCoreWrapper<T, OutSize>
+impl<T, OutSize, O> UpdateCore for CtVariableCoreWrapper<T, OutSize, O>
 where
     T: VariableOutputCore,
     OutSize: ArrayLength<u8> + IsLessOrEqual<T::OutputSize>,
@@ -73,7 +80,7 @@ where
     }
 }
 
-impl<T, OutSize> OutputSizeUser for CtVariableCoreWrapper<T, OutSize>
+impl<T, OutSize, O> OutputSizeUser for CtVariableCoreWrapper<T, OutSize, O>
 where
     T: VariableOutputCore,
     OutSize: ArrayLength<u8> + IsLessOrEqual<T::OutputSize> + 'static,
@@ -84,7 +91,7 @@ where
     type OutputSize = OutSize;
 }
 
-impl<T, OutSize> BufferKindUser for CtVariableCoreWrapper<T, OutSize>
+impl<T, OutSize, O> BufferKindUser for CtVariableCoreWrapper<T, OutSize, O>
 where
     T: VariableOutputCore,
     OutSize: ArrayLength<u8> + IsLessOrEqual<T::OutputSize>,
@@ -95,7 +102,7 @@ where
     type BufferKind = T::BufferKind;
 }
 
-impl<T, OutSize> FixedOutputCore for CtVariableCoreWrapper<T, OutSize>
+impl<T, OutSize, O> FixedOutputCore for CtVariableCoreWrapper<T, OutSize, O>
 where
     T: VariableOutputCore,
     OutSize: ArrayLength<u8> + IsLessOrEqual<T::OutputSize> + 'static,
@@ -120,7 +127,7 @@ where
     }
 }
 
-impl<T, OutSize> Default for CtVariableCoreWrapper<T, OutSize>
+impl<T, OutSize, O> Default for CtVariableCoreWrapper<T, OutSize, O>
 where
     T: VariableOutputCore,
     OutSize: ArrayLength<u8> + IsLessOrEqual<T::OutputSize>,
@@ -137,7 +144,7 @@ where
     }
 }
 
-impl<T, OutSize> Reset for CtVariableCoreWrapper<T, OutSize>
+impl<T, OutSize, O> Reset for CtVariableCoreWrapper<T, OutSize, O>
 where
     T: VariableOutputCore,
     OutSize: ArrayLength<u8> + IsLessOrEqual<T::OutputSize>,
@@ -151,7 +158,7 @@ where
     }
 }
 
-impl<T, OutSize> AlgorithmName for CtVariableCoreWrapper<T, OutSize>
+impl<T, OutSize, O> AlgorithmName for CtVariableCoreWrapper<T, OutSize, O>
 where
     T: VariableOutputCore + AlgorithmName,
     OutSize: ArrayLength<u8> + IsLessOrEqual<T::OutputSize>,
@@ -165,3 +172,33 @@ where
         write!(f, "{}", OutSize::USIZE)
     }
 }
+
+#[cfg(feature = "oid")]
+#[cfg_attr(docsrs, doc(cfg(feature = "oid")))]
+impl<T, OutSize, O> AssociatedOid for CtVariableCoreWrapper<T, OutSize, O>
+where
+    T: VariableOutputCore,
+    O: AssociatedOid,
+    OutSize: ArrayLength<u8> + IsLessOrEqual<T::OutputSize>,
+    LeEq<OutSize, T::OutputSize>: NonZero,
+    T::BlockSize: IsLess<U256>,
+    Le<T::BlockSize, U256>: NonZero,
+{
+    const OID: ObjectIdentifier = O::OID;
+}
+
+/// Implement dummy type with hidden docs which is used to "carry" hasher
+/// OID for [`CtVariableCoreWrapper`].
+#[macro_export]
+macro_rules! impl_oid_carrier {
+    ($name:ident, $oid:literal) => {
+        #[doc(hidden)]
+        #[derive(Copy, Clone, Debug, Eq, PartialEq, Hash)]
+        pub struct $name;
+
+        #[cfg(feature = "oid")]
+        impl AssociatedOid for $name {
+            const OID: ObjectIdentifier = ObjectIdentifier::new_unwrap($oid);
+        }
+    };
+}

digest/src/core_api/wrapper.rs

@@ -14,6 +14,8 @@ use crypto_common::{
 
 #[cfg(feature = "mac")]
 use crate::MacMarker;
+#[cfg(feature = "oid")]
+use const_oid::{AssociatedOid, ObjectIdentifier};
 
 /// Wrapper around [`BufferKindUser`].
 ///
@@ -227,6 +229,17 @@ where
     }
 }
 
+#[cfg(feature = "oid")]
+#[cfg_attr(docsrs, doc(cfg(feature = "oid")))]
+impl<T> AssociatedOid for CoreWrapper<T>
+where
+    T: BufferKindUser + AssociatedOid,
+    T::BlockSize: IsLess<U256>,
+    Le<T::BlockSize, U256>: NonZero,
+{
+    const OID: ObjectIdentifier = T::OID;
+}
+
 #[cfg(feature = "std")]
 #[cfg_attr(docsrs, doc(cfg(feature = "std")))]
 impl<T> std::io::Write for CoreWrapper<T>

digest/src/lib.rs

@@ -60,6 +60,9 @@ mod mac;
 #[cfg(feature = "core-api")]
 #[cfg_attr(docsrs, doc(cfg(feature = "core-api")))]
 pub use block_buffer;
+#[cfg(feature = "oid")]
+#[cfg_attr(docsrs, doc(cfg(feature = "oid")))]
+pub use const_oid;
 pub use crypto_common;
 
 pub use crate::digest::{Digest, DynDigest, HashMarker};