digest: add XofFixedWrapper (#1815)

Author: daxpedda

digest/src/lib.rs

@@ -55,6 +55,7 @@ pub mod core_api;
 mod digest;
 #[cfg(feature = "mac")]
 mod mac;
+mod xof_fixed;
 
 #[cfg(feature = "core-api")]
 pub use block_buffer;
@@ -70,6 +71,7 @@ pub use crypto_common::{InnerInit, InvalidLength, Key, KeyInit};
 pub use crypto_common::{Output, OutputSizeUser, Reset, array, typenum, typenum::consts};
 #[cfg(feature = "mac")]
 pub use mac::{CtOutput, Mac, MacError, MacMarker};
+pub use xof_fixed::XofFixedWrapper;
 
 use core::fmt;
 

digest/src/xof_fixed.rs

@@ -0,0 +1,146 @@
+use core::fmt;
+use core::marker::PhantomData;
+
+use crypto_common::array::ArraySize;
+use crypto_common::hazmat::SerializableState;
+use crypto_common::{BlockSizeUser, KeyInit, KeySizeUser, OutputSizeUser, Reset};
+
+use crate::{
+    CustomizedInit, ExtendableOutput, ExtendableOutputReset, FixedOutput, FixedOutputReset,
+    HashMarker, Update,
+};
+
+/// Wrapper around [`ExtendableOutput`] types adding [`OutputSizeUser`] with the given size of `S`.
+pub struct XofFixedWrapper<T: ExtendableOutput, S: ArraySize> {
+    hash: T,
+    size: PhantomData<S>,
+}
+
+impl<T: ExtendableOutput + Clone, S: ArraySize> Clone for XofFixedWrapper<T, S> {
+    fn clone(&self) -> Self {
+        Self {
+            hash: self.hash.clone(),
+            size: PhantomData,
+        }
+    }
+}
+
+impl<T: ExtendableOutput + fmt::Debug, S: ArraySize> fmt::Debug for XofFixedWrapper<T, S> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.debug_struct("XofFixedWrapper")
+            .field("hash", &self.hash)
+            .field("_size", &self.size)
+            .finish()
+    }
+}
+
+impl<T: ExtendableOutput + Default, S: ArraySize> Default for XofFixedWrapper<T, S> {
+    fn default() -> Self {
+        Self {
+            hash: Default::default(),
+            size: PhantomData,
+        }
+    }
+}
+
+impl<T: ExtendableOutput + HashMarker, S: ArraySize> HashMarker for XofFixedWrapper<T, S> {}
+
+#[cfg(feature = "mac")]
+impl<T: ExtendableOutput + crate::MacMarker, S: ArraySize> crate::MacMarker
+    for XofFixedWrapper<T, S>
+{
+}
+
+// this blanket impl is needed for HMAC
+impl<T: ExtendableOutput + BlockSizeUser, S: ArraySize> BlockSizeUser for XofFixedWrapper<T, S> {
+    type BlockSize = T::BlockSize;
+}
+
+impl<T: ExtendableOutput + KeySizeUser, S: ArraySize> KeySizeUser for XofFixedWrapper<T, S> {
+    type KeySize = T::KeySize;
+}
+
+impl<T: ExtendableOutput + KeyInit, S: ArraySize> KeyInit for XofFixedWrapper<T, S> {
+    fn new(key: &crypto_common::Key<Self>) -> Self {
+        Self {
+            hash: T::new(key),
+            size: PhantomData,
+        }
+    }
+}
+
+impl<T: ExtendableOutput + Reset, S: ArraySize> Reset for XofFixedWrapper<T, S> {
+    fn reset(&mut self) {
+        self.hash.reset();
+    }
+}
+
+impl<T: ExtendableOutput + Update, S: ArraySize> Update for XofFixedWrapper<T, S> {
+    fn update(&mut self, data: &[u8]) {
+        self.hash.update(data)
+    }
+}
+
+impl<T: ExtendableOutput, S: ArraySize> OutputSizeUser for XofFixedWrapper<T, S> {
+    type OutputSize = S;
+}
+
+impl<T: ExtendableOutput + Update, S: ArraySize> FixedOutput for XofFixedWrapper<T, S> {
+    fn finalize_into(self, out: &mut crypto_common::Output<Self>) {
+        self.hash.finalize_xof_into(out);
+    }
+}
+
+impl<T: ExtendableOutputReset, S: ArraySize> FixedOutputReset for XofFixedWrapper<T, S> {
+    fn finalize_into_reset(&mut self, out: &mut crypto_common::Output<Self>) {
+        self.hash.finalize_xof_reset_into(out);
+    }
+}
+
+impl<T: ExtendableOutput, S: ArraySize> ExtendableOutput for XofFixedWrapper<T, S> {
+    type Reader = T::Reader;
+
+    fn finalize_xof(self) -> Self::Reader {
+        self.hash.finalize_xof()
+    }
+}
+
+impl<T: ExtendableOutputReset, S: ArraySize> ExtendableOutputReset for XofFixedWrapper<T, S> {
+    fn finalize_xof_reset(&mut self) -> Self::Reader {
+        self.hash.finalize_xof_reset()
+    }
+}
+
+#[cfg(feature = "zeroize")]
+impl<T: ExtendableOutput + zeroize::ZeroizeOnDrop, S: ArraySize> zeroize::ZeroizeOnDrop
+    for XofFixedWrapper<T, S>
+{
+}
+
+impl<T: ExtendableOutput + CustomizedInit, S: ArraySize> CustomizedInit for XofFixedWrapper<T, S> {
+    fn new_customized(customization: &[u8]) -> Self {
+        Self {
+            hash: T::new_customized(customization),
+            size: PhantomData,
+        }
+    }
+}
+
+impl<T: ExtendableOutput + SerializableState, S: ArraySize> SerializableState
+    for XofFixedWrapper<T, S>
+{
+    type SerializedStateSize = T::SerializedStateSize;
+
+    fn serialize(&self) -> crypto_common::hazmat::SerializedState<Self> {
+        self.hash.serialize()
+    }
+
+    fn deserialize(
+        serialized_state: &crypto_common::hazmat::SerializedState<Self>,
+    ) -> Result<Self, crypto_common::hazmat::DeserializeStateError> {
+        T::deserialize(serialized_state).map(|hash| Self {
+            hash,
+            size: PhantomData,
+        })
+    }
+}