diff --git a/digest/src/lib.rs b/digest/src/lib.rs
index 79bef801d..1d005d15f 100644
--- a/digest/src/lib.rs
+++ b/digest/src/lib.rs
@@ -79,8 +79,59 @@ pub trait FixedOutput {
     /// Output size for fixed output digest
     type OutputSize: ArrayLength<u8>;
 
-    /// Retrieve result and consume hasher instance.
-    fn finalize_fixed(self) -> GenericArray<u8, Self::OutputSize>;
+    /// Write result into provided array and consume the hasher instance.
+    fn finalize_into(self, out: &mut GenericArray<u8, Self::OutputSize>);
+
+    /// Write result into provided array and reset the hasher instance.
+    fn finalize_into_reset(&mut self, out: &mut GenericArray<u8, Self::OutputSize>);
+
+    /// Retrieve result and consume the hasher instance.
+    #[inline]
+    fn finalize_fixed(self) -> GenericArray<u8, Self::OutputSize>
+    where
+        Self: Sized
+    {
+        let mut out = Default::default();
+        self.finalize_into(&mut out);
+        out
+    }
+
+    /// Retrieve result and reset the hasher instance.
+    #[inline]
+    fn finalize_fixed_reset(&mut self) -> GenericArray<u8, Self::OutputSize> {
+        let mut out = Default::default();
+        self.finalize_into_reset(&mut out);
+        out
+    }
+}
+
+/// Trait for fixed-output digest implementations to use to retrieve the
+/// hash output.
+pub trait FixedOutputDirty {
+    /// Output size for fixed output digest
+    type OutputSize: ArrayLength<u8>;
+
+    /// Retrieve result into provided buffer and leave hasher in a dirty state.
+    /// Usage of this method in user code is discouraged, prefer `finalize_fixed`
+    /// or `finalize_fixed_reset`.
+    ///
+    /// Implementations should panic if this is called twice without resetting.
+    fn finalize_into_dirty(&mut self, out: &mut GenericArray<u8, Self::OutputSize>);
+}
+
+impl<D: FixedOutputDirty + Reset> FixedOutput for D {
+    type OutputSize = D::OutputSize;
+
+    #[inline]
+    fn finalize_into(mut self, out: &mut GenericArray<u8, Self::OutputSize>) {
+        self.finalize_into_dirty(out);
+    }
+
+    #[inline]
+    fn finalize_into_reset(&mut self, out: &mut GenericArray<u8, Self::OutputSize>) {
+        self.finalize_into_dirty(out);
+        self.reset();
+    }
 }
 
 /// Trait for returning digest result with the variable size