aead: add inout support (#1793)

Renames `AeadInPlaceDetached` to `AeadInOut`, and changes the type
signature so the provided `buffer` is now an `InOutBuf`

Author: tarcieri

Cargo.lock

@@ -23,9 +23,10 @@ arrayvec = { version = "0.7", optional = true, default-features = false }
 blobby = { version = "0.4.0-pre.0", optional = true }
 bytes = { version = "1", optional = true, default-features = false }
 heapless = { version = "0.8", optional = true, default-features = false }
+inout = { version = "0.2.0-rc.4", optional = true, default-features = false }
 
 [features]
-default = ["rand_core"]
+default = ["inout", "rand_core"]
 alloc = []
 dev = ["blobby"]
 os_rng = ["crypto-common/os_rng", "rand_core"]

aead/Cargo.toml

@@ -30,21 +30,26 @@ pub use crypto_common::{
 pub use arrayvec;
 #[cfg(feature = "bytes")]
 pub use bytes;
-#[cfg(feature = "heapless")]
-pub use heapless;
-
 #[cfg(feature = "rand_core")]
 pub use crypto_common::rand_core;
+#[cfg(feature = "heapless")]
+pub use heapless;
+#[cfg(feature = "inout")]
+pub use inout;
 
 use core::fmt;
-use crypto_common::array::{Array, ArraySize, typenum::Unsigned};
+use crypto_common::array::{Array, ArraySize};
 
 #[cfg(feature = "alloc")]
 use alloc::vec::Vec;
 #[cfg(feature = "bytes")]
 use bytes::BytesMut;
+#[cfg(any(feature = "alloc", feature = "inout"))]
+use crypto_common::array::typenum::Unsigned;
 #[cfg(feature = "os_rng")]
 use crypto_common::rand_core::{OsError, OsRng, TryRngCore};
+#[cfg(feature = "inout")]
+use inout::InOutBuf;
 #[cfg(feature = "rand_core")]
 use rand_core::{CryptoRng, TryCryptoRng};
 
@@ -240,23 +245,24 @@ pub trait AeadInPlace: AeadCore {
 }
 
 /// In-place AEAD trait which handles the authentication tag as a return value/separate parameter.
-pub trait AeadInPlaceDetached: AeadCore {
-    /// Encrypt the data in-place, returning the authentication tag.
-    fn encrypt_in_place_detached(
+#[cfg(feature = "inout")]
+pub trait AeadInOut: AeadCore {
+    /// Encrypt the data in the provided [`InOutBuf`], returning the authentication tag.
+    fn encrypt_inout_detached(
         &self,
         nonce: &Nonce<Self>,
         associated_data: &[u8],
-        buffer: &mut [u8],
+        buffer: InOutBuf<'_, '_, u8>,
     ) -> Result<Tag<Self>>;
 
-    /// Decrypt the message in-place, returning an error in the event the provided
-    /// authentication tag does not match the given ciphertext (i.e. ciphertext
+    /// Decrypt the data in the provided [`InOutBuf`], returning an error in the event the
+    /// provided authentication tag is invalid for the given ciphertext (i.e. ciphertext
     /// is modified/unauthentic)
-    fn decrypt_in_place_detached(
+    fn decrypt_inout_detached(
         &self,
         nonce: &Nonce<Self>,
         associated_data: &[u8],
-        buffer: &mut [u8],
+        buffer: InOutBuf<'_, '_, u8>,
         tag: &Tag<Self>,
     ) -> Result<()>;
 }
@@ -267,14 +273,41 @@ pub trait AeadInPlaceDetached: AeadCore {
 /// This is the common convention for AEAD algorithms.
 pub trait PostfixTagged {}
 
-impl<T: AeadInPlaceDetached + PostfixTagged> AeadInPlace for T {
+#[cfg(feature = "alloc")]
+impl<Alg: AeadInPlace> Aead for Alg {
+    fn encrypt<'msg, 'aad>(
+        &self,
+        nonce: &Nonce<Self>,
+        plaintext: impl Into<Payload<'msg, 'aad>>,
+    ) -> Result<Vec<u8>> {
+        let payload = plaintext.into();
+        let mut buffer = Vec::with_capacity(payload.msg.len() + Self::TagSize::to_usize());
+        buffer.extend_from_slice(payload.msg);
+        self.encrypt_in_place(nonce, payload.aad, &mut buffer)?;
+        Ok(buffer)
+    }
+
+    fn decrypt<'msg, 'aad>(
+        &self,
+        nonce: &Nonce<Self>,
+        ciphertext: impl Into<Payload<'msg, 'aad>>,
+    ) -> Result<Vec<u8>> {
+        let payload = ciphertext.into();
+        let mut buffer = Vec::from(payload.msg);
+        self.decrypt_in_place(nonce, payload.aad, &mut buffer)?;
+        Ok(buffer)
+    }
+}
+
+#[cfg(feature = "inout")]
+impl<T: AeadInOut + PostfixTagged> AeadInPlace for T {
     fn encrypt_in_place(
         &self,
         nonce: &Nonce<Self>,
         associated_data: &[u8],
         buffer: &mut dyn Buffer,
     ) -> Result<()> {
-        let tag = self.encrypt_in_place_detached(nonce, associated_data, buffer.as_mut())?;
+        let tag = self.encrypt_inout_detached(nonce, associated_data, buffer.as_mut().into())?;
         buffer.extend_from_slice(tag.as_slice())?;
         Ok(())
     }
@@ -293,38 +326,12 @@ impl<T: AeadInPlaceDetached + PostfixTagged> AeadInPlace for T {
         let (msg, tag) = buffer.as_mut().split_at_mut(tag_pos);
         let tag = Tag::<Self>::try_from(&*tag).expect("tag length mismatch");
 
-        self.decrypt_in_place_detached(nonce, associated_data, msg, &tag)?;
+        self.decrypt_inout_detached(nonce, associated_data, msg.into(), &tag)?;
         buffer.truncate(tag_pos);
         Ok(())
     }
 }
 
-#[cfg(feature = "alloc")]
-impl<Alg: AeadInPlace> Aead for Alg {
-    fn encrypt<'msg, 'aad>(
-        &self,
-        nonce: &Nonce<Self>,
-        plaintext: impl Into<Payload<'msg, 'aad>>,
-    ) -> Result<Vec<u8>> {
-        let payload = plaintext.into();
-        let mut buffer = Vec::with_capacity(payload.msg.len() + Self::TagSize::to_usize());
-        buffer.extend_from_slice(payload.msg);
-        self.encrypt_in_place(nonce, payload.aad, &mut buffer)?;
-        Ok(buffer)
-    }
-
-    fn decrypt<'msg, 'aad>(
-        &self,
-        nonce: &Nonce<Self>,
-        ciphertext: impl Into<Payload<'msg, 'aad>>,
-    ) -> Result<Vec<u8>> {
-        let payload = ciphertext.into();
-        let mut buffer = Vec::from(payload.msg);
-        self.decrypt_in_place(nonce, payload.aad, &mut buffer)?;
-        Ok(buffer)
-    }
-}
-
 /// AEAD payloads (message + AAD).
 ///
 /// Combination of a message (plaintext or ciphertext) and