openpgp: Move Nettle AEAD implementation to the backend module

1 files changed, 62 insertions, 0 deletions

diff --git a/openpgp/src/crypto/backend/nettle/aead.rs b/openpgp/src/crypto/backend/nettle/aead.rs
new file mode 100644
index 00000000..1614a20a
--- /dev/null
+++ b/openpgp/src/crypto/backend/nettle/aead.rs
@@ -0,0 +1,62 @@
+//! Implementation of AEAD using Nettle cryptographic library.
+use nettle::{aead, cipher};
+
+use crate::{Error, Result};
+
+use crate::crypto::aead::Aead;
+use crate::types::{AEADAlgorithm, SymmetricAlgorithm};
+
+impl<T: nettle::aead::Aead> Aead for T {
+    fn update(&mut self, ad: &[u8]) {
+        self.update(ad)
+    }
+    fn encrypt(&mut self, dst: &mut [u8], src: &[u8]) {
+        self.encrypt(dst, src)
+    }
+    fn decrypt(&mut self, dst: &mut [u8], src: &[u8]) {
+        self.decrypt(dst, src)
+    }
+    fn digest(&mut self, digest: &mut [u8]) {
+        self.digest(digest)
+    }
+    fn digest_size(&self) -> usize {
+        self.digest_size()
+    }
+}
+
+impl AEADAlgorithm {
+    pub(crate) fn context(
+        &self,
+        sym_algo: SymmetricAlgorithm,
+        key: &[u8],
+        nonce: &[u8],
+    ) -> Result<Box<dyn Aead>> {
+        match self {
+            AEADAlgorithm::EAX => match sym_algo {
+                SymmetricAlgorithm::AES128 => Ok(Box::new(
+                    aead::Eax::<cipher::Aes128>::with_key_and_nonce(key, nonce)?,
+                )),
+                SymmetricAlgorithm::AES192 => Ok(Box::new(
+                    aead::Eax::<cipher::Aes192>::with_key_and_nonce(key, nonce)?,
+                )),
+                SymmetricAlgorithm::AES256 => Ok(Box::new(
+                    aead::Eax::<cipher::Aes256>::with_key_and_nonce(key, nonce)?,
+                )),
+                SymmetricAlgorithm::Twofish => Ok(Box::new(
+                    aead::Eax::<cipher::Twofish>::with_key_and_nonce(key, nonce)?,
+                )),
+                SymmetricAlgorithm::Camellia128 => Ok(Box::new(
+                    aead::Eax::<cipher::Camellia128>::with_key_and_nonce(key, nonce)?,
+                )),
+                SymmetricAlgorithm::Camellia192 => Ok(Box::new(
+                    aead::Eax::<cipher::Camellia192>::with_key_and_nonce(key, nonce)?,
+                )),
+                SymmetricAlgorithm::Camellia256 => Ok(Box::new(
+                    aead::Eax::<cipher::Camellia256>::with_key_and_nonce(key, nonce)?,
+                )),
+                _ => Err(Error::UnsupportedSymmetricAlgorithm(sym_algo).into()),
+            },
+            _ => Err(Error::UnsupportedAEADAlgorithm(self.clone()).into()),
+        }
+    }
+}