Revert "Update enacl dep and fix some minor details (#1)"

This reverts commit 479ec70870.

src/enoise_cipher_state.erl

@@ -54,8 +54,12 @@ set_nonce(CState = #noise_cs{}, Nonce) ->
 encrypt_with_ad(CState = #noise_cs{ k = empty }, _AD, PlainText) ->
     {ok, CState, PlainText};
 encrypt_with_ad(CState = #noise_cs{ k = K, n = N, cipher = Cipher }, AD, PlainText) ->
-    Encrypted = enoise_crypto:encrypt(Cipher, K, N, AD, PlainText),
-    {ok, CState#noise_cs{ n = N+1 }, Encrypted}.
+    case enoise_crypto:encrypt(Cipher, K, N, AD, PlainText) of
+        Encrypted when is_binary(Encrypted) ->
+            {ok, CState#noise_cs{ n = N+1 }, Encrypted};
+        Err = {error, _} ->
+            Err
+    end.
 
 -spec decrypt_with_ad(CState :: state(), AD :: binary(), CipherText :: binary()) ->
                 {ok, state(), binary()} | {error, term()}.

src/enoise_crypto.erl

@@ -65,7 +65,8 @@ rekey(Cipher, K) ->
 
 -spec encrypt(Cipher :: enoise_cipher_state:noise_cipher(),
               Key :: binary(), Nonce :: non_neg_integer(),
-              Ad :: binary(), PlainText :: binary()) -> binary().
+              Ad :: binary(), PlainText :: binary()) ->
+                binary() | {error, term()}.
 encrypt('ChaChaPoly', K, N, Ad, PlainText) ->
     Nonce = <<0:32, N:64/little-unsigned-integer>>,
     enacl:aead_chacha20poly1305_ietf_encrypt(PlainText, Ad, Nonce, K);