Streamline the AEAD API

Author: jlouis

CHANGELOG.md

@@ -9,7 +9,6 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 
 - Go through all calls and make them return streamlined exceptions if applicable.
   Pretty large change, but OTOH, this ought to happen before a 1.0 release as well.
-  - AEAD
   - hash
   - kx
   - randombytes

c_src/aead.c

@@ -57,24 +57,20 @@ enacl_crypto_aead_chacha20poly1305_ietf_encrypt(ErlNifEnv *env, int argc,
   if (!enif_alloc_binary(message.size +
                              crypto_aead_chacha20poly1305_ietf_ABYTES,
                          &ciphertext)) {
-    ret = enacl_error_tuple(env, "alloc_failed");
-    goto done;
+    goto err;
   }
 
-  if (crypto_aead_chacha20poly1305_ietf_encrypt(
-          ciphertext.data, NULL, message.data, message.size, ad.data, ad.size,
-          NULL, nonce.data, key.data) < 0) {
-    ret = enacl_error_tuple(env, "aead_chacha20poly1305_ietf_encrypt_failed");
-    goto release;
-  }
+  crypto_aead_chacha20poly1305_ietf_encrypt(ciphertext.data, NULL, message.data,
+                                            message.size, ad.data, ad.size,
+                                            NULL, nonce.data, key.data);
 
   ret = enif_make_binary(env, &ciphertext);
   goto done;
 
 bad_arg:
   return enif_make_badarg(env);
-release:
-  enif_release_binary(&ciphertext);
+err:
+  ret = enacl_internal_error(env);
 done:
   return ret;
 }
@@ -106,14 +102,13 @@ enacl_crypto_aead_chacha20poly1305_ietf_decrypt(ErlNifEnv *env, int argc,
   if (!enif_alloc_binary(ciphertext.size -
                              crypto_aead_chacha20poly1305_ietf_ABYTES,
                          &message)) {
-    ret = enacl_error_tuple(env, "alloc_failed");
-    goto done;
+    return enacl_internal_error(env);
   }
 
   if (crypto_aead_chacha20poly1305_ietf_decrypt(
           message.data, NULL, NULL, ciphertext.data, ciphertext.size, ad.data,
-          ad.size, nonce.data, key.data) < 0) {
-    ret = enacl_error_tuple(env, "aead_chacha20poly1305_ietf_decrypt_failed");
+          ad.size, nonce.data, key.data) != 0) {
+    ret = enacl_error_tuple(env, "failed_verification");
     goto release;
   }
 
@@ -180,24 +175,20 @@ enacl_crypto_aead_xchacha20poly1305_ietf_encrypt(ErlNifEnv *env, int argc,
   if (!enif_alloc_binary(message.size +
                              crypto_aead_xchacha20poly1305_ietf_ABYTES,
                          &ciphertext)) {
-    ret = enacl_error_tuple(env, "alloc_failed");
-    goto done;
+    goto err;
   }
 
-  if (crypto_aead_xchacha20poly1305_ietf_encrypt(
-          ciphertext.data, NULL, message.data, message.size, ad.data, ad.size,
-          NULL, nonce.data, key.data) < 0) {
-    ret = enacl_error_tuple(env, "aead_xchacha20poly1305_ietf_encrypt_failed");
-    goto release;
-  }
+  crypto_aead_xchacha20poly1305_ietf_encrypt(
+      ciphertext.data, NULL, message.data, message.size, ad.data, ad.size, NULL,
+      nonce.data, key.data);
 
   ret = enif_make_binary(env, &ciphertext);
   goto done;
 
 bad_arg:
   return enif_make_badarg(env);
-release:
-  enif_release_binary(&ciphertext);
+err:
+  ret = enacl_internal_error(env);
 done:
   return ret;
 }
@@ -229,14 +220,13 @@ enacl_crypto_aead_xchacha20poly1305_ietf_decrypt(ErlNifEnv *env, int argc,
   if (!enif_alloc_binary(ciphertext.size -
                              crypto_aead_xchacha20poly1305_ietf_ABYTES,
                          &message)) {
-    ret = enacl_error_tuple(env, "alloc_failed");
-    goto done;
+    return enacl_internal_error(env);
   }
 
   if (crypto_aead_xchacha20poly1305_ietf_decrypt(
           message.data, NULL, NULL, ciphertext.data, ciphertext.size, ad.data,
-          ad.size, nonce.data, key.data) < 0) {
-    ret = enacl_error_tuple(env, "aead_xchacha20poly1305_ietf_decrypt_failed");
+          ad.size, nonce.data, key.data) != 0) {
+    ret = enacl_error_tuple(env, "failed_verification");
     goto release;
   }
 

eqc_test/enacl_eqc.erl

@@ -546,6 +546,29 @@ prop_aead_chacha20poly1305_ietf_fail() ->
     end
   end).
 
+%% * aead_xchacha20poly1305_encrypt/4,
+%% * aead_xchacha20poly1305_decrypt/4,
+prop_aead_xchacha20poly1305_ietf() ->
+  NPubBytes = enacl:aead_xchacha20poly1305_ietf_NPUBBYTES(),
+  ?FORALL({Key, Msg, AD, Nonce},
+          {binary(32), binary(), ?LET(ADBytes, choose(0,16), binary(ADBytes)), binary(NPubBytes)},
+  begin
+    EncryptMsg = enacl:aead_xchacha20poly1305_ietf_encrypt(Msg, AD, Nonce, Key),
+    equals(enacl:aead_xchacha20poly1305_ietf_decrypt(EncryptMsg, AD, Nonce, Key), Msg)
+  end).
+
+prop_aead_xchacha20poly1305_ietf_fail() ->
+  NPubBytes = enacl:aead_xchacha20poly1305_ietf_NPUBBYTES(),
+  ?FORALL({Key, Msg, AD, Nonce},
+          {binary(32), binary(), ?LET(ADBytes, choose(0,16), binary(ADBytes)), binary(NPubBytes)},
+  begin
+    EncryptMsg = enacl:aead_xchacha20poly1305_ietf_encrypt(Msg, AD, Nonce, Key),
+    case enacl:aead_xchacha20poly1305_ietf_decrypt(<<0:8, EncryptMsg/binary>>, AD, Nonce, Key) of
+        {error, _} -> true;
+        _          -> false
+    end
+  end).
+
 %% CRYPTO STREAM
 %% ------------------------------------------------------------
 %% * stream/3

src/enacl.erl

@@ -1152,7 +1152,7 @@ kx_secret_key_size() ->
 %% `AD' using `Key' and `Nonce'. Returns the encrypted message followed by
 %% `aead_chacha20poly1305_ABYTES/0' bytes of MAC.
 %% @end
--spec aead_chacha20poly1305_ietf_encrypt(Msg, AD, Nonce, Key) -> binary() | {error, term()}
+-spec aead_chacha20poly1305_ietf_encrypt(Msg, AD, Nonce, Key) -> binary()
     when Key :: binary(),
          Nonce :: binary(),
          AD :: binary(),
@@ -1207,7 +1207,7 @@ aead_chacha20poly1305_ietf_MESSAGEBYTES_MAX() ->
 %% `AD' using `Key' and `Nonce'. Returns the encrypted message followed by
 %% `aead_xchacha20poly1305_ABYTES/0' bytes of MAC.
 %% @end
--spec aead_xchacha20poly1305_ietf_encrypt(Msg, AD, Nonce, Key) -> binary() | {error, term()}
+-spec aead_xchacha20poly1305_ietf_encrypt(Msg, AD, Nonce, Key) -> binary()
     when Key :: binary(),
          Nonce :: binary(),
          AD :: binary(),