Introduce a scalarmult variant which is safe from arguments swaps.

src/enacl.erl

@@ -67,7 +67,7 @@
 
 %% Curve 25519.
 -export([
-	curve25519_scalarmult/2
+	curve25519_scalarmult/1, curve25519_scalarmult/2
 ]).
 
 %% Ed 25519.
@@ -689,6 +689,13 @@ onetime_auth_key_size() -> enacl_nif:crypto_onetimeauth_KEYBYTES().
 curve25519_scalarmult(Secret, BasePoint) ->
 	enacl_nif:crypto_curve25519_scalarmult(Secret, BasePoint).
 
+%% @doc curve25519_scalarmult/1 avoids messing up arguments.
+%% Takes as input a map `#{ secret := Secret, base_point := BasePoint }' in order to avoid
+%% messing up the calling order.
+%% @end
+curve25519_scalarmult(#{ secret := Secret, base_point := BasePoint }) ->
+    curve25519_scalarmult(Secret, BasePoint).
+
 %% Ed 25519 Crypto
 %% ---------------
 %% @doc crypto_sign_ed25519_keypair/0 creates a new Ed 25519 Public/Secret keypair.