Implement cryptography for secret boxes.

src/enacl.erl

@@ -1,5 +1,6 @@
 -module(enacl).
 
+%% Public key crypto
 -export([
 	box_keypair/0,
 	box/4,
@@ -7,21 +8,29 @@
 	box_nonce_size/0
 ]).
 
+%% Secret key crypto
+-export([
+	secretbox/3,
+	secretbox_open/3,
+	secretbox_nonce_size/0,
+	secretbox_key_size/0
+]).
+
 -export([
 	hash/1
 ]).
 
 hash(Bin) ->
 	enacl_nif:crypto_hash(Bin).
-	
+
 box_keypair() ->
 	enacl_nif:crypto_box_keypair().
 
 box(Msg, Nonce, PK, SK) ->
-    enacl_nif:crypto_box([zerobytes(), Msg], Nonce, PK, SK).
+    enacl_nif:crypto_box([p_zerobytes(), Msg], Nonce, PK, SK).
     
 box_open(CipherText, Nonce, PK, SK) ->
-    case enacl_nif:crypto_box_open([box_zerobytes(), CipherText], Nonce, PK, SK) of
+    case enacl_nif:crypto_box_open([p_box_zerobytes(), CipherText], Nonce, PK, SK) of
         {error, Err} -> {error, Err};
         Bin when is_binary(Bin) -> {ok, Bin}
     end.
@@ -29,9 +38,30 @@ box_open(CipherText, Nonce, PK, SK) ->
 box_nonce_size() ->
 	enacl_nif:crypto_box_NONCEBYTES().
 
+secretbox(Msg, Nonce, Key) ->
+    enacl_nif:crypto_secretbox([s_zerobytes(), Msg], Nonce, Key).
+    
+secretbox_open(CipherText, Nonce, Key) ->
+    case enacl_nif:crypto_secretbox_open([s_box_zerobytes(), CipherText], Nonce, Key) of
+        {error, Err} -> {error, Err};
+        Bin when is_binary(Bin) -> {ok, Bin}
+    end.
+
+secretbox_nonce_size() ->
+    enacl_nif:crypto_secretbox_NONCEBYTES().
+    
+secretbox_key_size() ->
+    enacl_nif:crypto_secretbox_KEYBYTES().
+
 %% Helpers
-zerobytes() ->
+p_zerobytes() ->
 	binary:copy(<<0>>, enacl_nif:crypto_box_ZEROBYTES()).
 	
-box_zerobytes() ->
+p_box_zerobytes() ->
 	binary:copy(<<0>>, enacl_nif:crypto_box_BOXZEROBYTES()).
+
+s_zerobytes() ->
+	binary:copy(<<0>>, enacl_nif:crypto_secretbox_ZEROBYTES()).
+	
+s_box_zerobytes() ->
+	binary:copy(<<0>>, enacl_nif:crypto_secretbox_BOXZEROBYTES()).

src/enacl_nif.erl

@@ -12,6 +12,16 @@
 	crypto_box_BOXZEROBYTES/0
 ]).
 
+%% Secret key crypto
+-export([
+	crypto_secretbox/3,
+	crypto_secretbox_open/3,
+	crypto_secretbox_NONCEBYTES/0,
+	crypto_secretbox_ZEROBYTES/0,
+	crypto_secretbox_BOXZEROBYTES/0,
+	crypto_secretbox_KEYBYTES/0
+]).
+
 %% Miscellaneous helper functions
 -export([
 	crypto_hash/1
@@ -39,6 +49,14 @@ crypto_box_keypair() -> not_loaded().
 crypto_box(_PaddedMsg, _Nonce, _PK, _SK) -> not_loaded().
 crypto_box_open(_CipherText, _Nonce, _PK, _SK) -> not_loaded().
 
+crypto_secretbox_NONCEBYTES() -> not_loaded().
+crypto_secretbox_ZEROBYTES() -> not_loaded().
+crypto_secretbox_KEYBYTES() -> not_loaded().
+crypto_secretbox_BOXZEROBYTES() -> not_loaded().
+
+crypto_secretbox(_CipherText, _Nonce, _Key) -> not_loaded().
+crypto_secretbox_open(_CipherText, _Nonce, _Key) -> not_loaded().
+
 crypto_hash(Input) when is_binary(Input) -> not_loaded().