Implement crypto boxing/unboxing for public key cryptographic systems.

eqc_test/enacl_eqc.erl

@@ -5,6 +5,10 @@
 %% CRYPTO BOX
 %% ---------------------------
 
+nonce() ->
+    Sz = enacl:box_nonce_size(),
+    binary(Sz).
+
 prop_box_keypair() ->
     ?FORALL(_X, return(dummy),
         ok_box(enacl:box_keypair())).
@@ -12,6 +16,25 @@ prop_box_keypair() ->
 ok_box({ok, _PK, _SK}) -> true;
 ok_box(_) -> false.
 
+prop_box_correct() ->
+    ?FORALL({Msg, Nonce}, {binary(), nonce()},
+        begin
+            {ok, PK1, SK1} = enacl:box_keypair(),
+            {ok, PK2, SK2} = enacl:box_keypair(),
+            CipherText = enacl:box(Msg, Nonce, PK2, SK1),
+            {ok, DecodedMsg} = enacl:box_open(CipherText, Nonce, PK1, SK2),
+            equals(Msg, DecodedMsg)
+        end).
+
+prop_box_failure_integrity() ->
+    ?FORALL({Msg, Nonce}, {binary(), nonce()},
+        begin
+            {ok, PK1, SK1} = enacl:box_keypair(),
+            {ok, PK2, SK2} = enacl:box_keypair(),
+            CipherText = enacl:box(Msg, Nonce, PK2, SK1),
+            Err = enacl:box_open([<<"x">>, CipherText], Nonce, PK1, SK2),
+            equals(Err, {error, failed_verification})
+        end).
 
 %% HASHING
 %% ---------------------------