From 6a707aef57fd2fb43ef1e6270b2e11578cfd4f23 Mon Sep 17 00:00:00 2001
From: Jesper Louis Andersen <jesper.louis.andersen@gmail.com>
Date: Wed, 26 Nov 2014 14:24:14 +0100
Subject: [PATCH] Write test cases for the streaming API.

---
 eqc_test/enacl_eqc.erl | 36 ++++++++++++++++++++++++++++++++++++
 src/enacl.erl          | 13 ++++++++++++-
 2 files changed, 48 insertions(+), 1 deletion(-)

diff --git a/eqc_test/enacl_eqc.erl b/eqc_test/enacl_eqc.erl
index 722cb74..94d111b 100644
--- a/eqc_test/enacl_eqc.erl
+++ b/eqc_test/enacl_eqc.erl
@@ -177,6 +177,42 @@ prop_secretbox_failure_integrity() ->
         equals(Err, {error, failed_verification})
       end).
 
+prop_stream_correct() ->
+    ?FORALL({Len, Nonce, Key},
+            {int(),
+             fault_rate(1, 40, nonce()),
+             fault_rate(1, 40, secret_key())},
+        case Len >= 0 andalso nonce_valid(Nonce) andalso secret_key_valid(Key) of
+          true ->
+              CipherStream = enacl:stream(Len, Nonce, Key),
+              equals(Len, byte_size(CipherStream));
+          false ->
+              try
+                enacl:stream(Len, Nonce, Key),
+                false
+              catch
+                error:badarg -> true
+              end
+        end).
+
+prop_stream_xor_correct() ->
+    ?FORALL({Msg, Nonce, Key},
+            {binary(),
+             fault_rate(1, 40, nonce()),
+             fault_rate(1, 40, secret_key())},
+        case nonce_valid(Nonce) andalso secret_key_valid(Key) of
+            true ->
+                CipherText = enacl:stream_xor(Msg, Nonce, Key),
+                equals(Msg, enacl:stream_xor(CipherText, Nonce, Key));
+            false ->
+                try
+                  enacl:stream_xor(Msg, Nonce, Key),
+                  false
+                catch
+                  error:badarg -> true
+                end
+        end).
+        
 %% HASHING
 %% ---------------------------
 diff_pair(Sz) ->
diff --git a/src/enacl.erl b/src/enacl.erl
index b99e199..828f640 100644
--- a/src/enacl.erl
+++ b/src/enacl.erl
@@ -31,9 +31,13 @@
 	secretbox/3,
 	secretbox_open/3,
 	secretbox_nonce_size/0,
-	secretbox_key_size/0
+	secretbox_key_size/0,
+	
+	stream/3,
+	stream_xor/3
 ]).
 
+%% Low-level functions
 -export([
 	hash/1,
 	verify_16/2,
@@ -145,6 +149,13 @@ secretbox_nonce_size() ->
 secretbox_key_size() ->
     enacl_nif:crypto_secretbox_KEYBYTES().
 
+stream(Len, Nonce, Key) when is_integer(Len), Len >= 0 ->
+    enacl_nif:crypto_stream(Len, Nonce, Key);
+stream(_, _, _) -> error(badarg).
+
+stream_xor(Msg, Nonce, Key) ->
+    enacl_nif:crypto_stream_xor(Msg, Nonce, Key).
+    
 %% Helpers
 p_zerobytes() ->
 	binary:copy(<<0>>, enacl_nif:crypto_box_ZEROBYTES()).