diff --git a/LICENSE.txt b/LICENSE.txt
index f5a12a9..c8f4269 100644
--- a/LICENSE.txt
+++ b/LICENSE.txt
@@ -3,7 +3,9 @@ The MIT License (MIT)
 Copyright (c) 2016 John Tromp
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
-of this software and associated documentation files (the "Software"), to deal
+of this software, EXCEPT FOR blake2b.cu WHICH ORIGINATES FROM
+https://github.com/tpruvot/ccminer/blob/windows/sia/sia.cu,
+and associated documentation files (the "Software"), to deal
 in the Software without restriction, including without limitation the rights
 to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 copies of the Software, and to permit persons to whom the Software is