diff --git a/COPYING.md b/COPYING.md
index b07ce3f3b..4388ade1d 100644
--- a/COPYING.md
+++ b/COPYING.md
@@ -1,9 +1,19 @@
 *Terrarum* by Minjaesong (Torvald)
 
-Copyright (C) 2013-2017 Torvald. All rights reserved.
-mailto: alswo9628 *at* __gmail__ *dot* __com__
+Copyright (C) 2013-2017 Minjaesong (Torvald) 
 
-You can use any assets (sprites, fonts, tiles and codes) for your own goods (e.g. texture pack for Minecraft), provided that you gave necessary credit to this game and me, and also notified me.
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 ----