DES licensing comes from the ideas of the Free Software Foundation. Since version 3.0, it is distributed under version 3 of the GNU Lesser General Public License (LGPL), which supplements version 3 of the GNU General Public License.

DES is free software: you can redistribute it and/or modify it under the terms of the GNU Lesser 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 Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public License along with this program. If not, see http://www.gnu.org/licenses/.

DES versions prior to 3.0 were distributed under GNU General Public License (GPL) version 2