OffByZero Vault is a secure text editor that uses the TripleDES symmetric encryption algorithm. OBZVault is available on MS Windows, Linux, and Mac OS X.
OBZVault was one of the products released by OffByZero Pty. Ltd.; the original product page is here. We have subsequently re-licensed OBZVault under the GNU Lesser General Public License, and created a GitHub project to host it.
The GPL is specifically designed to reduce the usefulness of GPL-licensed code to closed-source, proprietary software. The BSD license (and similar) don't mandate code-sharing if the BSD-licensed code is modified by licensees. The LGPL achieves the best of both worlds: an LGPL-licensed library can be incorporated within closed-source proprietary code, and yet those using an LGPL-licensed library are required to release source code to that library if they change it.