PKWare, a company behind numerous compression programs over the years, today released a free version of SecureZIP. SecureZIP is a light encryption suite designed to help people protect emails and other data on a PC. Normally, the business version of this software runs for around $50. Now, however, if you're a desktop user, you can get it free, though maybe not forever.
The page does mention it is a full license, not a trial, though you may not be able to upgrade it in future. Either way, free is free and you may as well try. Sadly, of course, the suite is Windows only.