7-ZIP Archiver

7-Zip is open-source software. With its easy-to-use and simple interface, it's one of the most popular file compression programs. Notable for being free, it offers a wide range of compression options. Most of the code is licensed under the GNU LGPL license. The AES code is under the BSD license, while the unRAR code is a mixed license (GNU LGPL + unRAR). You can use 7-Zip on any computer, including those used in advertising campaigns. No fees or registration are required.