WinZip: the world’s leading Zip file utility for file compression, encryption, packaging, and data backup. WinZip ses time and space, making it easy to zip and unzip files for quick, efficient and secure data transmission and storage.

7-Zip is open source software. Most of the source code is under the GNU LGPL license. The unRAR code is under a mixed license: GNU LGPL + unRAR restrictions.