ZendGuard 5.5 for Mac was available to download from the developer's website when we last checked. We cannot confirm if there is a free download of this app available. The program lies within Security Tools, more precisely Personal Security. This software for Mac OS X is a product of Zend Technologies Ltd. The most popular version of ZendGuard for Mac is 5.5.
From the developer:
Zend Guard is the industry leading solution for PHP IP protection. Zend Guard provides independent software vendors and IT managers with the ability to safely distribute and manage the distribution of their PHP applications while protecting their source code. Zend Optimizer is a free application that runs the files encoded using Zend Guard and enhances the overall performance of your PHP applications.
You may want to check out more software for Mac, such as Kidwidget, LOCKME or CryptStore, which might be related to ZendGuard.