As software vendors write more and more commercial applications in PHP it is critical that their intellectual property (all their hard work) is protected.  With more applications providing evaluation copies and electronic downloads it is an even more complicated to insure that they are being distributed securely, whether free, for evaluation or for commercial sale.
Zend Guard (formerly Zend Encoder) protects your applications from reverse engineering and unauthorized customization by providing encoding and obfuscation.  It further protects from unlicensed use and redistribution by providing comprehensive licensing support.  This combined functionality makes software distribution worry free.

• The Encoder
• The License Manager
• How it works
• Zend Optimizer

• The most widely accepted PHP encryption product on the market. Available for over 7 years
• Zend’s dedicated team of developers makes it the most stable and robust encoder on the market
• Streamlined integration with Zend Studio
• The only product that provides with protection for object oriented programs created with PHP 4 or PHP 5

Supported Operating Systems:

• Linux x86
• Windows x86 2000 / XP / 2003 / Vista (32 bit only)
• Mac OS X 10.4, 10.5

Supported PHP Versions:

4.2.x through 5.2.x