PHP Locker, the tool worth its cost is a fine application for encoding your PHP source code.
    This reliable application that provides full proof protection in encoding your PHP source code. After encoding your PHP source code with this tool it becomes cryptic to understand it and hard to reverse-engineer it. The other features supporting the tool are: it does not require any changes to the customer's PHP compilation or execution environment, does not require any changes to your source code, its encoded code works well on Intel Linux, FreeBSD, NetBSD, OpenBSD, Solaris, OSX, Windows and so on, it is compatible with ASCII and Unicode (UTF8 or UTF16), the application is compatible with PHP4 and PHP5 versions. The simple interface of the tool is supported with an apprehensive help support that makes it easy to the novice user too.
    The simple tool with powerful features does not require any additional loadable modules on client server.