在XML中生成带有内置过期日期的简单许可证，我这样做对吗?

I am currently developing simple apps (in Actionsript 3 if that's relevant), and I wanted to build in a simple registration system, based on an XML file (which would be generated by a PHP script) which would enable my files to 'expire' after a certain date.I am currently developing simple apps (in Actio