说明：  一个用于检测PHP代码安全的脚本，通过分析代码中的信息熵来识别其中所包含的危险代码，即便经过一定程度的代码混淆，依然可以检测出来
(One for detecting the PHP script code security, identification the dangerous code contained therein, even after a certain degree of obfuscation, still can be detected by analyzing the information entropy code)