base64_encode是加密,而base64_decode是解密

base64_encode    语法:string base64_encode(string data);

$string='www.lanniaofei.com';   //定义字符串

echo base64_encode($string);   // 输出编码后的内容为 d3d3LmxhenliaXJkZmx5LmNvbQ==
 

base64_decode    语法:string base64_decode(string data);

$string='d3d3LmxhenliaXJkZmx5LmNvbQ==';     //定义字符串

echo base64_decode($string);        //输出解码后的内容 www.lanniaofei.com