1 function encryptDecrypt($key, $string, $decrypt){ 
 2 
 3     if($decrypt){ 
 4 
 5         $decrypted = rtrim(mcrypt_decrypt(MCRYPT_RIJNDAEL_256, md5($key), base64_decode
 6        ($string), MCRYPT_MODE_CBC, md5(md5($key))), "12"); 
 7 
 8         return $decrypted; 
 9 
10     }else{ 
11 
12         $encrypted = base64_encode(mcrypt_encrypt(MCRYPT_RIJNDAEL_256, md5($key),
13        $string, MCRYPT_MODE_CBC, md5(md5($key)))); 
14 
15         return $encrypted; 
16 
17     } 
18 
19 }

1 //以下是将字符串“Helloweba欢迎您”分别加密和解密 
2 
3 //加密： 
4 
5 echo encryptDecrypt('password', 'Helloweba欢迎您',0); 
6 
7 //解密： 
8 
9 echo encryptDecrypt('password', 'z0JAx4qMwcF+db5TNbp/xwdUM84snRsXvvpXuaCa4Bk=',1);