php - codeigniter url encrypt not working -

<a href="<?php echo base_url().'daily_report/index/'.$this->encrypt->encode($this->session->userdata('employee_id')) ?>"> 

i have encrypted above url using codeigniter encrypt set encryption key in codeigniter config file

$config['encryption_key'] = 'giouetfdwgzbl2bje9bx5b0rlsd0gkdv'; 

and called in autoload

$autoload['libraries'] = array('session','form_validation','encrypt','encryption','database'); 

when ulr(href) load url this

http://localhost/hrms/daily_report/index/fvjgcz4qqztqak0jaomjiafbz/vkvsbug1igpqekqcz/k7+wue4e/m9u1ejwh3uktkeihexjgkk1dj2awl0+zq== 

but url not decoded, , i;m not getting employee_id shows empty.

public function index($employee_id) {         $save_employee_id = $employee_id;         // decoding encrypted employee id         $get_employee_id = $this->encrypt->decode($save_employee_id);         echo $employee_id; // answer: fvjgcz4qqztqak0jaomjiafbz         echo "<br>";         echo $get_employee_id; // display null         echo "<br>";          exit();         // employee daily report         $data['get_ind_report'] =           $this->daily_report_model->get_ind_report($get_employee_id);         // daily report page         $data['header'] = "daily report";         $data['sub_header'] = "all";         $data['main_content'] = "daily_report/list";         $this->load->view('employeelayout/main',$data);     } 

complete url(3) is

fvjgcz4qqztqak0jaomjiafbz/vkvsbug1igpqekqcz/k7+wue4e/m9u1ejwh3uktkeihexjgkk1dj2awl0+zq== 

it shows only

fvjgcz4qqztqak0jaomjiafbz 

i tried change in the

$config['permitted_uri_chars'] = 'a-za-z 0-9~%.:_\-@=+'; 

by / in permitted uri chars throwing error so, need encryption $id in url using codeigniter encrypt class , decrypt in server side actual $id, fetch data db. appreciated

you have extend encryption class , avoid / working. place class in application/libraries folder. , name my_encrypt.php.

class my_encrypt extends ci_encrypt {     /**      * encodes string.      *       * @param string $string string encrypt.      * @param string $key[optional] key encrypt with.      * @param bool $url_safe[optional] specifies whether or not      *                returned string should url-safe.      * @return string      */     function encode($string, $key="", $url_safe=true)     {         $ret = parent::encode($string, $key);          if ($url_safe)         {             $ret = strtr(                     $ret,                     array(                         '+' => '.',                         '=' => '-',                         '/' => '~'                     )                 );         }          return $ret;     }      /**      * decodes given string.      *       * @access public      * @param string $string encrypted string decrypt.      * @param string $key[optional] key use decryption.      * @return string      */     function decode($string, $key="")     {         $string = strtr(                 $string,                 array(                     '.' => '+',                     '-' => '=',                     '~' => '/'                 )         );          return parent::decode($string, $key);     } }