PHP Fatal error: Call to a member function encode() on a non-object

Hello

Today I was try to install and using insert-php plugin in the first time.

However, I found a problem when I try to put a custom class that I provide into functions.php name ‘Encryption’ and a code was following:

class Encryption {
    var $skey     = 'Key2015'; // you can change it

    public function safe_b64encode($string) {

        $data = base64_encode($string);
        $data = str_replace(array('+','/','='),array('-','_',''),$data);
        return $data;
    }

    public function safe_b64decode($string) {
        $data = str_replace(array('-','_'),array('+','/'),$string);
        $mod4 = strlen($data) % 4;
        if ($mod4) {
            $data .= substr('====', $mod4);
        }
        return base64_decode($data);
    }

    public function encode($value){

        if(!$value){return false;}
        $text = $value;
        $iv_size = mcrypt_get_iv_size(MCRYPT_RIJNDAEL_256, MCRYPT_MODE_ECB);
        $iv = mcrypt_create_iv($iv_size, MCRYPT_RAND);
        $crypttext = mcrypt_encrypt(MCRYPT_RIJNDAEL_256, $this->skey, $text, MCRYPT_MODE_ECB, $iv);
        return trim($this->safe_b64encode($crypttext));
    }

    public function decode($value){

        if(!$value){return false;}
        $crypttext = $this->safe_b64decode($value);
        $iv_size = mcrypt_get_iv_size(MCRYPT_RIJNDAEL_256, MCRYPT_MODE_ECB);
        $iv = mcrypt_create_iv($iv_size, MCRYPT_RAND);
        $decrypttext = mcrypt_decrypt(MCRYPT_RIJNDAEL_256, $this->skey, $crypttext, MCRYPT_MODE_ECB, $iv);
        return strtolower(trim($decrypttext));
    }
}

$enc = new Encryption();

After that I want to use $enc function to call encode() in a post. So, I put a php code between [insert_php]…[/insert_php] like [insert_php]echo $enc->encode(number);[/insert_php]

However after I publish and view post. It was error as blank page with no information and I notice it was generate error_log following:

[12-Mar-2015 16:54:14 UTC] PHP Fatal error: Call to a member function encode() on a non-object in /home/…/wp-content/plugins/insert-php/insert_php.php(47) : eval()’d code on line 1

Can I solved this problem?

P.S. class Encryption() working if put directly into any php page such header.php but not working when try to using in a post with [insert_php]…[/insert_php]

Thank you

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