Function mcrypt_create_iv() is deprecated within CodeIgniter framework

Question

<?php 
class Encryption {
    var $skey     = "1234561234561234"; // 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, $iv);
        return trim($decrypttext);
    }

}

It's my encryption.php file. I tried to solve this error and research lots of time but i could not find proper answer. I am newer in PHP.

Error :

A PHP Error was encountered

Severity: 8192

Message: Function mcrypt_create_iv() is deprecated

Filename: libraries/Encryption.php

Line Number: 27

Answer 1

The manual http://php.net/manual/en/function.mcrypt-create-iv.php states:

Warning

This function was DEPRECATED in PHP 7.1.0, and REMOVED in PHP 7.2.0.

Alternatives to this function include:

• random_bytes()

There is an alternate solution if you don't want to use random_bytes(), and it is shown here:

• PHP 7 - mcrypt deprecated, need alternative