source/Core/Encryptor.php
protected function _formKey($key, $string)
    {
        $key = '_' . $key;
        $keyLength = (strlen($string) / strlen($key)) + 5;

        return str_repeat($key, $keyLength);
    }
protected function _formKey($key, $string)
    {
        $key = '_' . $key;
        $keyLength = (strlen($string) / strlen($key)) + 5;

        return str_repeat($key, $keyLength);
    }
protected function _formKey ( $ key , $ string ) { $ key = '_' . $ key ; $ keyLength = ( strlen ( $ string ) / strlen ( $ key ) ) + 5 ; return str_repeat ( $ key , $ keyLength ) ; }
Forms key for use in encoding.

@param string $key
@param string $string

@return string
Forms key for use in encoding .