If you are using Laravel framework then it's more easy to encrypt and decrypt with internal functions.
$string = 'Some text to be encrypted';
$encrypted = \Illuminate\Support\Facades\Crypt::encrypt($string);
$decrypted_string = \Illuminate\Support\Facades\Crypt::decrypt($encrypted);
var_dump($string);
var_dump($encrypted);
var_dump($decrypted_string);
Note: Be sure to set a 16, 24, or 32 character random string in the key option of the config/app.php file. Otherwise, encrypted values will not be secure.