Jenssegers\Optimus\Optimus::encode PHP Method

    public function encode($value)
    {
        if (!is_numeric($value)) {
            throw new InvalidArgumentException('Argument should be an integer');
        }
        switch (static::$mode) {
            case self::MODE_GMP:
                return gmp_intval(gmp_mul($value, $this->prime)) & static::MAX_INT ^ $this->xor;
            default:
                return (int) $value * $this->prime & static::MAX_INT ^ $this->xor;
        }
    }

 /**
  * Encode the given integer.
  *
  * @param int $value
  *
  * @return int
  */
 public function encode($value)
 {
     return $this->obfuscator->encode($value);
 }