object Application extends Controller {

  val salt = "my secret key"

  //SHA-1, SHA-256 + salt

  def mk_hash(s: String) : String = {

    val hash_fun = MessageDigest.getInstance("SHA-1")

    hash_fun.digest((s + salt).getBytes).map{ "%02x".format(_) }.mkString

  }

  def gt_cookie(c: Option[Cookie]) : Int = 

    c.map(_.value.split("/")) match {

      case Some(Array(s, h)) 

        if (s.forall(_.isDigit) && mk_hash(s) == h) => s.toInt 

      case _ => 0

    }

  def mk_cookie(i: Int) : Cookie = {

    val s = i.toString

    Cookie("visits", s + "/" + mk_hash(s))

  }

  def index = Action { request => ... }

}