# File app/models/person.rb, line 22
  def self.ck_login(given_login, given_passwd)
    person = Person.find_by_login(given_login)
    return false if person.blank? or
      person.passwd != Digest::MD5.hexdigest(person.pw_salt + given_passwd)

    person.last_login_at = Time.now
    person.save

    person
  end