Building or Enclosure Termination Closing and/or Opening Apparatus, and Method for Operating a Building or Enclosure Termination

The invention relates to a building or enclosure termination opening and/or closing apparatus having communication signed or encrypted by means of a key, and to a method for operating such. To allow simple, convenient and secure use by exclusively authorised users, the apparatus comprises: a first and a second user terminal, with secure forwarding of a time-limited key from the first to the second user terminal being possible. According to an alternative, individual keys are generated by a user identification and a secret device key.