Abstract: Disclosed is a method in which a key is acquired; access information is generated; and the access information is encrypted with the key. Further, an indicator is associated with the access information and first data is output. The first data includes the access information encrypted with the key and the indicator. Third data is acquired from an apparatus having a key for decrypting the encrypted access information, and the third data includes a code word and an indicator. Access information is determined from the third data, and it is ascertained whether the code word authorizes access. Access is granted to a compartment installation if it was ascertained that the code word authorizes access. Two associated methods, one performed by a mobile apparatus, and another performed by a system are disclosed. Furthermore, corresponding apparatuses, systems, and computer programs are disclosed.