Abstract: A method of controlling access to a location secured by a lock mechanism. An access control management system (ACMS) administrates electronic keys for multiple locations and users carrying mobile units. A lock mechanism controls the lock mechanism at the location. Each of data records associated with lock control units includes key generation data for generating an electronic key for a corresponding lock control unit. A generated key is communicated from the ACMS to the user mobile unit. The key indicates an access right to the location and has an associated lock control unit identifier. The key is communicated from the user mobile unit to the lock control unit at the location, which authenticates the key and, subject to successful authentication of the key, operates the lock mechanism. The key includes a data item cryptographically protected between the ACMS and the lock control unit using a cryptographic key unknown to the user mobile unit.

Abstract: A method of controlling access to a location, the location being secured by a lock mechanism, the system comprising an access control management system adapted to administrate electronic keys for a plurality of locations and a plurality of users, a user mobile unit to be carried by a user, and a lock mechanism operationally coupled to the lock mechanism at said location and adapted to control the lock mechanism, the method comprising: storing, by the access control management system, a plurality of data records associated with respective lock control units, each data record comprising key generation data for generating an electronic key for a corresponding lock control unit; communicating a generated electronic key from the access control management system to the user mobile unit, the electronic key being indicative of a predetermined access right to said location, the electronic key having associated with it a lock control unit identifier of the lock control unit at said location; communicating the electroni