Abstract: An efficient method and a system for controlling access to a location secured by a lock mechanism controlled by a lock control unit, which may provide a high degree of flexibility and a high level of security. The method includes the steps of storing a first access code in the lock control unit, the first access code being indicative of a predetermined access right to the location, and storing a plurality of access codes including a second access code in an electronic key device. Using the electronic key device, access to the location is requested by initiating transmission of the second access code to the lock control unit where the transmitted second access code is compared with the first access code and, if the first access code corresponds to the second access code, operation of the lock mechanism is initiated. The user can edit and rearrange the plurality of access codes to obtain access to a plurality of locations.