Access control system

A system for taking an access control decision based on a virtual key received from an NFC device, the system comprising an access control arrangement, comprising an NFC arrangement, comprising an NFC antenna and a memory, and at least one processing device, wherein the memory of the NFC arrangement is a volatile memory, which is physically connected to the at least one processing device,

• wherein the NFC arrangement is arranged to:
• activate an NFC read/write mode in an NFC device with an active NFC field, by the NFC device sensing the NFC antenna in said NFC field;
• allow a virtual key from the NFC device to be written to the memory as an NDEF message, using the NFC read/write mode in the NFC device;
• immediately transfer the NDEF message from the memory to the at least one processing device;
• and
• delete the NDEF message from the memory as soon as it has been transferred to the at least one processing device, and
• wherein the at least one processing device is arranged to:
• receive the NDEF message representing the virtual key from the memory;
• compare the received virtual key to pre-stored valid virtual keys;
• and
• based on said comparison, take an access control decision, to grant or deny access.