A system comprising a physical key, a communication device and a vehicle lock installed on a vehicle memorizing a first cryptographic key called master key in a secure enclave, the vehicle lock being configured to communicate remotely with the communication device, wherein the physical key is configured to provision the communication device with data allowing said communication device to access a vehicle resource by operating remotely the vehicle lock, the physical key comprising a secure enclave also storing the master key, the secure enclave being an embedded secure element or a trusted execution environment, the physical key being further configured to: - establish a communication link with the communication device; - derive by the secure enclave a second cryptographic key called derived key from the master key; and - transmit to the communication device via the secure communication link the derived key, wherein the communication device is configured to store the derived key received from the physical key and wherein the vehicle lock is further configured to: - establish a communication link with the communication device, - on request from the communication device send to the communication device a challenge message comprising a random number; - receive from the communication device a security challenge answer determined by the communication device using the stored derived key and the random number; - generate locally the derived key using the stored master key, compute locally a version of the security challenge answer and verify that it is identical to the one received from the communication device; and - in case of a positive verification, grant the access to the vehicle resource. - establish a communication link with the communication device; - derive by the secure enclave a second cryptographic key called derived key from the master key; and - transmit to the communication device via the secure communication link the derived key, wherein the communication device is configured to store the derived key received from the physical key and wherein the vehicle lock is further configured to: - establish a communication link with the communication device, - on request from the communication device send to the communication device a challenge message comprising a random number; - receive from the communication device a security challenge answer determined by the communication device using the stored derived key and the random number; - generate locally the derived key using the stored master key, compute locally a version of the security challenge answer and verify that it is identical to the one received from the communication device; and - in case of a positive verification, grant the access to the vehicle resource. wherein the communication device is configured to store the derived key received from the physical key and wherein the vehicle lock is further configured to: - establish a communication link with the communication device, - on request from the communication device send to the communication device a challenge message comprising a random number; - receive from the communication device a security challenge answer determined by the communication device using the stored derived key and the random number; - generate locally the derived key using the stored master key, compute locally a version of the security challenge answer and verify that it is identical to the one received from the communication device; and - in case of a positive verification, grant the access to the vehicle resource. - establish a communication link with the communication device, - on request from the communication device send to the communication device a challenge message comprising a random number; - receive from the communication device a security challenge answer determined by the communication device using the stored derived key and the random number; - generate locally the derived key using the stored master key, compute locally a version of the security challenge answer and verify that it is identical to the one received from the communication device; and - in case of a positive verification, grant the access to the vehicle resource.