A security system comprising: an access door of a secured area protected by the security system; a lock adapted to control access into the secured area through the access door; a controller coupled to the lock; a radio frequency identification, RFID card permanently located near the access door containing an encrypted file, wherein the encrypted file includes an identifier of the access door and an identifier of the security system, and is encrypted using one or more public and private keys; a portable wireless device adapted to transmit a wireless entry request message or signal to the RFID card including an identifier of a user of the portable wireless device and the identifier of the security system; and a processor within the RFID card adapted to compare the identifier of the security system and the identifier of the user of the portable wireless device with one or more authorized identifiers; wherein the RFID card is adapted to transmit the encrypted file to the portable wireless device when both the identifier of the security system and the identifier of the user of the portable wireless device match the one or more authorized identifiers; wherein the portable wireless device is adapted to decrypt the encrypted file using the one or more public and private keys to recover the identifier of the security system and the identifier of the access door and to wirelessly transfer the identifier of the access door, the identifier of the security system and the identifier of the user of the portable wireless device to the controller; and wherein the controller is adapted to compare each of the identifier of the user of the portable wireless device, the identifier of the security system and the identifier of the access door with respective lists of identifiers, to determine that each of the identifier of the portable wireless device, the identifier of the security system and the identifier of the access door matches a respective identifier in the respective lists of identifiers, and to activate the lock to allow physical entry into the secured area when each of the identifier of the user of the portable wireless device and the identifier of the access door matches the respective identifier in the respective lists of identifiers. an access door of a secured area protected by the security system; a lock adapted to control access into the secured area through the access door; a controller coupled to the lock; a radio frequency identification, RFID card permanently located near the access door containing an encrypted file, wherein the encrypted file includes an identifier of the access door and an identifier of the security system, and is encrypted using one or more public and private keys; a portable wireless device adapted to transmit a wireless entry request message or signal to the RFID card including an identifier of a user of the portable wireless device and the identifier of the security system; and a processor within the RFID card adapted to compare the identifier of the security system and the identifier of the user of the portable wireless device with one or more authorized identifiers; wherein the RFID card is adapted to transmit the encrypted file to the portable wireless device when both the identifier of the security system and the identifier of the user of the portable wireless device match the one or more authorized identifiers; wherein the portable wireless device is adapted to decrypt the encrypted file using the one or more public and private keys to recover the identifier of the security system and the identifier of the access door and to wirelessly transfer the identifier of the access door, the identifier of the security system and the identifier of the user of the portable wireless device to the controller; and wherein the controller is adapted to compare each of the identifier of the user of the portable wireless device, the identifier of the security system and the identifier of the access door with respective lists of identifiers, to determine that each of the identifier of the portable wireless device, the identifier of the security system and the identifier of the access door matches a respective identifier in the respective lists of identifiers, and to activate the lock to allow physical entry into the secured area when each of the identifier of the user of the portable wireless device and the identifier of the access door matches the respective identifier in the respective lists of identifiers.