Mechatronic Systems: Basics on technology

Instead of classic keys, mechatronic locking systems use various electric "tokens" that usually communicate with the electronic lock via a radio interface to trigger a locking process, at doors as well as at turnstiles and barriers or even furniture locks. They can also be used to arm alarm systems. Accesses and access attempts can be logged in various systems and stored for later analysis, for example to identify the token used after a theft. A wide variety of technologies are used in the tokens: Battery-powered handheld transmitters often radio in the 433 MHz or 868 MHz frequency bands at the push of a button, with a range of about 100 meters.

Passive RFID transponders operate without batteries and are available in various forms (cards, discs, wristbands, [glass] transponders, etc.). They respond automatically to requests from a nearby reader, with the range for contactless smart cards on 13.56 MHz varying from about 10 cm according to ISO 14443 (e.g., NXP Mifare, Sony Felica, electronic ID card) to about 1 m according to ISO 15693 (e.g., HID iClass).

Typical 125 kHz transponders (e.g. NXP Hitag or Texas Instruments DST in immobilizers) can be read from approx. 50 cm to 1 m.

In some cases, mixed forms of RFID and active transmitters are also encountered, e.g., in the "smart keys" of modern luxury vehicles, which respond to a 125 kHz request from an RFID reader by actively transmitting on 433 MHz or 868 MHz. Smartphones equipped with NFC (Near Field Communication), which are compatible with contactless smartcards and also have other features, are also currently being used in access control.
interfaces (UMTS, GPS, Bluetooth).

Regardless of the different modes of operation, communication, and power supply, all of the technologies listed are nowadays suitable for executing modern cryptographic procedures.