Wireless lock is a protection concept for authenticated LAN or WLAN network clients offered from various vendors in various functional shapes and physical designs.
Beyond that a wireless lock supports automatic log-off after user leaves unlocked network client and independent from time-out conditions.
The protected object returns to status "unlocked" as soon as the distance gets lesser and the received signal strength level higher than set limit.
User guides for mode of operation recommend to bear a very light designed alarm token with a necklace, a wristband or similarly directly bound to the body.
Chosen frequency band and allowed maximum transmission power level define the possible reach for the response from the token in the vicinity of the protected object.
Basically there are different concepts available for implementing a sound security concept: The metrics options for detecting separation of protected object and authenticated user have to take into account various physical phenomena and thus offer a variety of signal processing to overcome The safe approach is travel time estimation with ultra-short pulses (e.g. UWB and CSS), the cheap approach is RSSI estimate with just variation of power levels.
The hosting on PC like systems allows for detecting presence of mobile phones in proximity to PC-attached Bluetooth dongle or equivalent interface.
[6] Transmission power of the wireless token for the object may be very low in the 1 mW range, as just the distance between the bearer and the item to be protected shall be bridged.
Continuous connection based encrypted key exchange between active token and receiver dongle provides a sufficient security level prepared for certification under ISO/IEC 15408 common criteria specification.
Initially connection based encrypted key exchange serves for a lower security level which appears sufficient for most requirements.
All known approaches for wireless locking are either proprietary[7] or just industrial standard, as e.g. ZigBee, ANT or other communication platforms, hence requiring special pairing of token and receiver/transmitter resp.