CAR thieves: beware. Jimmying a lock or punching out an ignition switch to start and steal a car may soon be fruitless activities. If a new, Livermore-developed locking system were installed in the next car you tried to steal, you would find your theft next to impossible. After jimmying the lock, you would be faced with a fiber-optic cable activated only by a specially coded beam of light. Even if you punched out the ignition switch, an identical cable would prevent the engine from starting. Forget hot-wiring; the fiber-optic system would protect not only the door lock but also the ignition system, fuel pump, and starter.
Lawrence Livermore's Bob Clough, Karla Hagans, Richard Main, and Bob Stoddard from Defense and Nuclear Technologies and Engineering directorates developed this novel system (Figure 1, above). The researchers designed the optoelectronic-mechanical lock and key to secure military systems from theft and unauthorized operation, but soon the Light Lock Optical Security System could be used anywhere conventional mechanical locks are used.

A Laser Beam Does the Job
The key is entirely different from those used today. Instead of depending on the mechanical motion of turning in the lock, this key emits laser light from a light-emitting diode or a laser diode. The lock converts the light from the key into electrical power to operate its electronics. The key's light has been "multiplexed" with the code and wavelength required by that particular lock, so the lock must compare the transmitted code from the light to the code it has stored in memory. If they match, the lock opens (Figure 2).
Unlike standard mechanical locks, which have a mechanical connection between the key and the bolt mechanism, Light Lock has no connection, making it almost impossible to manipulate the locking mechanism. In conventional locks, the primary area of weakness is that mechanical connection. A common method of attacking these locks is to bore out the key access and turn the dead bolt. But with no mechanical connection between the key and the bolt, that strategy will not work.
The lock is totally passive with no internal power supply, and the only connection between the key and the lock is light. The combination for the lock can be made to any length desired and can include information other than the code, such as the user or the intended use. The power required by the Light Lock Optical Security System is similar to that found in a typical laser pointer. An added plus is that the key and lock are easily reprogrammed.
Another advantage of this system is that the key and the lock can work together even if they are separated from one another. The laser light from the key can travel along a fiber-optic cable to a vault, for example, that is secured in a buried enclosure. This remote operation feature makes it effective for securely granting access to sites that are a long distance from the person authorizing access.

Computer Data Locked Up Tight
Light Lock can be used not only in place of mechanical locks but also like a password for data access control. A slot in a computer keyboard could accept a Light Lock key or card to activate a lock imbedded in the system. If the key were removed, the terminal would automatically lock up. A key could be "tethered" to an operator so that the operator could not leave a terminal without removing the key. This setup would eliminate unauthorized access to an unattended terminal.
Because Light Lock can transmit information about the authorized key user, an audit trail could be established using the access code and the operator code. Using the computer system's time and date information, each transaction, modification, or access could be stamped and saved. Operator codes in the Light Lock key could also determine levels of access to an application or to a collection of files.

No Competition
No product on the market today competes directly with the Light Lock. It has just one moving part, compared with about 30 on a combination safe and 20 in a conventional tumbler lock. It offers almost 17 million possible combinations, about 40% more than a combination safe and 10 times more than a tumbler lock. Unlike recently designed electromechanical locks, which are not as effective as conventional mechanical locks, Light Lock uses optics in a novel way to create a unique, highly effective security mechanism for protecting valuable assets.
Two things stand in the way of wide acceptance of Light Lock: its size and cost. Within about a year, the team expects to have both problems solved, with a key that is considerably smaller than the current 6-inch length and production costs decreased from about $200 per lock to about $50.
Once those changes are made and Light Lock systems begin to appear on safes, vehicles, homes, industrial facilities, and computer databases, thieves may discover that they are completely out of luck. Even if they know about optoelectronics, they won't be able to overcome the combination of light, electronics, and software.
--Katie Walter

Key Words: fiber-optic systems, laser systems, Light Lock Optical Security System, optoelectronic-mechanical locks, security systems.

For further information contact Robert Stoddard (925) 422-4877 (

Back to October 1998