February 22, 2002
Why Keys Cost a King's Ransom
By MATTHEW L. WALD
BETHESDA, Md. -- Not long ago, if you lost a car key, you could get a duplicate for a buck or two at a hardware store, where a mechanical copy of another surviving key could easily be made. But if you have gotten a replacement lately, chances are you've had a case of lock shock. A key can cost as much as the monthly car payment.
If you lose the key for a new Lexus RX 300, one northern Virginia dealer charges $300 for a replacement. Even for a plain-jane Taurus, the price is $130 at a Ford dealer here. Neither price is unusual. Dealers have the market mostly to themselves; very few locksmiths or hardware stores can copy the keys to late-model cars.
The technology is beyond their capabilities. For most new cars, from the top of the price scale to the bottom, the key is no longer a sliver of notched metal that simply works a mechanical lock; it is now part of an electronic access system, with computer- encoded passwords worthy of James Bond.
Colloquially, the new keys are said to have a computer chip inside. Actually, the head of the key contains a tiny robot radio that communicates with the car. Their electronic handshake may include 19 digits, which allows 10 billion-billion combinations.
While this makes life more complicated for car owners, it poses a bigger hurdle for car thieves, who so far have not caught up. The new keys have helped to slash the theft rate on some models by 90 percent.
Although the keys may be expensive for loss-prone car owners, automakers like the electronic system because it is a cheap way to add theft protection. Indeed, one of the first cars to use the system was the lowbrow Ford Escort, in 1993 in Britain. The system came into general use in the United States in some 1997-model luxury cars.
The key is the equivalent of the old-fashioned "kill switch" that owners used to tuck in a location known only to them, and that cut off the fuel pump or the electrical system. But the key constitutes a passive antitheft system, meaning that it engages without the driver having to touch a switch.
The technology differs among manufacturers, but all are similar. At the heart of the system is a tiny electronic device embedded in the head of the key. This device, called a transponder, is essentially a radio that responds to a query from another radio.
"There's an antenna built into the steering column," said Anthony J. Sabetti, global business manager for radio-frequency identification systems at Texas Instruments, which supplies locking systems to Ford, Toyota and Lexus. "When you stick the key in the ignition, the antenna puts a radio signal out, and it's picked up by a coil in the transponder." The key needs no battery because its coil converts that signal into a little jolt of direct current, which the transponder uses to send a message back to the car.
In older systems, the car sends a question and the key gives a fixed answer. In newer models, Mr. Sabetti said, the car has a random number generator, sending a different message each time the key is inserted.
"When the random number is sent to the key head, the key modifies it in a way that would only be known to the vehicle," he said. The answer from the key "has virtually no relationship to the message sent to the key in the first place," he said, or at least none that an electronic eavesdropper could discern. To anyone who intercepted the electronic message, "it would look like garbage," he said.
Moving to the transponder system has had several effects. One is to cut out locksmiths. "It can run up to $50,000 for the equipment to duplicate the keys for cars," said Randy L. Simpson, president of the Associated Locksmiths of America, a trade association based in Dallas. And that is for each manufacturer; equipping a shop to make keys for all car brands would be well beyond the means of most locksmiths.
Mr. Simpson said a glance at older cars would explain why a new key system was needed. "Mechanical devices were defeated in all kinds of different ways," he said.
One way to defeat a mechanical key is simply to pry the whole lock mechanism out of the steering column and connect the internal wires. But that will not allow a car with a transponder to start because hooking up the wires does not send the proper code to the engine-control module, the computer that runs the fuel-injection system.
Another effect is that the car owner is now at the mercy of the dealer's service department. The amount the dealer charges to make a key partly depends on labor rates, and partly on how the lock system is made.
For example, on a 2001 Ford Taurus, the car can "teach" a key the proper code. But it is built to do so only if the technician starts the car with one of the keys that came with the vehicle, turns it off, starts the car with the second key that came with the vehicle, turns it off, and then inserts the new key — with the metal shaft mechanically cut and the transponder unprogrammed and awaiting instructions.
Lose one of the factory keys and the procedure is much more involved; it means making two new keys and teaching both of them the code, Mr. Simpson said. The Ford dealership here charges an hour's labor for that, at $85 an hour, plus $45 for the key.
The Lexus key is a bit more complicated. Its oversize head includes not only the transponder but also keyless-entry buttons.
Glenn E. Holmes, the technical coordination manager for Lexus, said that for the RX 300 there was an additional layer of protection. Before a dealer can copy a key, the technician must call Lexus headquarters and get authorization. The precaution is a guard against dishonest technicians. "If some issue comes up, we know what time these codes were asked for," he said.
General Motors' keys have a mere 137 billion possible combinations, and a dealer can make a copy with only one of the factory- original keys to work with. But they have another refinement; the systems recognize the difference between a full-access key and a "valet" key that will start the car but cannot be used to "teach" a new key the car's combination, said David T. Proefke, engineering group manager for vehicle security.
In programming its key systems, G.M. set an arbitrary limit of 10 keys per vehicle, but Mr. Proefke said the company could rewrite the software for some special-use vehicles, like taxicabs or other fleet cars, that might require more.
For G.M., the transponder keys are the second generation. The first, in 1986, was a simpler system of embedding resisters into the keys of Corvettes, and later, Camaros and Firebirds. The car runs a current through the keys and recognizes whether the resister is present.
Both systems have been highly effective, Mr. Proefke said, adding that G.M.'s new keys had cut thefts by 60 percent.
But however good the system is, Mr. Simpson of the locksmiths association said this was not the last step in car security. "They haven't defeated it yet," he said. "But I'm sure it's just a matter of time."