car key

A car key or an automobile key is a key used to open and/or start an automobile. Modern key designs are usually symmetrical, and some use grooves on both sides, rather than a cut edge, to actuate the lock. It has multiple uses for the automobile with which it was sold. A car key can open the doors, as well as start the ignition, open the glove compartment and also open the trunk (boot) of the car. Some cars come with an additional key known as a valet key that starts the ignition and opens the driver's side door, but prevents the valet from gaining access to valuables that are located in the trunk or the glove box. Some valet keys, particularly those to high-performance vehicles, go so far as to restrict the engine's power output to prevent joyriding. Recently, features such as coded immobilizers have been implemented in newer vehicles. More sophisticated systems make ignition dependent on electronic devices, rather than the mechanical keyswitch. A number of these systems, such as KeeLoq and Megamos Crypto have been demonstrated to be weak and vulnerable to cryptanalytic attacks.Ignition switches or locks are combined with security locking of the steering column (in many modern vehicles) or the gear lever (such as in Saab Automobile vehicles). In the latter, the switch is between the seats, preventing damage to the driver's knee in the event of a collision.
Keyless entry systems, which use a door-mounted keypad, key fob, a wireless-enabled handheld computing device (e.g., smartphone or tablet), or a remote control in place of a toothed key, have become a standard feature on most new cars. Some of them are handsfree in that a vehicle door is automatically unlocked when the user's handheld device is detected within proximity to the vehicle.
Some high-tech automotive keys are billed as theft deterrents. Mercedes-Benz uses a key that, rather than have a cut metal piece to start the car, uses an encoded infrared beam that communicates with the car's computer. If the codes match, the car can be started. These keys can be expensive to replace if lost and can cost up to US $400.
A switchblade key is basically the same as any other car key, except in appearance. The switchblade key is designed to fold away inside the fob when it is not being used. Switchblade keys have become very popular recently because of their smart compact look. These type of keys are also commonly referred as Flip Keys. Because switchblade keys are only developed for new car models, they are usually equipped with a programmed transponder chip.

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