Keys and cards
Over the past decade or so, car keys have undergone a significant upgrade. In some cars, they have been completely eliminated.
Metamorphoses of car keys are associated with the need to provide an ever higher level of security from lovers of other people's property. Increasingly, mechanical structures are being replaced by electric and remote-controlled locks. Gone are the days of the complete set 
The keys to the car consisted of three copies: one to open the door, another to open the gas tank and the third to control the ignition switch. If a modern car is equipped with a metal key, then one copy is used to open the locks on the doors and start the vehicle.
Due to manufacturing costs and patent requirements, car manufacturers use a variety of locks and associated keys. The simplest were locks with twist inserts, opened with flat keys with slots on one side. This decision limits the number of possible combinations of abbreviations, sometimes the keyword used was less than the number of series of cars of a given type, so they became repetitive. More effective 
reliable keys with slots made on both sides of the metal core. However, slotted locks had a major drawback. Poorly maintained, in winter conditions they froze inside, which actually prevented the opening of the car. Until recently, she used a completely different lock design. 
Ford company. The key for this type of lock had a characteristic design. A round pin with a diameter of 4 mm was flattened in the end part, and notches of various shapes and sizes were formed on this part, forming a lock code. Although they were less prone to freezing, due to the large internal diameter of the mandrel, thieves could easily destroy them with the so-called snippet.
Currently, car manufacturers are developing new lock designs to better protect the car. Such locks are equipped with keys made in the form of a rectangular strip of metal, on both sides of which tracks with an individual hard-to-copy pattern are milled. In most modern cars, metal 
the key is an addition to the large control part, the alarm and immobilizer modules of which, as well as the buttons for opening the central lock, dominate the metal part with notches. Inside the plastic case is a battery, which is a reservoir of energy for electrical circuits. When the battery runs out, the device stops working and it becomes impossible to open the door or start the engine. Therefore, it is recommended to replace the key battery once a year before the upcoming winter. When replacing the battery, the time during which the electronics remain de-energized should be as short as possible. For safety reasons, this procedure should be entrusted to authorized mechanics.
In the past few years, when electronics have become very popular in cars, key cards have been introduced that allow you to open a car door, and after inserting it into a special reader, start the engine with the start-stop button. The electronic card protects the car very well, but stops working if there is no power in the internal or car battery. The "electronic" key must be protected from falling onto hard surfaces and from moisture. To enable the car to be opened when the electronics fail, some cards contain a metal key.
Central locking, activated with the alarm, has become almost standard, the traditional key is a thing of the past.
