Hi Security Vehicle Keys :
Transponder Keys
What is a transponder key? In 1995, car manufacturers began to introduce the transponder technology into 
vehicles. This technology allows a key to 'speak' to the computer in the vehicle. In simple terms, the key is inserted into the ignition switch and the vehicle says 'hey, are you the right key?'. The key then responds with, 'Yes, I am number xxxxx.' The vehicle then checks its list of keys and says, 'okay, then you can start the car,' or 'sorry, but you aren't in my database, you don't belong to this vehicle, so I am not turning over for you.'
In most vehicles made in the last few years, transponders have become the 'norm.' It is becoming less likely that you will purchase a vehicle that doesn't have this technology. What does this mean to you, the end user? There are several implications, and they depend on the car manufacturer. For example, if you purchase a Ford vehicle and are given only one key then you either end up going to the dealer for a second key or to a locksmith who has the computer instrument to program it. If you have two keys, then a knowledgeable 
locksmith can produce a third for you.
If you only have one key and you happen to lose it, then you have to either have your vehicle towed into a dealership to have a key programmed and cut for your vehicle, or you have to have a locksmith who has the technology come out to make you one. The cost of the blank alone starts at $40 and depending on where it is made, you can run into additional programming costs. Make sure to get a complete quote and breakdown when calling around for pricing.
In certain vehicles, if you lose your key then then the computer in the vehicle has to be replaced. This can run you anywhere for $2,000 on up.
There are other vehicles that use a rotating code system, so everytime they are put into the vehicle the key 
number changes. The computer records this change to allow for the use of the key the next time. Where you go to get additional keys made will depend upon the vehicle and the knowledge of the locksmith. Remember, as a general rule, locksmiths are usually less expensive than going to the dealer. Investigate your options to find out.
The current transponder key is the perfect blending of electronics and technology. The mechanical key was limited to the number of keys due to cuts and profiles. Transponder technology has increased that number by billions of possibilities.
V.A.T.S.
There are other technologies, such as V.A.T.S. (vehicle anti-theft system) keys as well. These keys use a resistor to talk to the computer within the vehicle. There are several different numbers for VATS keys, and with the correct instruments, a locksmith can detect this number and create a key or cut a secondary key. These keys generally cost from $25.00 and up.
It's all in the FOB
One of the latest technologies to come out are vehicles that no longer use 'keys' the way we think of them. Instead, they use something that looks like a car remote opening unit. These slide into a place in the car that allows the vehicle to read the information directly from the fob. Some of these key fobs don't even have to be inserted, they just have to be in the vicinity of the vehicle (such as in your pocket or purse). Of course, these key fobs aren't to be confused with alarm or lock remote fobs. (These turn on or off your alarm and/or locks and unlocks your doors.)
What happens if you lose your key fob? Currently, this is a dealer-only item, so if you lose your key fob or it becomes damaged, then you are on your way to the dealership. Fob's can run $300-400 to replace. Some vehicles have an emergency start system that uses an 'old fashioned key' to start the vehicle; however, most people don't carry these with them. With every additional security feature comes the inflated cost of mainentance.
With this added type of security and technology also comes the aspect of making it more difficult for criminals to get a hold of the keys and/or technology to steal these vehicles. The negative is that if these types of vehicles are targetted to be stolen, it will happen with the owner in the vehicle.
This type of technology is currently available in mostly hi-end vehicles, such as Mercedes, BMW, and Audi. Toyota Prius has this option available as well.