A mainstay of electronic door entry systems, the key fob has gone through many iterations since its inception in 1983. Early systems, used mainly for car doors, relied on line of sight and used infrared, but were highly susceptible to copying. Systems developed over time to use challenge-response authentication over radio frequency and now operate primarily over a passive radio frequency identification (RFID) tag, which allows the exchange of data through electromagnetic waves.
Key fobs and cards are used with a variety of access control systems and offer a simple way for small businesses to manage entry into their facilities.
They have become increasingly popular due to their ease of use and customization options, which allow businesses to control who accesses what doors, see records of entries and exits, and adjust access as their workforce changes. Wondering if a key card/fob access system is right for you? Here's what you need to know.
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How do key fobs work?
Modern key fobs work through RFID, an intelligent barcode system that uses electromagnetic fields to identify and track data on "tags" that contain the stored information. The information is passed using radio waves.
The barcode system works similarly to a barcode you would see on the back of a physical product or the magnetic strip on your credit card – it requires a reader to gain the information.
To open a door using a key fob, you simply need to hold or wave your fob in front of the reader. Each key fob contains a microchip with a unique frequency that communicates with the reader and indicates that the door should be opened. Fobs can be programmed to allow levels of access for different uses. For example, a building manager's fob can be programmed to access all doors in a facility, while a receptionist's fob may be programmed to allow access to a few areas.
Why are key fobs used?
Key fobs are being widely adopted because of their ease of use and management. They eliminate the process of wiggling a metal key around in a lock – all you have to do is hold or wave the fob over the reader. Proximity keys are another great option for easy entry.
Key fobs provide the same function as traditional keys but offer additional convenience and security. If a fob is lost or you wish to deny someone (say, a former employee or tenant) entry, you can easily cancel access on that particular fob.
Additionally, key fobs allow you to control who can enter which doors and when so that you can, for example, only allow access to a warehouse for warehouse employees during their designated work times. Fobs also provide the option of keeping records of entries and exits so that you can track attendance, visitors or staff mobility.
What is a proximity key?
A proximity key is a fob that allows for keyless entry. The fob communicates with a reader via RFID and communicates that a door should be unlocked. A proximity key is different than a key fob because a key fob must be waved in front of the reader to allow access, whereas the proximity key can remain in a bag or pocket to unlock the door. Proximity keys are primarily used for automobiles but are slowly being adopted for building access control systems.
Where are they used?
Key fobs can be used for cars with keyless entry, apartment or condominium buildings, parking garages, college campuses, gym facilities, office spaces, buildings with restricted areas and more.
What are the costs of a key fob system?
Depending on the system and the features you require, an access control system that uses key fobs and readers will cost around $1,500 to $2,500 per door with access for up to 150 people.
Can you copy a key fob?
Yes. But it is a process that requires some technical knowledge and an RFID reader, which you can buy online and allows you to read and write 125kHz key fobs, which is the most common type used for apartment and office buildings. If you don't want to do it yourself, there are several key-fob-copying services available that will clone your fob for you.
Key fob copying is not a cause for concern. Doing so is equivalent to taking your metal key to the hardware store to have it copied. The copy is an identical clone of your original fob and would be subject to the same allowances and restrictions.
Can smart door locks be hacked?
Yes. Security teams, including RedTeam and Bishop Fox, have demonstrated how hackers can steal badge data from your fob and copy it to their own cards, badges or fobs. The majority of RFID-enabled tags are not encrypted and do not carry any sort of sophisticated protection, which leaves them vulnerable to hackers.
To avoid your fobs being hacked, consider an RFID-blocking sleeve to cover your fob, or change your system to one that does not broadcast information to a hacker's reader, like a rolling code or challenge-response approach. Ryan Smith, owner of KeyCard Ninja, recommends including a printed photo ID if your business uses key cards, because a photo cannot be duplicated onto a new card. [Learn more about protecting your business from hacking here].
Do magnets affect key fobs?
No, the common magnet is not strong enough to affect your key fob.
Can a locksmith program a key fob?
It will depend on the system that you use and the locksmith. Some larger locksmiths offer the service, but you should contact your access control system provider first to see what support options they provide. [Looking for an access control system? See our Best Picks here].
Do you have to reprogram a key fob after replacing the battery?
Generally, no. If you have a professional replace your battery, they should be able to do it without needing to reprogram the fob(s).