Reviewed by Web Webster
Key Takeaways
- A key fob is a physical device that uses radio frequency identification (RFID) and symmetric encryption to control access to physical spaces.
- Using a fob enables contactless unlocking for users, since the device uses RFID to communicate with and control access to the controlled space.
- Key fobs can take a number of forms, including small devices, key cards and more recently, programmable mobile apps.
What Is a Key Fob?
A key fob is a small hardware device that can be programmed to control access to a physical space. Cars, privately owned buildings and restricted spaces are frequently secured in this way.
Fobs are just one subset of the growing category of security tokens. Other examples include programmable key cards (common in hotels) and increasingly, mobile based security applications.
If your car, hotel room or office uses a fob, you don’t need to unlock it manually. Instead, the mechanism in the fob enables it to open the paired device remotely, within the given range.
Key fobs use two central technologies to limit access to authenticated users in a given system:
- Radio frequency idenntification (RFID)
- Symmetric encryption
A key fob contains a short range radio transmitter and receiver, and uses radio frequency identification (RFID) to communicate with its paired device.
The fob uses radio communication to send encrypted data to the vehicle, space or device it is protecting, and the receiving device uses that data to authenticate the identity of the fob. This is achieved through symmetric encryption: both the fob and the paired device use the same encryption key to send and receive messages, meaning the fob can be authenticated.
The secured device will only respond to the unique information transmitted by its genuine counterpart fob. Thus, symmetric encryption ensures that only the correct fob can open the space, ensuring access to spaces and data is limited to verified parties.
When you use your key fob to access a device or area, really you’re initiating an encrypted conversation between the hardware in the fob and the hardware in the protected space. Since only the true fob will be able to “unscramble” the message, access it limited to whoever possesses that fob.
Recommended Reading: Interested in learning more about Security? Visit the TechRepublic Academy.
History of the Key Fob
In the modern context, the term key fob is used to describe multiple different devices, including electronic car keys, key cards and even programmable mobile apps. However, the word “fob” originated from watch fobs, which existed as early as 1888, referring to an ornament attached to a pocket-watch chain. Only recently has it evolved to include key chains, remote car starters, garage door openers, and keyless entry devices on hotel room doors.
