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What Is a Key Fob Entry System?

November 7, 2023

Too busy to read? Here’s a summary:

  • A key fob is a small, programmable device that provides access to locked areas and objects.
  • A key fob works by transmitting identifying data to an access control system. The system then uses the data to identify the user and decide whether to grant access.
  • The best key fob entry systems employ advanced encryption algorithms and multiple security layers to resist data cloning and ensure that only authorized users can access protected sites.

Have you ever found yourself fumbling with a bunch of keys, trying to find the right one to unlock your office, enter your apartment building, or access a storage area with high-value assets? Well, you're not alone.

Anyone over the age of 40 is likely to know the sound of keys rattling together on a chain.

Mechanical key systems have been around for centuries, but they're hardly the epitome of convenience, and they’re no match for today's world of sophisticated criminal actors.

Enter modern-day access control. In this guide, we'll explain what a key fob access control system is, what signal technologies support it, and why key fobs might be the right solution for the security and workflow challenges at your business or organization.

What Is a Key Fob Entry System?

Definition of a Key Fob and Its Basic Functionalities

At its core, a key fob is a small, programmable piece of hardware that provides access to locked areas and objects.

Key fobs are most commonly used for controlling access through gates, buildings, and rooms, but they can be used in any application that requires secure, restricted access.

Unlike a traditional key system, which requires a mechanical lock and key with matching ridges, a fob interacts electronically with an access control system by transmitting the identifying data the system needs before deciding whether to grant access.

Benefits of Using Key Fobs for Access Control

Enhanced Security

One of the main advantages of using a key fob system is enhanced security. Unlike traditional keys, which can easily be copied, key fobs use advanced encryption protocols to prevent unauthorized access.

Many systems also require multifactor authentication for added security. Systems with multifactor authentication require at least two separate forms of identification. For example, a multifactor entry system may need a PIN keypad entry or a fingerprint scan, in addition to the presentation of an authenticated fob, before granting access.

Administrative Control

System administrators can easily add or remove user privileges as needed, create different authorization rules and lists, create different access levels, and monitor site access by reviewing audit trail data.


Let's face it: carrying around a bulky, clangy party of keys can be a pain. Key fobs are small, lightweight, and easily attached to keyrings and lanyards.

Plus, they can be incredibly easy to use—just tap and go!


Whether you're securing a small office or a large campus, key fob systems are incredibly flexible and scalable. You can seamlessly expand or adjust your system as your needs shift or grow.

Key Fob Components

Internal Components

Inside that tiny piece of plastic we call a fob are several crucial components that make the magic happen.

Microcontroller: This is the brain of the operation. It controls the fob's functions and stores encryption keys that resist hacking and cloning.

Transmitter: This component sends identifying data contained within the fob to an access control reader via electronic signals.

Battery: The battery powers the whole operation. Some fobs have replaceable batteries, while others are rechargeable.

External Components

On the outside of a key fob, you will always find a casing of some type. And you're likely to find buttons and LED indicators.

Casing: Casings keep the internal components of a fob from falling out. Usually made of durable plastic or metal, casings are the skin of your fob.

Buttons: Buttons on key fobs support additional functions. For example, fobs often feature emergency buttons that trigger alarms.

LED indicators: These lights show when the fob is active.

Key Fob Signal Technologies

Radio-Frequency Identification (RFID)

RFID is the granddaddy of key fob technology. It's been around for decades and is widely used in many applications, ranging from inventory tracking to pet identification.

In the context of key fobs, RFID chips store unique identifying data that is transmitted to RFID readers in the form of radio waves.

The main advantage of RFID is its simplicity and reliability, but traditional RFID signals aren’t the most secure method of data transmission, and their use is discouraged at high-security access points.

Near-Field Communication (NFC)

NFC is a high-frequency and more complex type of RFID, and its data is far more secure. Unlike traditional RFID fobs, NFC supports two-way communication with access control signal readers. With two-way communication, the fob and reader are able to authenticate each other before any sensitive identifying data is transmitted.

This extra layer of security complexity makes NFC codes far more challenging to clone or hack than traditional RFID codes.

NFC signal technology today is mostly used by mobile payment systems, but it’s making its way into the world of key fobs as well.


You're probably familiar with Bluetooth as the technology that connects your phone to your wireless headphones.

But did you know it's also used in key fobs?

Bluetooth signals are more complex and secure than traditional low-frequency radio waves. As N. Golmie, O. Rebala, and N. Chevrollier explain in a paper published by the Institute for Electrical and Electronics Engineers (IEEE), Bluetooth signals operate in the high-frequency 2.4 GHz range and leverage a method called “frequency hopping” to reduce interference and improve security during data transmission.


While not as common as the other technologies, infrared key fobs do exist. Much like TV remote controls, they use light waves to communicate with readers.

The main limitation of infrared data transmission is the need for a direct line of sight, but this limitation makes infrared fobs much more secure.

Mammoth Security and Key Fob Entry Systems

The humble key fob is a powerhouse of convenience and security, and our team at Mammoth Security knows all about them and other credential options for modern entry systems, including smart cards, proximity cards, biometric credentials, and smartphone signal technologies.

For assistance planning and implementing a security system tailored to your site’s unique security needs, reach out to our friendly and knowledgeable team today. Schedule your free site survey and consultation with an expert from our team by clicking on our contact button and filling out the form.




The signal technologies that can support key fobs include Radio-Frequency Identification (RFID), Near-Field Communication (NFC), Bluetooth, and Infrared.

RFID is a simpler and older technology that transmits data through radio waves. NFC is a more complex and secure form of RFID that supports two-way communication, making it more challenging to clone or hack.

Key fob entry systems can enhance security through advanced encryption protocols and multifactor authentication. Multifactor authentication requires more than one identity-verifying credential.

A key fob consists of internal components like a microcontroller, transmitter, and battery, as well as external components like casing, buttons, and LED indicators. The microcontroller is the brain of the operation, storing encryption keys and controlling the fob's functions.

The benefits of using a key fob for access control include enhanced security, convenience, scalability, and cost-effectiveness. Fobs and other access control credentials are particularly useful for large-scale operations where traditional keys are impractical.

Key fobs are incredibly convenient as they are small, lightweight, and easy to use. They can be attached to a keyring or lanyard and often require just a simple tap for access.

Yes, key fob systems are highly scalable. They allow for the easy addition or removal of users, the creation of different authorization rules and lists, and monitoring via automated audit trail data.



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