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By Fredrick Njoroge


Communication has indeed evolved. We learnt of the traditional means of communication: smoke, fire, messengers, etc. With technology came wired/cable communication: telephone, telegraph, etc. And finally, wireless…

Wireless is widely used today, as it gives a user the freedom to move around while connected (portability). Wireless technologies are continuously being improved, from cellular (1G to 5G, and counting) to Wi-Fi (now at Wi-Fi 6), etc.

However, wireless technologies have inherent vulnerabilities, and are prone to attacks if not properly secured.

This article seeks to give a considerably basic overview of the common wireless technologies we use on a day-to-day basis and propose ways in which one can be secure while using them.


Cellular (Mobile)

Cellular networks are all around us. A mobile network operator (MNO) is responsible for setting up the infrastructure on masts and ensure that signal coverage is good.

A client connects to the network by acquiring a mobile device and a SIM card. The SIM card has the phone number as its unique identifier. The mobile device also has a unique identifier and may be used to track fake devices or devices used in crime.

Services offered by the MNO include voice (calls), SMS and data. Voice and SMS are available on every device, but data is available for devices that can connect to the Internet.


Wi-Fi refers to a wireless local area network (WLAN). It allows for Internet connection or rapid file sharing.

Recently, the number of Wi-Fi networks has increased to provide high-speed Internet almost everywhere. The Internet is availed to a Wi-Fi router via a fibre optic cable, and the router can provide the Internet wirelessly (Wi-Fi).

Usually, Wi-Fi services are paid for on a monthly basis. Clients pay for a certain speed/bandwidth (say 1 Mbps, 100 Mbps, etc.).


Bluetooth belongs to a family known as wireless personal area networks (WPAN). Bluetooth allows for interconnection between multiple “smart” devices that belong to an individual (watches, home appliances, audio, etc.). It also allows for file sharing, albeit slower than Wi-Fi.

Recent Bluetooth versions (4.x, 5.x) provide more secure and stable connections with higher speeds.


Here are a few recommendations to guarantee your safety and security on each of the three technologies:

  1. Cellular (Mobile)
    • Most of the time, the service provider of the cellular network has taken necessary measures to protect its clients. However, the client may fall prey to attackers and lose data and money.
    • Avoid clicking on links shared via SMS, email, or any Instant Messaging (IM) apps. The links may redirect you to an attacker’s server and lead to the loss of your personal data or even money.
    • “PIN yako, siri yako!” Do not share your PIN or any other details to a person purporting to be your service provider.
    • Do not entertain calls or texts from strangers. Hang up as soon as you suspect that you have been called (or texted, for that matter) by a stranger, and report to the relevant authorities.
      • For Safaricom, send a message to 333 with the phone number of the stranger being the message body.
    • Keep your SIM cards safe. In case of theft or misplacement, contact your service provider to block it immediately.
    • Calls made using apps such as WhatsApp are more secure than those made using your SIM card; use the former if you can!
  2. Wi-Fi
    • Avoid connecting to public/free Wi-Fi. If you must, use a Virtual Private Network (VPN) to secure your connection.
    • Turn off your Wi-Fi when not in use. Your device may automatically connect to a rogue network.
    • WPA-2 (or WPA-3 for Wi-Fi 6 enabled devices) is the safest protocol to use when creating a hotspot using your mobile device.
      • When setting up your hotspot, there are other options, namely:
        • Open: No password required for connection
        • WEP
        • WPA
      • These protocols are weaker in nature than WPA-2.
    • Change the default settings on your router.
      • Passwords (admin, Wi-Fi)
      • SSID (aka the network name)
      • Do not have your name (or any other details such as house no, office no.) as your SSID. This may be used against you for criminal purposes.
    • Hide your SSID to make your network inaccessible to those not meant to connect to it.
    • Set up ‘Guest Wi-Fi’ if your router allows you to.
      • This prevents other users from accessing your devices connected to your network.
    • Recommendations for a standard password:
      • Minimum of 8 characters
      • Include uppercase and lowercase letters, numbers and special characters (e.g. !, @, #, $, %, ^, &, *, _)
      • Do not have two or more characters repeated sequentially (e.g. ooo, 11)
      • Should be easy to remember
      • If your router allows, you may include spaces i.e. you may set up a phrase or sentence for your password.
    • To block certain devices or allow specific ones, use MAC address filtering.
      • Whitelisting: This type of filtering only allows devices whose MAC addresses are listed to connect to the network.
      • Blacklisting: This type of filtering blocks access to the devices whose MAC addresses are listed.
    • Admin access to the router may be restricted to being performed via cable (Ethernet connection) only. This is done by disabling (admin) access via Wi-Fi.
  3. Bluetooth
    • The best way to secure your device is to turn off Bluetooth if not in use.
    • Avoid Bluetooth at all costs. If you have an option to connect two devices using other wireless technologies (Wi-Fi for instance), prefer it over Bluetooth.
    • Change the default pairing PIN code of your device (if you can; most devices do not have this option).
    • If possible, get a device with the latest versions of Bluetooth (4.x onwards is recommendable).
  4. Other recommendations
    • Avoid storing passwords, payment details and any other personal information on your mobile device.
    • Ensure that your device (mobile phone, router, etc.) has its software and firmware up to date. Always check for updates.
    • Install apps from verified sources only.
    • Ensure to key in your passwords, payment details and any other personal information whilst nobody is looking.
    • Regularly change your credentials.
    • Turn off your location (GPS, GLONASS, etc.) when not in use.


It is important to practice safety and security while using wireless devices and networks. Such are the most vulnerable because data is transmitted over the air; the “air” is accessible to anyone and everyone. Stay safe wirelessly!

Wireless technology is evolving at a super high rate. It is advisable to arm yourself with knowledge of emergent technologies (e.g. 5G, Wi-Fi 6) to learn of their benefits over former ones, and their security challenges/issues.

[P.S.] Here is a survey paper on cryptographic methods used in mobile technologies: A Survey of Cryptographic Methods in Mobile Network Technologies from 1G to 4G

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