The H.A.C.K.E.R. Project

Have you ever worried that someone is looking at your device’s screen while in public? Do you have a nosy coworker, roommate, or family member who is always trying to take a peek at your screen? This is actually a type of cyber attack known as “shoulder surfing”, and, depending on the shoulder surfer’s motive, can cause quite a headache for the victim. Fortunately, there is a useful piece of hardware that you can purchase and put onto your phone, laptop, or even desktop computer to make it much harder for a curious individual to see what is on your screen: a privacy screen filter.

How Do Privacy Screen Filters Work?

A privacy screen filter is “a thin piece of plastic that’s placed over your monitor or display panel in order to prevent wandering eyes from absorbing confidential information” (Nelson). It, essentially, is just like a screen protector that you can attach to your device’s screen. However, privacy screen filters come with an extra feature: micro-louvers. Micro-louvers are extremely thin slats that are built in to the screen filter that provide privacy. Micro-louvers are “similar to vertical [window] blinds, which can only be seen through when they are turned at a certain angle” and they work by “severely restricting viewing angles to the point where you essentially have to look at the screen straight on in order to see the display” (Nelson). Furthermore, the micro-louvers “control the amount of light that reaches your eyes, creating a darkened effect for those outside the optimal viewing angle” (Lenovo). That way, unless you are sitting directly in front of the screen, your view will be obscured by the micro-louvers in the privacy filter. This can help prevent shoulder-surfers or nosy people from seeing what is on your screen, especially since they would have to position themselves directly behind you in order to get a decent view of the content on the screen. As a result, privacy screen filters “can be particularly useful in crowded places like coffee shops, airports, or offices where people might try to glance at your screen” (Lenovo).

Installing a privacy screen filter is relatively straightforward. In most cases, “you attach the screen to your device using adhesive strips or slide it into place”; however, it is “essential to align the screen correctly and make sure it covers the entire display area” (Lenovo). Due to how the micro-louvers are positioned, an improperly-placed privacy screen filter could make it difficult to view your screen from in front of it, or it may not work as well as intended. Thus, make sure the privacy screen filter is aligned properly before fully securing it to the device. Alternatively, if you are in the market for an entirely new device, “you can now find computers with a laptop privacy screen built in, so you would not need to purchase an additional filter to conceal your display content” (Nelson). These such devices often come with a switch or setting that allows you to toggle the privacy screen filter on and off as you desire.

Why Should I Use a Privacy Screen Filter?

Privacy screen filters, as stated before, have one primary benefit: they are “designed to prevent shoulder surfing, which refers to someone intentionally or unintentionally looking at your screen over your shoulder” (Lenovo). Since they obscure the information on the screen unless looking at the screen directly, privacy screen filters strictly limit a shoulder surfer’s ability to see what is on your screen, helping to add another level of security to your data. While “strong passwords, anti-virus software, data encryption, and heightened awareness go a long way toward keeping your information secure”, they unfortunately “can’t defend against visual hacking” or shoulder surfing, which is why a privacy screen filter should be taken into consideration (Nelson).

Unfortunately, plenty of information, both confidential and otherwise, is “vulnerable to visual hacking in both onsite and remote work environments. While you may want to give everyone the benefit of the doubt, the truth is, unfortunately, that the stranger sitting to your right on a train or the custodian walking past your door should not be trusted” (Nelson). Overall, the consequences of being shoulder-surfed vary depending on the hacker’s motive; they “can be as mild as annoying junk mail and telemarketing calls, or as severe as life-altering identity theft” (Nelson). As with most cybersecurity decisions, it is better to be safe than sorry. Furthermore, “if you often travel for work, you probably use your laptop and other devices in public spaces like restaurants, parks, trains, or airports. Hackers are likely to frequent these locations looking for easy targets”, which is why it is extremely important to protect yourself while in public spaces (Andriekutė). Hackers may attempt to steal confidential company data via shoulder-surfing, which could not only harm the company, but also your career.

However, it is important to keep in mind that privacy screen filters, like many cybersecurity techniques, are “not a foolproof solution. The degree of privacy depends on the quality of the screen protector and the viewing angle. Also, they don’t prevent someone from seeing your screen if they’re standing directly behind you” (Andriekutė). Thus, it is still important to maintain situational awareness whenever using a device in public. For example, sitting with your back against a wall can help prevent anyone but you from looking at your screen from a direct angle. Remembering to lock your device if you leave it unattended is also another great way to boost the cybersecurity of your device.

Aside from preventing prying eyes from reading your screen, a privacy screen filter may also come with additional built-in features that you may find useful. For example, some privacy screen filters have an anti-glare feature built in to the material and others come with blue light filters to reduce the amount of blue light that reaches your eyes, similar to blue light lenses (Andriekutė). Additionally, some privacy screen filters also provide some protection to your device screen, much like a standard screen protector. However, it is important to note that one primary downside of a privacy screen filter is that it “may reduce the brightness of the screen”; as a result, you may need to increase your screen’s brightness which will in turn drain the battery faster (Andriekutė). However, the security benefits of a privacy screen filter, in many cases, outweigh this detriment.

What Type of Privacy Screen Filter Do I Need?

There are a variety of different privacy screen filters available to purchase and attach onto your device. Thus, it is important to weigh your options before committing to purchasing a specific privacy screen filter. Some filters might, as mentioned above, come with extra features, which may increase cost, while others may have a more restrictive viewing angle. Andriekutė from NordVPN provides a useful list of items to consider when purchasing a privacy screen filter:

• Degree of privacy. Different screen protectors offer varying degrees of privacy based on the angle of view they allow. Some provide a 30-degree angle of view, while others offer up to 60 degrees. Consider the environment you’re most likely to use it in and how much privacy you need.
• Device compatibility. Carefully check whether the protector is compatible with your device. Screen protectors are usually designed for specific models to ensure a perfect fit. Buying according to the display size will likely not work because different devices can have thicker or thinner frames, which will change the size of the screen protector you need.
• Screen clarity and brightness. A good privacy screen protector shouldn’t affect the quality of your device’s display too much. You will have to sacrifice some brightness, but make sure your device is still usable in all kinds of lighting.
• Touchscreen compatibility. If you’re using a touchscreen device, ensure the privacy screen protector is compatible and won’t make the screen unresponsive.
• Installation and removal processes. Some protectors are easier to install and remove than others. Consider whether you’ll be frequently removing and reattaching the privacy screen and choose accordingly.
• Additional protective features. Depending on your needs, you should look for features like scratch resistance, impact protection, anti-glare, UV and blue light reduction, and antibacterial properties.
• Price and quality. As with every purchase, you want to get the most bang for your buck. So while you make sure you’re not overpaying (the most expensive option is not always the best), keep in mind that cheap privacy screens will not protect your sensitive data as well and might break quickly.

Andriekutė

Each of these seven points should be carefully considered before you purchase a privacy screen filter, especially device compatibility. That way, you can ensure that the filter not only works with your device, but is suitable for all of your cybersecurity needs!

Resources & Further Reading

Andriekutė, Aurelija. “What’s a Privacy Screen Protector, and How Does It Work? | NordVPN.” Nordvpn.com, Nord Security, 11 Aug. 2023, nordvpn.com/blog/how-do-privacy-screens-work/.

Lenovo. “Why Should You Use a Computer Privacy Screen & Are They Reusable? | Lenovo US.” http://www.lenovo.com, www.lenovo.com/us/en/glossary/why-do-i-need-computer-privacy-screen/.

Nelson, Kaelee. “Why Do I Need a Computer Privacy Screen?” Hp.com, HP, 11 Jan. 2019, www.hp.com/us-en/shop/tech-takes/why-do-i-need-computer-privacy-screen.