Screenshot blocking

Screenshot blocking prevents the owner of a computing device from capturing screenshots and screen recordings. Some operating systems such as Android and Apple iOS let app makers block the device owners from capturing screenshots and screen recordings of certain content. This may be done to prevent copyrighted content from being copied, such as Netflix blocking screenshots of the app.^[1] However, some instances of screenshot blocking may be seen as excessive and unnecessary in some cases, thus violating ownership of consumers by unreasonably limiting what they are allowed to do with their devices.

Blocking screenshots is typically a restriction set by individual apps, not something that automatically applies across all apps or devices. Here's how it works, depending on the platform:

On Android, apps can block screenshots using a flag called WindowManager.LayoutParams.FLAG_SECURE. When this flag is set on an activity, it prevents the content from being captured in screenshots, screen recordings, and even in the app switcher (Recent Apps view). This is often used by apps such banking, media streaming services (e.g. Netflix), and secure messengers.^[1][2]

While this was originally intended to prevent banking app content from being captured or broadcast to external screens (miracast, MHL), nothing prevents it from being used arbitrarily.^[3][4]

On the Android developer website, Google encourages app makers to add an option to temporarily allow screenshots:

Note: To provide transparency and user control, consider adding a setting in your app that allows users to toggle this flag.^[5]

At the same time, Google failed to provide a built-in option in Android that would let device owners have the final choice to override this restriction without having to rely on permission from the app.

On iOS, iOS does not give developers an official flag like FLAG_SECURE, but they use workarounds, like displaying sensitive content in a UIView with custom rendering, then hiding or blurring it when the app detects screenshot events or apps going into background or app switcher.^{[citation needed]}

On desktop systems, blocking screenshots is more difficult because users typically have full control over the operating system, and there is no built-in API to prevent screenshots. Third-party tools or system-level protections are needed. Although, enterprise apps may block screenshots using digital rights management (DRM), virtual desktop infrastructure (VDI), or overlay detection / screen capture prevention libraries.^{[citation needed]}

Companies tend to cite the following reasons for blocking screenshots:

• Protecting sensitive information: Apps that handle financial data (banks, payment apps) or confidential documents may block screenshots to reduce the risk of accidental data leaks. Screenshots could be captured and shared without consent, which could expose personal information like account numbers or passwords.

• Content protection and licensing: Media apps (streaming services, e-books, and some news apps) sometimes block screenshots or recordings to prevent piracy or unauthorized redistribution of copyrighted content. Examples include Netflix and Spotify. However, there are legitimate uses such as quotations, which falls under fair use.

• Privacy of other users: Messaging apps may prevent screenshots in certain contexts to protect the privacy of the other party. One such example are "disappearing messages" in WhatsApp.

• Regulatory or contractual requirements: In some industries, companies must comply with legal rules around data protection or digital content licensing, which may include preventing local copies from being made.

On desktop operating systems like Windows and Linux, users have always been able to take screenshots or recordings of whatever is on their screen, without programs being able to block it. By contrast, many mobile apps restrict or disable this feature. This raises concerns because it limits a device owner's ability to fully use their own device. Since a smartphone is personal property, users should retain control over its features, including the ability to capture their own screen rather than having that option dictated by app developers.

Some apps implement screenshot blocking in situations where it is unnecessary. For example, since 2018, Chrome has blocked screenshots while in Incognito mode. It is unclear what this restriction is meant to protect against, given that Incognito browsing already functions by not saving history or web cookies.

There are legitimate reasons to take a screenshot in Incognito mode. Developers may need to capture how a website looks to first-time visitors, or users might want to save information temporarily without adding it to their browsing history. In these cases, blocking screenshots serves no meaningful security purpose and only prevents the device owner from using their phone's features as intended.

Screens can be photographed from an external device. The quality of the image is likely to be lower, but it generally does not prevent someone from being able to reach alphanumerical information such as banking details and text-based messages.

Screenshot blocking and screen recorder blocking makes it more difficult to document bugs and problems with apps, which might discourage users from asking for help in online forums and reporting bugs.

WhatsApp blocked screenshots of profile pictures in 2024,^[6] citing it as a measure to protect privacy.^[7] However, once a profile picture has been uploaded to WhatApp, it is no longer a private image.

The "SECURE" flag on Android is responsible for screenshot blocking and screen recording blocking. However, it has another purpose: It prevents content from appearing on external displays such as HDMI and Miracast.

Screen contents can only appear on an external screens if the smartphone owner has chosen to connect an external screen. If the owner does private stuff, they should disconnect the external screen anyway.

Ways to solve this would be to let the user choose which apps can appear on external displays, or let the user decide whether they want to hide content flagged by the app developers as "SECURE".

The "SECURE" flag is not just used to hide "sensitive" content, but also by streaming service providers to prevent screenshots and screen recordings, even though there are legitimate purposes for it (e.g. fair use doctrine). As a side effect, the user cannot connect their phone to a TV or monitor to watch on a big screen, so they have to hope the TV has native support for their streaming provider.

Another reason cited for screenshot/screen recorder blocking is the narrow possibility that third-party screen recorder apps contain spyware.

Third-party apps can only capture the screen if the phone owner allows them. It would make sense to let the user decide which third-party apps can capture content marked as "SECURE". But the pre-installed screenshot and screen recording tool should never be blocked because they don't contain spyware. If users wish to guarantee that their screen recorder software does not contain spyware, they can utilise open source screen recorders.

In any case, there is no reason to block the built-in screenshot and screen recording tools simply because misbehaving third-party apps may be out there.

Android 14 has added a "screenshot event" and Android 15 a "screen recording event". This allows apps to register when the owner takes a screenshot or screen recording. An online poll shows most users are opposed to screenshot detection.^[8]

• Data lock-in