6 ms·

It is actually astonishing to me that this is not something which can be turned off at the OS level, or as a permission setting in the app permissions. The app

It is actually astonishing to me that this is not something which can be turned off at the OS level, or as a permission setting in the app permissions. The app knowing I took a screenshot feels adjacent to me to a keylogger. Imagine how many apps are capturing that information silently. To my mind, a screenshot is something that is happening outside of the app context, the app knowing about it is a security flaw imo.

dc443 2mo ago
but you didn't read the part where the mechanism is explained? it doesn't do anything like capturing information. it just marks a button "sensitive" causing it to be hidden in a screenshot, thus revealing an icon that was put there underneath the button.
araeyn 2mo ago
Did you read the article? Bluesky doesn't know you're taking a screenshot, iOS just hides the follow button in the screenshot (consequently making the Bluesky logo visible).
- LPisGood 2mo ago
  iOS does tell the app that a screenshot was taken though
- verdverm 2mo ago
  > Please don't comment on whether someone read an article. "Did you even read the article? It mentions that" can be shortened to "The article mentions that". Found in the HN commenting guidelines, linked at the bottom of most pages
  - araeyn 2mo ago
    Noted, I'll keep that in mind when commenting in the future.
CircuitSeuss 2mo ago
> The app knowing I took a screenshot feels adjacent to me to a keylogger. To my knowledge, this is a misunderstanding. The app does not know that you are taking a screenshot, rather iOS knows you are taking a screenshot (as it must) and is excluding an element on display that has been designated by the developer as sensitive information. This is the same technology that prevents you from accidentally screenshotting your password manager; the developer has simply performed a nifty trick to display a small icon behind where the “follow” button would otherwise be displayed. There are plenty of instances where this sort of thing can be annoying, such as when you try to screenshot a streaming service app and DRM enforcement leaves you with a blank screenshot, but IMO this particular instance is actually very tasteful; seeing “follow” on every screenshotted post is just useless noise, but a small unobtrusive platform icon is a useful reminder that the post came from Bluesky and not another very visually similar service like X(cancel) or Mastodon.
- Barbing 2mo ago
  Can Snapchat no longer inform the other user when a screenshot was taken?
  - jambalaya8 2mo ago
    can someone just take a picture of the phone with another phone, or use a screen recorder?
    - computably 2mo ago
      Security is never absolute, it always "merely" raises barriers.
      - jambalaya8 2mo ago
        [flagged]
        Barbing 2mo ago
raincole 2mo ago
> The app knowing I took a screenshot feels adjacent to me to a keylogger. That is what this article is about and why you should read it before commenting. The whole point is that it doesn't need to know you're taking screenshots. That's why it's a clever trick.
- echoangle 2mo ago
  But for completeness, iOS apps can detect screenshots. That’s what allows them to show annoying popups with a share option when you take a screenshot.
  - edoceo 2mo ago
    What? App-B on iOS knows when I'm taking a screenshot from App-Y? I don't have iOS to check but that seems crazy.
    - efskap 2mo ago
      I guess it would need permissions, but you can monitor the photo library with PHPhotoLibraryChangeObserver and check if a new item's subtype is photoScreenshot. Otherwise userDidTakeScreenshotNotification only fires for your own app
    - echoangle 2mo ago
      No, I was talking about App Y knowing about a screenshot you take of App Y. Isn’t that what everyone is talking about?
      - albedoa 2mo ago
        Yes, that commenter is lost.
    - KennyBlanken 2mo ago
      Yes, as does android. https://developer.apple.com/documentation/uikit/uiapplication/userdidtakescreenshotnotification https://developer.apple.com/documentation/uikit/uiapplicatio...

dc443 2mo ago

but you didn't read the part where the mechanism is explained? it doesn't do anything like capturing information. it just marks a button "sensitive" causing it to be hidden in a screenshot, thus revealing an icon that was put there underneath the button.

araeyn 2mo ago

Did you read the article? Bluesky doesn't know you're taking a screenshot, iOS just hides the follow button in the screenshot (consequently making the Bluesky logo visible).

LPisGood 2mo ago
iOS does tell the app that a screenshot was taken though
verdverm 2mo ago
> Please don't comment on whether someone read an article. "Did you even read the article? It mentions that" can be shortened to "The article mentions that". Found in the HN commenting guidelines, linked at the bottom of most pages
- araeyn 2mo ago
  Noted, I'll keep that in mind when commenting in the future.

CircuitSeuss 2mo ago

> The app knowing I took a screenshot feels adjacent to me to a keylogger. To my knowledge, this is a misunderstanding. The app does not know that you are taking a screenshot, rather iOS knows you are taking a screenshot (as it must) and is excluding an element on display that has been designated by the developer as sensitive information. This is the same technology that prevents you from accidentally screenshotting your password manager; the developer has simply performed a nifty trick to display a small icon behind where the “follow” button would otherwise be displayed. There are plenty of instances where this sort of thing can be annoying, such as when you try to screenshot a streaming service app and DRM enforcement leaves you with a blank screenshot, but IMO this particular instance is actually very tasteful; seeing “follow” on every screenshotted post is just useless noise, but a small unobtrusive platform icon is a useful reminder that the post came from Bluesky and not another very visually similar service like X(cancel) or Mastodon.

Barbing 2mo ago
Can Snapchat no longer inform the other user when a screenshot was taken?
- jambalaya8 2mo ago
  can someone just take a picture of the phone with another phone, or use a screen recorder?
  - computably 2mo ago
    Security is never absolute, it always "merely" raises barriers.
    - jambalaya8 2mo ago
      [flagged]
      - Barbing 2mo ago

raincole 2mo ago

> The app knowing I took a screenshot feels adjacent to me to a keylogger. That is what this article is about and why you should read it before commenting. The whole point is that it doesn't need to know you're taking screenshots. That's why it's a clever trick.

echoangle 2mo ago
But for completeness, iOS apps can detect screenshots. That’s what allows them to show annoying popups with a share option when you take a screenshot.
- edoceo 2mo ago
  What? App-B on iOS knows when I'm taking a screenshot from App-Y? I don't have iOS to check but that seems crazy.
  - efskap 2mo ago
    I guess it would need permissions, but you can monitor the photo library with PHPhotoLibraryChangeObserver and check if a new item's subtype is photoScreenshot. Otherwise userDidTakeScreenshotNotification only fires for your own app
  - echoangle 2mo ago
    No, I was talking about App Y knowing about a screenshot you take of App Y. Isn’t that what everyone is talking about?
    - albedoa 2mo ago
      Yes, that commenter is lost.
  - KennyBlanken 2mo ago
    Yes, as does android. https://developer.apple.com/documentation/uikit/uiapplication/userdidtakescreenshotnotification https://developer.apple.com/documentation/uikit/uiapplicatio...