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Comment by sandis | Hacker News Reader

App hides the content as soon as you try to take a screenshot and it notifies the sender of your attempt.

Maybe on Android, but iOS does not have the [public] APIs to allow for that. There used to be a notification called PictureWasTakenNotification that was fired after a picture was taken, but that disappeared in iOS 5.

Snapchat notifies of a screenshot, but the screenshot can still be taken. The theory is Snapchat checks the photo album count and if there's an additional photo it assumes a screenshot and will notify the other party.

Here's a discussion on the topic:

http://stackoverflow.com/questions/13484516/ios-detection-of...

No, you can easily block taking a screenshot, as long as (and as with Facebook Poke and Snapchat) you require a finger on the screen. I explain it here: http://blog.chpwn.com/post/38491252231

Are you saying that it's possible but both Snapchat and Facebook failed to figure it out? I just took a screenshot of images I received on both services and the screenshots certainly worked.

In iOS, an app can detect if you press the home button and lock button simultaneously to take a screenshot?

Like any DRM this is easily defeated. I could run the app in a virtual machine and take the screenshot from the hypervisor or host machine instead. Or I can capture the network traffic. Or I can take a photo of my phone. And so on and so on.

The "take a photo of my phone" is the one that non-geeks can easily remember to do. And they will.

And I imagine on any phone with a face-facing camera (would that be "forward facing", or "rear facing"?) doing that with another application and a portable makeup mirror should be trivial.

All you need is an application that takes a picture without altering what is on the screen when you press both volume buttons, or something. Maybe even just takes a picture once a second for the next 30 seconds?

You could make an application explicitly for this purpose, and even build in the mirrored image logic. Only one person needs to do it, then every non-technical user can use it.

Ugh, seriously? DRM? Come on, it's a fun app for friends to send embarrassing pictures of themselves to each other. Obviously there's an "analog hole", but this isn't for incredibly confidential photos.

It is in the best interests of the prospective non-technical users for the ease of exploiting the analog hole to be well known and fully comprehended.

Knowing that nerds can break it isn't enough, the users need to understand that their 14 year old peer with no technical skills can also break it, without breaking a sweat.

The point with these apps was to make sexting safer (I'm just going to say it straight out). Not completely safe. If you are sending pictures of your junk to another person, you are always exposed to the risk of getting backstabbed. Same goes if you put a person's junk in your mouth, or some similar behavior.

A degree of trust is required in all relationships, but at least apps like these remove some of the incentive for abuse. And they make it impossible for someone to _inadvertently_ share your photos.

That is what I assumed the point was. If that is what people are using it for, that's fine, but I think that makes it incredibly important that they understand the technical solution to what is ultimately a social problem is imperfect. The technical imperfections are fine, so long as the users are fully informed and are not being mislead in any way.

(And since sex drive is involved here, meaning there is a pretty strong incentive for laymen to go after the analog hole, it is especially important that people are made fully aware of the limitations.)

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