Snapchat's (and now Facebook Poke's) main claim to fame is that it lets you send "self-destructing" image messages. Setting aside the debate about the uses of this beyond sexting, the key vulnerability in both apps is the built-in ability to take screenshots. Both take a reactive approach, where you're notified if the recipient took a screenshot, but can't really do anything about it. I was thinki
![Screenshot-proof images via temporal dithering](https://cdn-ak-scissors.b.st-hatena.com/image/square/3d7af6df81fdca3a0f82d25a76ce82b5a1cb2334/height=288;version=1;width=512/https%3A%2F%2Fpersistent.info%2Fweb-experiments%2Ftemporal-dithering%2Fmihai.png)