[gill984]

Link to HN post? I can't find it searching for "Alrawi" or "ISIS encrypt".

[mikeash]

Here: https://news.ycombinator.com/item?id=10916731

I believe the title was changed afterwards to better reflect the article's content. You can see lots of comments that think it's a chat app.

[jacquesm]

https://news.ycombinator.com/item?id=10916731