It’s been a while since I wrote an “attack of the week” post, and the fault for this is entirely mine. I’ve been much too busy writing boring posts about Schnorr signatures!…
There was a thing called Bump like a decade ago that just disappeared for some reason. Android also had a way to stick phones together and you could just send whatever you had on your screen.
And ever since, sharing between people has become so difficult, nobody uses it. I don't understand why it's had to be this was and that only just now Google and Samsung are getting it together with Nearby Share.
Why not just add a timestamp that rotates every, say 5 seconds, to the hashed data?
That would make it infeasible to precompute the table permanently (it would have to be precomputed for a very narrow attack window, which is still better than nothing)