Angry Mob Cryptanalysis

The key escrow debate appears to be over (and we seem to have won, or at least the government hasn't mentioned it lately), but here's a half-baked solution to the problem that I proposed a few years ago.

Split up your key with a "threshold secret-sharing" scheme that creates, say, 5000 shares where any 500 of them can be put together to reconstruct the key. Send one share to each of 5000 randomly selected people on the 'net (who presumably have some kind of server set up for dealing with this). Don't write down who you sent the shares to.

If you need to recover your key, broadcast a message to the entire world that says "Hey, I need my key back. Anyone with shares, please send them to me". Once 500 of your original 5000 shareholders respond to the broadcast, you've got your key back. (Maybe offer a reward to encourage responses).

The point of all this is that while anyone can recover a key, no one can do it *secretly*. Law enforcement could also get keys to decrypt suspected criminals' files, but only in a way that's open to public scrutiny.

There are a bunch of details needed to make this work; some of them were worked out in my paper at the First Cambridge Information Hiding workshop in 1996. I've linked to it in the links section, below