[leoedin]

The problem is that you have no way of knowing how many copies of the data the hacker has. It's very easy to confirm that the hacker has your data, but confirming the opposite - that the attacker no longer has your data - is pretty much impossible. If there's even a way to do it it would surely involve require the hacker to have encrypted data which can only be decrypted if certain conditions are met. If you're going to go to that length then why not just encrypt it by a conventional means and not risk your data at all?

Unless someone fancies setting up a trusted hacker escrow that acts an intermediary between compromised servers and hackers? That sounds incredibly complicated, highly illegal and unlikely to be trusted by either hacker or hacked though.