timelock

See also https://github.com/petertodd/timelock and similar projects. There might be a way to combine these two concepts plus ephemeral keys as used in perfect forward secrecy, so that the switching technology isn't a single decision to publish a key, but rather time-locking a share of a Shamir-split secret and constantly rolling it forward as the pings happen -- or letting it run out and reveal enough shares for anyone to decrypt. I think it's really, really hard to guarantee that information has been destroyed, especially in a decentralized system, so you won't have the assurance that information was (1) available to encrypt, then (2) unavailable to anyone because it was destroyed, and then (3) somehow recovered, recalculated, or discovered to once again allow decryption. That feels isomorphic to the problem of time travel. But maybe com

Here is an implementation of the same thing, but tailored toward encrypting Bitcoin private keys. Generalizing shouldn't be too difficult if you're interested: https://github.com/petertodd/timelock Also a good article by Gwern about the same topic: http://www.gwern.net/Self-decrypting%20files

Indeed. As others have noted, one of Gwern's many works reaches the front page of HN every few months - usually for its second or third time. Rather than finding this an annoyance, I enjoy these repeat postings; the ideas of which often represent ongoing community conversations (or spark new ones). If this topic is of interest to you, then you might also enjoy this thread [0] from June, in addition to its home on GitHub [1]. [0] https://news.ycombinator.com/item?id=7847687 [1] https://github.com/petertodd/timelock