After the Belfast Project Fiasco, Time For Another Look At Time Capsule Crypto?

JonZittrain (628028) writes "I'm curious whether there are good prospects for 'time capsule encryption,' one of several ways of storing information that renders it inaccessible to anyone until certain conditions — such as the passage of time — are met? Libraries and archives could offer such technology as part of accepting papers and manuscripts, especially in the wake of the 'Belfast Project' situation, where a library promised confidentiality for accounts of the Troubles in North Ireland, and then found itself amidst subpoenas from law enforcement looking to solve long-cold cases. But the principle could apply to any person or company thinking that there's a choice between leaving information exposed to leakage, or destroying it entirely. Some suggested solutions are very much out of the box."

Re:If your encryption is secure, the key is the se

[Ecuador]

Send it on an elliptical orbit around the sun. Depending how many years you want before the key is back in our neighborhood, you select the appropriate orbit. Hmm, perhaps SpaceX should look into it and start commercializing such a service ;)

Do nothing

[Sarten-X]

Most modern cryptography works because it's difficult to solve certain math problems, but the limits of "difficult" keep getting bigger. It should be possible to make a rough estimate of how much processing power will be available to break your encryption by what date, to the parties of interest. Make your keys that strong, and hope you're close.

To build off of the Belfast Project example from TFS, a 50-year timespan might be reasonable. What kind of decryption ability might we have in 50 years? I'm no expert in cryptography, but an elliptic curve algorithm with a fairly-strong key seems reasonable to me. Encrypt it, destroy the plaintext, and forget about it. Forty-five years from now, a government might have the ability to decrypt the material, but they'd have to care, first. It might take sixty years for a data-crunching powerhouse like Google to decrypt it, and perhaps in sixty-five years, they'll see fit to run a PR stunt by unlocking the time capsule.

There's a lot of guesswork and estimation involved, but such is the nature of all time capsules. You're assuming that the capsule will be intact and unlockable at a future time, which necessarily involves predicting future capabilities.

Re:Do nothing

[ZeroPly]

This will not work. "Available power" is not the same for different people. If you devise your key so that you will be able to break it in 20 years on a fast (projected) computer, a distributed project might be able to break it in 3 years. Remember that in 20 years, you want to be able to decode the data relatively easily, you can't assume that you will have 20,000 distributed nodes available.

Re:Lawyer up

[Bill, Shooter of Bul]

This is ,of course, the right answer: laws, not encryption. The smartest people are the ones that examine the entire premise, instead of going along with the implied boundaries of a task.