[jpalomaki]

It would be cool if there was a relatively reliable way of creating cryptographic "time capsules" that can be only opened at certain date in future.

So something like, I encrypt message with a certain public key. The private key is guaranteed to only become available on 1st of January 2030.

[Moodles]

There's this http://people.csail.mit.edu/rivest/RivestShamirWagner-timelo... which uses repeated squaring as a kind of unparallelizable searching function to force a set period of time until a solution is found.

I wonder if you could perhaps do a kind of Shamir secret sharing scheme where as long as most of the participants are honest, they all agree to piece together their shares of the secret at the specified time.

[smilliken]

Maybe someone else can find it, but scottaaronson.com has an article that describes a scheme where there's a cheap computation that has to be done serially, so anyone can open if it they crunch cheap hashes for the requisit amount of time. The cleverness in the construction is that the creator gets to skip this work.