There's this http://people.csail.mit.edu/rivest/RivestShamirWagner-timelock.pdf http://people.csail.mit.edu/rivest/RivestShamirWagner-timelo... which uses repea

There's this http://people.csail.mit.edu/rivest/RivestShamirWagner-timelock.pdf 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.