[dsl]

That is effectively a proof of work scheme, which is what most time lock systems are based on. The fundamental problem is that people with more resources can decrypt faster than people with less resources, and you're generally wanting to share with someone who has less not more.

[chrislipa]

You make a good point, but that's also a shortcoming of all of the purely computational techniques. I think the most you can hope for is 'democratizing' the computational methods, i.e. making them non-parallelizable.

Taking gwern's idea, what if the homomorphic computation is just incrementing your input repeatedly inside of a loop? It seems like that might be hard to parallelize. Or at least, I don't know enough to assume otherwise.