The reduced power requirements of proofs of space, which is one of its core features, opens it up to grinding attacks, in which an attacker tries many different possible histories at once and selects the most advantageous one. I'll explain how through extensive use of canonical primitives, the addition of verifiable delay functions, and careful hooking of everything together, it's possible to get grinding attacks under control.
The Stanford EE Computer Systems Colloquium (EE380) meets on Wednesdays 4:30-5:45 throughout the academic year. Talks are given before a live audience in Room B03 in the basement of the Gates Computer Science Building on the Stanford Campus. The live talks (and the videos hosted at Stanford and on YouTube) are open to the public.