You’d have to keep track of which proofs you’ve already seen, to prevent re-use. You’d have to make sure the (source, source port, destination and destination p

You’d have to keep track of which proofs you’ve already seen, to prevent re-use. You’d have to make sure the (source, source port, destination and destination port)-tuple is a cryptographic part of the algorithm, to prevent me using the same proof of work for like a million machines. Then there’s the issue of low power and/or battery-powered devices. You want people to be able to use your protocol without draining the battery. But by lowering the computational cost to accomodate that, you’re enabling the bad guys that can afford a fast GPU to go back to abusing the protocol cause the cost isn’t sufficiently high to deter them anymore. And I’m sure there are plenty of other things I haven’t thought of.