> The proof of work (implemented here) is a certain verifiable delay function (VDF) known as "sloth". VDFs are cryptographic primitives which prove that a nontr

> The proof of work (implemented here) is a certain verifiable delay function (VDF) known as "sloth". VDFs are cryptographic primitives which prove that a nontrivial amount of time has passed by requiring a long, serial computation. This computation outputs a proof which can be (relatively) quickly verified. Because the computation is serial, scaling to more computational resources (such as more CPU or GPU cores) does not reduce the runtime. Maybe this sort of thing is a market opportunity for the CPU makers? Add two special instructions, one that iterates a sloth given the seed value, and the final instruction that signs the result cryptographically to prove that it was produced by this model of CPU. Perhaps have hardware rate limiting to prevent overclocking. Another idea would be to monitor CPU uptime and sign the uptime + a challenge. The uptime is cleared after signing. This is more like proof of stake, where we are proving that we dedicated n seconds of CPU ownership, while allowing the CPU to be used productively otherwise.