Unfortunately, no-one seems to know how to do it. It is a pretty hard problem: issuance tied to proof of work works because the solutions it generates are uniqu

Unfortunately, no-one seems to know how to do it. It is a pretty hard problem: issuance tied to proof of work works because the solutions it generates are unique but machine verifiable. Unfortunately, problems with solutions that fulfill that requirement tend not to be very useful in and of themselves. Edit: this is well beyond my expertise, perhaps someone with a better understanding of information theory can prove the above statement wrong. In that case, I hope they go out and build a crypto of their own!