Giving Upspin a spin

Also *far* higher resource consumption (CPU due to proof-of-work, disk space and network bandwidth due to storing the thing) and probably a very low system-wide maximum transaction rate, at least if blockchains are implemented anything like the Bitcoin one.

Blockchains are not a good fit for this problem. (They look like a terrible fit, actually. Why do you need nonrepudiability of fs operations? Why do you need it so much that you're willing to pay blockchain's enormous costs?)