Ask HN: A Decentralized Proof-of-Aliveness?

Sadly, there have been a fair number of HN posts lately about devs passing away. It's forced me to think about not only my own mortality, but the mortality of my digital infrastructure and other sorts of digital assets/content that ONLY I may own/know (e.g. keys, passwords, etc).

Seems like if we could design some sort of "aliveness attestation" - such that it could be cryptographically verifiable for the purpose of a succession process. Basically making it so that your fiduciaries can execute under RUFADAA [1] would be handy for sure.

But then it sort of dawned on me that that same sort of attestation could be applied to other situations like placing some sort of "mark of meat" onto your online posts, interactions and engagements could be undeniably handy as well - so long as it couldn't be gamed (at least not, "easily").

"Proof-of-Aliveness" is of course a very hard (impossible?) problem to solve ... or is it? Curious what HN thinks could be a viable solution(s) to a problem that so clearly needs a GOOD solution.

[1] https://en.wikipedia.org/wiki/Digital_inheritance#cite_note-11