I'm curious about secret notarization and revocation. Why is that particularly desirable? I guess it would be a poor fit for a blockchain indeed...
You can also often get free notarization at your credit union, public library, local government, church or through your employer.
> Notary services are expensive, and some notaries are corrupt
A blockchain being the place where the act of bureaucracy ends up being stored changes nothing about that.
> OTOH this does seem like a good blockchain application
Exactly. It does at first, because it's about authoritatively storing information, and isn't this what a blockchain is good at? But then you think about how the system actually works and what the requirements are. A blockchain brings you immutable and decentralized storage of peer-validated information. None of these properties are of any value here. We just need a centralized storage that does not forget values by accident, which is basically every other solid information storing system. And most of those are a lot easier to run than a blockchain.
This is where a lot of blockchain concepts seem to break down. In most systems at some point you need to trust the data entered in by humans. But how can the members of the system be sure they can trust other members? Maybe certification or auditing by a trusted third-party? Oh, we're right back to where we started.
Hash the will. Store the signed hash on the blockchain. Then, no one knows what the hash represents until your lawyer reveals the will after you've died.
I don't see what role the blockchain plays here.
[1] and who's to say there aren't multiple signed hashes on the blockchain anyway?
The blockchain places the production of the hashes in time; in this case showing that - all else being equal - this will supersedes any previous wills.
Proving things existed at a particular date is important for contracts, wills, IPR, and such.
It doesn't solve everything, you could have a collusion between relatives and lawyers such that they created multiple blockchain entries. But the blockchain would show, for example, if they did it after the subject had died. The relatives would also need to buy off those running the public blockchain, and not just the deceased's law firm, in order to get a legal attestation -- and audits would show the public servants lied. Auditors can be bought off too, no system involving people is perfect.
> [1] and who's to say there aren't multiple signed hashes on the blockchain anyway?
The timestamping of the blockchain is the use case. If multiple signed hashes exist, the latest one supersedes all the previous.
> What do you gain if the lawyer has to reveal it anyway? If you don't trust the lawyer[1], just give a hash of the document to the people who would be affected.
I'm afraid I don't understand. Who would hold the original text of the document in your plan?
Edit: Nevermind, I see what you mean, here. I see the issue as one of public record. If there was a revision to the will which no one in the family liked, and benefited some estranged cousin of yours who lived in another country, the family and the lawyer could conceivably hide the new will and the fact that you were dead from this cousin. Having it all on the blockchain prevents this.
All hail blockchain as the most amazing non-solution to the problem.
Seriously? Most US banks and credit unions have free notaries for their members. And otherwise is around $5 elsewhere for a simple document.