They could do a bit of research and educate themselves. Understanding how to sign/verify a message is not hardwork, is totally free, and the key here is verify, instead of trusting what another party says.

Will editing a certificate involve a process other than a signed message? How do you plan to verify who an address belongs to?

- Jay -

Proof of reserve or ownership is fine! But the major roadblock you are going to face here is the legitimacy of Bitcoin as an asset. Unless that specific country doesn't see Bitcoin as a legal tender, no banks will consider Bitcoin as a part of your net worth. That is just one scenario and I am sure there will be more.

Your vision is nice. But unless a legal framework is provided by the country, I don't see any reason for it to get considered by the registered financial organisations.

if a business decides to accept bitcoin as payment or collateral for a loan, then they will have access to a wallet(which can verify messages).. so they will know enough about bitcoin to participate by just using most wallets..so not really a problem that needs solving

your not really reinventing the wheel you are just trying to pretend vehicles never had wheels or that people cant understand that vehicles come with wheels.. when they clearly have/do without a problem

Can you give us an example of a country where banks (or the tax authority) would not be consider Bitcoin as an asset? That's definitely not the case here in the USA, and as far as I know it's the same almost anywhere.

The term "legal tender" is wildly misused among Bitcoin hardcores, as most people assume it just means "legal". Bitcoin is legal in almost every country in the world, and there are relatively few restrictions on it in most countries.

"Legal tender" is where a government forces people to accept Bitcoin as payment whether they want to or not, and is actually evil in the context of Bitcoin. You really shouldn't use that term unless you know what it means.

If you read carefully what I wrote, i'm not speaking of payment or collateral. In both cases, indeed, you need to transfert your bitcoin. I'm speaking of proving your weatlh to someone

I don't say it's illegal, i just say that in france, I haven't seen yet an institution consider your bitcoin as assets of your wealth; THey know it exists, they just don't handle it, you can check any bank form here

It doesn't looks good, pretty much like a honeypot.

There are no guarantees that the site is secure and who're "people" who have access to the data, if everyone can access it, this would raise a chance to get robbed. Someone with obvious names will easily being targeted, the criminals only need to know who're the name, face and location, then they search how much coins they have.

If you can't use Bitcoin to apply for a loan in France, it just that France didn't accept Bitcoin as a collateral, as simple as that.

How do you think the BTC users will get advantage of their ownership? Using BTC as a collateral to get a loan or something? I don't think that any lender is going to give them a loan without getting the BTC as a collateral. A proof of ownership(without sending the BTC to the lender) won't work.
Having a public list of proven BTC owners would become a problem, if some criminals/mobsters find out that the people on the list have Bitcoins. Maybe this list of proven and verified BTC owners should be kept secret. Or maybe we don't even need such list. Keeping your BTC wealth a secret is the best thing to do.

And the day day after your loan is approved, you lose all your Bitcoins in a casino.... See my point? Collateral is useless if the bank can't access it.

This will be a gold mine for $5 wrench attacks.

I might have a better idea (although I am generally not a big fan of any sort of technology that involves revealing your bitcoin assets to the public):

Using the master public key, you can theoretically create an ECDSA or Schnorr (doesn't really matter which) signed message for your entire wallet.

Obviously, it will take into account BIP44 derivation schemes, so that only receiving and change address paths are checked.

The item that's going to be signed is the master public key, as well as the number of receiving and change addresses.

For verification, an address is given, and using the master public key in the signature, attempt to BIP32-derive a receiving or change address that matches the input address up to the given limit.

If the address is found to be a part of the wallet, then this is verification that the user providing it does in fact own the wallet associated with all those addresses, as well as any additional addresses that are past the limits without having to explicitly specify them. It can function as a sort of proof of funds.

It does destroy all user privacy though, so I'm not sure how this is ever going to be a useful thing. It would also depend on BIP322 getting finalized. It's moving at a snail's pace so far.