How would I prove that I own X amount of Bitcoin to somebody without violating my privacy or sending/risking any coins? Now that people who own a full Bitcoin will be like people who currently own ten million USD or more in &quot;liquid assets&quot;, I'm trying to come up with some way that I can safely and reasonably prove to somebody that I own X amount of Bitcoin. Being able to cryptographically convince somebody that you control (have the private keys to) a certain sum of Bitcoin (or &quot;over X amount&quot;, to conceal your full wealth) will probably be very important in the near future. I want to prepare for that situation.
If I simply tell somebody that I own X BTC, why should they believe me? I realize that this same goes for fiat money as well. How many attractive females have not been lied to by some guy in a fancy suite who claims to have &quot;ten mills&quot; on the bank, but really is all broke and barely was able to afford the clothes he is wearing?
But Bitcoin is still seen by many as some kind of &quot;joke&quot; or &quot;fake money&quot;. So I would have to prove it for sure for them to even speak to me. And if this requires doing scary operations in Bitcoin Core and possibly ending up revealing your private keys or other sensitive data... well... I don't even understand how a normal person would be able to verify your cryptographic &quot;key&quot; or whatever form this takes. They are just not going to bother with that.
In summary: how do I prove to somebody that I own and exclusively control X amount of Bitcoin, in a way which non-computer hackers can comprehend, yet does not rely on some kind of &quot;traditional bank&quot; or third-party commercial service?
For example, those who went on those &quot;Bitcoin rich people&quot; cruises, how were they verified to actually own a bunch of Bitcoin? Can anyone just claim to own X BTC and they will believe you? I don't get how this is done.
The way that this is done is to sign messages using the private keys which correspond to your UTXOs. Your UTXOs are what make up your Bitcoin balance, and by signing a message with the keys associated with them, you are proving that you have the ability to spend those UTXOs.
To verify, someone can verify the signed message, compute the addresses for the keys you used, and then lookup the addresses and see how much Bitcoin are associated with all of those addresses.
For the average person, there is software that can verify the message for you and they will return what address was used in signing that message. Then they can just take this address and look it up on a block explorer.