Proof of Funds

A friend of mine needs to prove to someone else that they control a certain amount of ether. Is there a standardized process for doing this? I know he can sign a message, but I'm wanting exact wording with clear instructions for both parties. I'm wanting to expand on this article:

Here is the what I'm thinking:

Proving Party:

1) Move X ether to a new account.

2) Sign a message from that new account saying something to the effect of "I, $NAME, have access to the Ethereum account $ACCOUNT. As of $DATE, this account has X ether."

3) Send the message and signature to the verifying party

Verifying Party:

1) Verify the signature with something like This proves they have access to the account. The actual message could be a lie though.

2) Check the balance of the address in the message to verify they actually have the funds.

I think most everyone would be fine using etherscan, but if they want to run a node and do all the verifying with their own clients, that is possible to.

I do want to find a clear way to say that the signature really only proves ownership of the keys and the message itself has to verified separately. I'm not sure if the message should have more things in it that aren't actually proven by the signature. Like having it say "I, $NAME, have sole access to the Ethereum account." Things like that can't actually be verified without trusting a third party and so maybe it shouldn't be included at all.

In my case, the proving party is familiar with cryptocurrency, but this is the verifying party's first major interaction with it. I want to have a system that works for novices on both sides. Thoughts? Have I missed a standard?

Submitted February 02, 2019 at 03:55PM }
via reddit