<p>You can sign a message or export the private key of all the addresses in your wallet, including change addresses.</p>

<p>If you want to have a single message signed by all your keys the only solution I see would be to sign a message with the first key, then sign the signed message with a second key, ad nauseam.</p>

<p>Strictly from an encryption point of view I don't believe it is possible with ECDSA to sign with multiple keys in the same signature, I might be wrong here though.</p>

<p>As you may already have guessed, the most practical solution would probably be to consolidate your funds into a single address and sign a message with its private key. But it has a privacy tradeoff.</p>

CC BY-SA 3.0
2013-02-01T20:55:51.310Z
2013-02-01T20:55:51.310Z
David
<p>I want to prove the total sum of BTC I have access to.  Therefore I think if I use message signing to assert "owned by makerofthings7" in each address, then anyone can compute the total coins in my wallet based on that assertion.</p>

<ul>
<li><p>If we only focus on the encryption part (and not what the QT client permits), what is the most efficient way to prove that I control the funds of many addresses?</p></li>
<li><p>Are all addresses in my wallet that contain coins available for signing &amp; verification?  In particular what happens to the "change" addresses that are dynamically created when sending and receiving Tx?</p></li>
<li><p>Can I have a single signed message that is signed by all the keys in my wallet?</p></li>
</ul>

<wallet><private-key><cryptography><signature><message-signing>
How can I use message signing to prove that I have private keys for many different accounts?
makerofthings7
# How can I use message signing to prove that I have private keys for many different accounts?

(Asked by: username_0 on 2013-02-01)

I want to prove the total sum of BTC I have access to. Therefore I think if I use message signing to assert "owned by username_0" in each address, then anyone can compute the total coins in my wallet based on that assertion.

* If we only focus on the encryption part (and not what the QT client permits), what is the most efficient way to prove that I control the funds of many addresses?
* Are all addresses in my wallet that contain coins available for signing & verification? In particular what happens to the "change" addresses that are dynamically created when sending and receiving Tx?
* Can I have a single signed message that is signed by all the keys in my wallet?

**Tags:** wallet, private-key, cryptography, signature, message-signing


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## 1 answers

### Answer by username_1 on 2013-02-01. Score: 1

You can sign a message or export the private key of all the addresses in your wallet, including change addresses.

If you want to have a single message signed by all your keys the only solution I see would be to sign a message with the first key, then sign the signed message with a second key, ad nauseam.

Strictly from an encryption point of view I don't believe it is possible with ECDSA to sign with multiple keys in the same signature, I might be wrong here though.

As you may already have guessed, the most practical solution would probably be to consolidate your funds into a single address and sign a message with its private key. But it has a privacy tradeoff.


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