Bitcoin Forum

Hi All,

ICOs are quite complicated for first-time contributors so I thought I would share my experience.
Most contributors face the same challenges and ask the same questions... One of them being "how to sign a message with my Bitcoin address"?

Here is the (at least one) answer.

Context:
- I used Electrum (portable version) but the procedure should be relatively similar with most wallets that let you control your private keys.
- I tested that procedure with the Windows and Linux versions of Electrum. Sorry Apple users :)
- The private keys used in that example are worthless and I will discard them once that message published. Do not publish/share yours.

Pre-requisite:
You need the the private key of the address you want to sign the message with.
If you need the private key of an address in a Blockchain wallet click here https://bitcointalk.org/index.php?topic=2517669.0 (https://bitcointalk.org/index.php?topic=2517669.0).

  1. Download and install Electrum https://electrum.org/ (https://electrum.org/)

  2. Create a new wallet (default type)
https://ibb.co/fDxLfG

  3. Import the address you want to sign the message with. The address has to be added to the wallet you have just created in step #2 as it needs the private key to sign the message.
https://ibb.co/iKvj7w

  4. Once the address available in your wallet click on "View > Show addresses" (the path might differ slightly depending on your OS/the version of Electrum)
https://ibb.co/cQpNub

  5. Fill the form:
    - Message is whatever you want to send to prove you are the owner of the address. Typically a username or an email address.
    - Address is the Bitcoin address you want to sign the message with (should be populated by default, type it otherwise)
    - Signature is generated from your message and the address' private key.
    Note: Any changes to the message will invalidate the signature. If you want to modify the message you will have to generate a new signature.
https://ibb.co/cZ5vEb

That's it you can now send the message, the address and the signature to whoever requested it. It is safe to do so as it does not contain any private key or sensitive information that could give access to your wallet.

Useful tool: You can verify the message / signature here: https://tools.bitcoin.com/verify-message/ (https://tools.bitcoin.com/verify-message/)

That's it.

I hope it helps.


** Disclaimer: I provide the information above as-is without any guarantee **