How do I sign a message with a bitcoin address?
One of the more advanced features of the encryption algorithm used by the Bitcoin protocol is a means to digitally sign an arbitrary message with the private key from a specific address. This allows one to prove ownership of a bitcoin address without disclosing the private key. The signature that is generated can then be used to verify that the message was indeed generated by a specific address.
To sign a message using one of your Coinbase addresses:
- Select Tools from the menu on the left or navigate directly to https://www.coinbase.com/addresses
- Select the "Details" button next to the address you would like to sign with
- From the Details page of the address, select the "sign a message" link
- Enter the message you wish to sign in the "Enter Message" box
- You will see your address signature that will be used to sign the message
- Click the "Sign Message" button
7. You can now provide the message and signature to whomever wishes to verify that you do indeed own the address. The signature generated is unique to your address and the message you provide.
The easiest way to provide this signature is to double click on the signature box, then copy/paste it into a message or email along with the message used to generate the signature.