Wallet signing guide
BTC wallets have an intersting feature of message signing. Thanks to the underlying crypto, it is possible to prove a particular piece of data ("the message") came from you and not someone else.
BTC wallets generally fall into 2 categories: programs you install on your PC (or smartphone/tablet) which accesses the blockchain directly, and third-party online services, that handle blockchain transactions for you.
In either case, a BTC wallet should have the message signing (and verification) feature provided somewhere in its interface.
Typically, message signing interface contains 3 pieces of data:
- Wallet address
For your wallet address, you should (obviously) use the address you would like to receive payments on.
The message will be provided by our system, just copy & paste it to your wallet program (or provider).
It is up to you to generate the signature using your wallet program (or provider). After you do, copy & paste it back to our website, and press "Save".
NOTE: bitcoin message signatures come in several different formats,
however the most popular is the
bitcoin-qt format, used by the original
bitcoin client. That's the format we use too.
There are dozens of wallet programs and houndrets of online services, and this guide can't possibly cover them all. We do have hints for some of the most popular, though.
bitcoin-qt (recently renamed into "Bitcoin Core"), is the original, and probably most popular bitcoin wallet software. Most other programs and platforms follow its message signing format.
Select "File" in the main menu, and click "Sign message...".
electrum is "light-weight" wallet, meaning it doesn't handle the whole blockchain by itself, relying on third-party services instead. It uses the same signature format as bitcoin-qt.
Select "Tools" in the main menu and click "Sign/verify message".
multibit is another rather popular wallet program. The signature format is compatible with bitcoin-qt.
Select "Tools" from the main menu and click "Sign Message".
blockchain.info is arguably the most used web-based wallet service.
To sign a message with it, follow the instructions from their FAQ.
On the "Receive Money" tab, click on the "Actions" drop-down, and from that menu, choose "Sign Message".
It uses the same signature format as bitcoin-qt (which is a good thing).
coinbase.com is another popular wallet provider, with a built-in exchange.
To sign a message with it, follow this article from their FAQ section.
XAPO is a popular and secure wallet. Unfortunately, you can not sign a message using XAPO (nor do they provide private key export, which would've allowed you to sign it using external tools).
XAPO is missing a crucial bitcoin feature! If it's important to you, we recommened contacting them and nagging about implementing that feature.