How to Sign and Verify a Message with Your Bitcoin Wallet

Besides being the world’s most-used signifier of peer-to-peer integer currency, Bitcoin really contains a utile basal feature: the quality to motion and verify a message 

Using your Bitcoin wallet, you tin securely encrypt a connection by signing it, portion the intended recipients tin besides verify the authenticity of your message. All this is achieved lone with the nationalist and backstage keys of the Bitcoin addresses successful your wallet – you don’t adjacent request to person them funded to usage this diagnostic (you tin person an bare wallet, truthful to speak).

What’s the usefulness of doing this?

When you motion from your wallet (either to o.k. a transaction oregon to motion a message), your integer signature simply proves that you cognize the backstage cardinal connected to the nationalist cardinal (the nationalist cardinal being the Bitcoin code that is disposable to the public). 

Your backstage cardinal is an highly ample drawstring of numbers that allows you to power your Bitcoin wallet. It is utilized successful cryptocurrency transactions to beryllium ownership of the nationalist cardinal (or blockchain address). Think of it arsenic a password, but that you tin usage this backstage cardinal to make integer signatures that tin beryllium easy verified by others without needing to uncover the backstage cardinal itself.

Let america speech astir an illustration of however this tin beryllium precise utile to beryllium your ownership.

UserA wants to nonstop UserB immoderate bitcoin. But UserA volition lone privation to nonstop to UserB’s ain wallet, and not idiosyncratic else’s wallet oregon to an exchange. So UserB provides BitcoinAddressB and signs it. UserA verifies the signed message, proving that UseB is so the proprietor of BitcoinAddressB.

You tin adjacent beryllium individuality with this method, conscionable arsenic Bitcointalk users sometimes bash to unafraid their relationship against theft, by ‘Staking’ their Bitcoin code with a signed connection similar successful this thread. Here is an illustration of however radical tin usage signed messages to retrieve mislaid accounts.

UserC posts a signed connection from their Bitcoin address, and it is stored connected the forum aft being verified by a trustworthy person.

One day, UserC’s Bitcointalk relationship is hacked and the password changed. UserC then reaches retired to the forum admins, signing a connection from the aforesaid Bitcoin address, proving that they are so the rightful proprietor of the hacked account. The thief present successful power of the relationship volition beryllium incapable to beryllium they are the rightful owner, since they don’t ain the backstage cardinal to the Bitcoin code and so, won’t beryllium capable to motion messages from it.

UserC’s relationship password is reset, and his entree restored.

Not each Bitcoin wallets are created equal

Before we continue, 1 enactment connected Bitcoin wallets.

The champion mode to usage Bitcoin is to beryllium the sole controller of your backstage key. Wallets that fto you usage Bitcoin similar this are sometimes called non-custodial wallets since nary 1 is taking custody of the backstage keys (except yourself). When utilized with this benignant of wallet, you request to specify your transaction parameters (for example, the magnitude you privation to send, the code you privation to nonstop it to, the interest you would similar to pay, the inputs you would similar to use, etc.) and past motion your transactions and broadcast them yourself to the Bitcoin web for validation.

It’s worthy mentioning present that not each Bitcoin wallets volition assistance you entree to the backstage cardinal associated with the wallet. Some whitethorn assistance it, but not sole access. Typical examples are the wallets of nationalist services similar crypto exchanges oregon adjacent crypto gaming sites similar Crypto.Games. When you transact with these wallets, you typically lone person entree to the nationalist key, which is the publically disposable drawstring of characters usually referred to arsenic ‘Bitcoin addresses’. When you privation to nonstop Bitcoin retired of these wallets, you really instruct the tract to transact oregon nonstop connected your behalf – truthful they are the ones signing the transactions and broadcasting them to the Bitcoin network. Since you don’t power the backstage key, you won’t beryllium capable to motion oregon verify with this benignant of wallet.

Here are immoderate unfastened root non-custodial wallets that let you to motion and verify messages. This is not a proposal to usage either oregon each of them; you should ever behaviour your ain probe to find which wallet suits you best. Also, ever self-verify earlier you download and usage immoderate of these wallets!

• Bitcoin Core
• Electrum
• Samourai

Great! Now amusement maine however to sign/verify a connection with my Bitcoin wallet!

The process to motion and verify messages volition alteration from wallet to wallet. Generally, you should look for the ‘Sign/Verify’ enactment from the wallet.

For this example, a modular wallet connected Electrum v4.04 is used.

We’ll archetypal motion a connection from the code ‘bc1qm5lut8n4zaud84a26nzqymmvnd5sp3uj2smlth’. It indispensable beryllium an code contained successful your wallet you privation to motion from.

1. Open up and motion successful to your wallet lawsuit (enter your password if you’ve encrypted your wallet. If not, wherefore haven’t you?!).
2. From the Addresses tab, close click connected the code you privation to motion your connection with and prime Sign/Verify Message. Or, from the apical paper bar, prime Tools > Sign/Verify Message and participate the code manually into the Address field.
3. In the container that pops up, simply Enter your connection and erstwhile you’re done, click the Sign button. You volition past beryllium prompted to participate your password (if you’ve encrypted the wallet).
4. When completed, the Signature tract should present person a drawstring of characters. That’s your integer signature! In this example, this is what we get: ‘H0GMnwxdhdxtra5djRTHtY0w6hbZMMD2wT+0BGFjEoH7a9sFbgPFBOMEBbQz68hejMj1Rj9oybIVEaxVD+qj+fM=’
5. Now, if you springiness this accusation to anyone, they tin usage the aforesaid tools to Verify your signed connection by entering each this accusation into the respective fields:
• Message: Crypto.Games is the best. Better than each the rest.
• Address: bc1qm5lut8n4zaud84a26nzqymmvnd5sp3uj2smlth
• Signature: 0GMnwxdhdxtra5djRTHtY0w6hbZMMD2wT+0BGFjEoH7a9sFbgPFBOMEBbQz68hejMj1Rj9oybIVEaxVD+qj+fM=