Using Bitcoin to Sign Contracts, Documents and Emails

[LorenzoMoney]

At the Bitcoin MeetUp in Miami, Charles Evans was talking about how Bitcoin can be used to sign legal documents. Professor Evans said that even though GPG or PGP or whatever it is exists, it really is too hard for some people (including me) to figure out how to use easily, and if Bitcoin is going to grow,  there will be all sorts of business deals which will require some sort of electronic signature. When he said that, I did not really understand the implications of encryption versus signature. So, I played around with signature feature on my Bitcoin-QT wallet. 

Let's say someone wants to do business with me and me with him.  He lives in Argentina and me in Florida. We write out a contract and agree to all the terms, we even agree that binding arbitration will be done by a committee of specialists in international bitcoin trade. We don't care about keeping the contract secret so we don't need encryption. All we need is a verifiable signature.

Bitcoin provides the means for a proveable signature to sign contracts and prove one's identity.

It also provides a way to make sure the contract text is complete and wasn't tampered with.

Write out your contract or text or agreement. Open your Bitcoin-QT wallet. Go to Receve Coins. Click on the bitcoin address you use to identify yourself. Then, click on Sign Message. Copy your text or contract to the big space in the middle, then click on Sign Message. Now, copy the signature that gets generated.

Now, send your original contract text, and the signature, and your public bitcoin address to the person you are doing business with to show them that you signed the contract. Or you have them do this, to show that they signed the contract.

Your business partner, or the arbitration court can verify that that contract is signed merely by using the Verify Message feature of the Bitcoin-QT wallet.

They would click on Verify Message, copy your public address to the correct field, copy the text that was signed to the large space, and then copy the signature to its spot and click on verify message.

The Bitcoin-QT wallet will then verify if the owner of that public address actually signed that particular text.

Basically, Bitcoin provides a way to verify your identity and sign contracts.