BlockSign

You can now see your Bitcoin address on Blocksign.

If you sign in to Blocksign, you can now click your name in the top right corner of the site, and a dropdown will appear. That’s where you will find the  Bitcoin address that we’ve created for you and that is used in the process of storing records of your signed documents in the Bitcoin blockchain. It’s kind of like your phone number in a new phone book. It’s something that people can use to look you up.

We have acquired the blocksign.com domain.

We’re of course very excited to now have the keys to the domain that fits our brand. We had a very pleasant and reasonable experience acquiring the domain from its prior owner.

Signatures are strange beasts. They are powerless by themselves, but through surrounding social norms we entrust them with immense power. You put your palm impression, your fingerprint, or an X mark on some document. You swear an oath and let your blood into a chalice. Or you hash a pdf and encrypt the hash with your private key! All of these serve one purpose: To express, in a socially accepted and unambiguous manner, that you give your deliberate consent to some agreement, document, statement, or contract. Signatures turn an ‘uhm sure, i guess’ into a strong and clear ‘yes’.

Since neither blood oaths nor ink marks are of much use through the Internet, however, we need something better. This is where BlockSign comes into the picture. Blocksign is both a protocol and a web service for legally signing any document, contract, or agreement. The protocol describes the steps anyone can take to sign or verify a document through the Bitcoin blockchain. In a world populated by programmers, that’s all we would need. In the realm of reality it’s difficult to imagine widespread usage without an easy to access implementation. And that’s why we created blocksignit.com .

We will now describe the protocol in human-terms, albeit we assume some level of familiarity with bitcoin. If you would rather like to read the technical details, head for the specification. Either way, we are very eager to discuss. Please reach out to us, we would love to hear your comments or suggestions.

The concept of signing already exists in bitcoin. You have to sign your transactions before the network accepts them. That’s why no one else but you can spend your money. So we could try to put a document into the “memo line” of the transaction. Then by signing the transaction, you would be signing the document. But there is one little problem. It would make the transaction huge. The network would refuse to incorporate it into a block, no matter how much transaction fee we might be willing to fork over. And what if we would like to sign something without disclosing all the details to the whole world?

Lucky for us there is a simple solution. If we take the hash of the document, and write that on the memo line, that makes the transaction size manageable. It also lets you sign and verify that a document has been signed while also keeping your secrets safe from 3rd parties.

So this is it. You hash the document, every signing party publishes a bitcoin transaction with the hash in it, and the document is BlockSigned!

There are several benefits of using the blockchain for this purpose. The most prominent of them all is that proof of signature is not controlled by any single entity. Members of the bitcoin network instead act as witnesses, or public notaries, to attest your signature. BlockSign’s use of the blockchain also provides you, or anyone with access to the document, with the ability to easily verify the authenticity of a signature. And that’s really why we sign things, isn’t it?

We're BlockSign, a service for legally signing any document, contract or agreement. We launch today with the belief that BlockSign will change the way people sign documents, make commitments and enter into contracts digitally. 

We believe BlockSign can be a breakthrough because it is built on a technology called "the blockchain" -- the same framework that powers the digital currency, Bitcoin. We believe the blockchain is uniquely capable of creating the type of trust necessary to empower digital signatures to achieve their full potential.

Practically, the blockchain allows us to make one key guarantee, the BlockSign guarantee:

You will always have easy, free access to private records of what you've signed using BlockSign.

That is what differentiates BlockSign not only from pen and paper but also from existing e-signature services. It is core to how we achieve our vision of building a signature service that is simple, cost effective and trustworthy.

We look forward to using this space to expand on what we're doing technologically, the people we're interacting with and servicing, and any other key updates.