A Chainstamp Proof is a way to show a digital file existed at a certain point in time. A timestamp. We submit transactions to the bitcoin blockchain and a part of each transaction contains data derived from files submitted on our website. This blockchain data then provides an unalterable anchor point in time, and because the blockchain can never be changed, the proof exits forever and is easy to verify.

The process of verifiying a Chainstamp proof includes 1) an original file 2) our website or a "proof file" that you've downloaded from us and 3) the bitcoin blockchain (which can be viewed on various websites or can be downloaded to your own system).

We use the bitcoin blockchain. Currently this is the most secure blockchain and it is verified in real time by hundreds of thousands of machines all over the world. In the future, we hope to give our users options to utilize multiple blockchains as well.

With any digital file (photos, documents, recordings, anything on your computer) you can create a timestamp for it (aka a "Chainstamp Proof"). You can drag/drop it into our Create page and the digital fingerprint of your file will be submitted as part of a transaction on the bitcoin network, creating a verifyble timestamp for your files.

Definitely get in touch with us to discuss specific integrations. We have also launched a public API for any business to build into their systems. Essentially any time your business process creates or changes a digital file is an opportunity to create a Chainstamp proof for it.

A proof file can be downloaded once a chainstamp proof is in a submitted or confirmed state. It let's you prove the existance of your original files using the blockchain and can be used even if our service is no longer around.

Warning this is pretty technical

Verify with a Proof File
• Get the sha256 hash of one of your original files that was submitted for a Chainstamp proof
• Now get the sha256 hash of your proof file
• Verify that the hash of your original file appears as text inside your proof file (open with a text editor and search for it)
• Now verify that the hash of your proof file (also known as your Chainstamp ID) appears in the Bitcoin blockchain. You can use a tool like this one to search for the proof file hash, or if you have your transaction ID from an email we sent you can use that with any Block explorer to lookup the transaction itself and search for the proof file hash inside the transaction (it is in the "OP_RETURN" section of the transaction).
• Check to make sure the transaction which contains your Chainstamp ID (proof file hash) is confirmed in a block and locate the timestamp of the Block containing this transaction.

Summary:

Your original file is hashed and that hash is put into the proof file. The proof file is hashed and put into the bitcoin blockchain as part of a transaction that gets put inside a block. Finding the timestamp of the block that contains the transaction (which contains your proof file hash) proves the existence of your original file (whose hash is inside the proof file) and provides a verifable timestamp.

The above steps are technical and are meant only to be used when our service is not available or if you want independent verification.

The Chainstamp Id is the data that was put into a bitcoin transaction as what is called an "op_return" value. It can be seen using a block explorer if you view your transaction there (find your transaction Id from email or from verify page.). The Chainstamp ID is a "hash" (sha256 hash) of your proof file. If the hash of one of your original files (that was submitted on the create page) exists inside your proof file, and your Chainstamp ID is in the blockchain, then you now have a Chainstamp Proof or a blockchain verifiable timestamp of your data.