Prove that file
existed today

Bitstamped is great for:

  • Proof of existence
  • Helping to establish prior rights*
  • Deterring plagiarism of documents
  • Proof of condition - timestamp photographic evidence

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What is it, and what is it for? is a timestamping service.

We create a publicly verifiable timestamp that you can add to printed documents using a QR code.

Download this example PDF, then scan the QR code to see verification

Record photographic evidence of something today and timestamp it so no-one can say it was post-edited.

Or use it to show you came up with an idea first - unless of course you didn't.

We don't know if it'll stand up in court, but for informal mediation of disputes, this might be useful. (No guarantees from us though, please see legal considerations)

You can choose whether to share your Bitstamped file publicly, now, later, or never.

See some screenshots on the Ink Factory blog (that's us)

Embed this cartoon on your own site

What does it cost?

$9.99 with 90 days FREE file hosting

We're in beta (a work in progress) - it will be possible to extend file hosting period before expiry.

How does it work?

Using encryption, we calculate a unique signature or fingerprint for your file.

We store that signature with the current date in a public ledger called the blockchain.

The blockchain is distributed across the internet and maintained by thousands of computers, so transactions can't be deleted or backdated.

We will generate a QR code graphic which links to a verification page - you insert the graphic into the footer of your document, and when printouts are circulated it will serve as a deterrent against plagiarism.

You can choose to make your file available for download at the verfication URL, or not.

As long as you retain the original file, you will always be able generate the signature to prove that it existed when you Bitstamped it.

Modifying your file will change the signature, and it will not match the Bitstamped signature.

We store the SHA256 digest (checksum) of the uploaded file prefixed with some marker bytes on the Bitcoin Blockchain.

We use the OP_RETURN sig proving Satoshi used in transaction are unspendable, the Satoshi are given to the block miner and the checksum is permanently recorded in transaction.

We host the file on Amazon S3 and provide a QR code and short URL for inclusion on documents, NDAs, etc.

The file checksum can be used to prove that the file existed at the time it was Bitstamped.

Who made this?

We are Ink Factory, a British printer supplies company. is an Ink Factory project, built using existing tools, technologies and APIs.

We didn't invent timestamping checksums on the Blockchain; our objective is to provide an easy to use interface to complete that task and provide a service for users to print a verifiable timestamp on their documents.

This is possibly the first non-currency application of the Bitcoin Blockchain packaged in a commercial way for non-technical users.

*Legal considerations:

Nothing onerous here, but we're not liable for any losses.

We do not know if a Bitstamped document would be more useful in a court case than a non-Bitstamped document. is a file timestamping service. All services are provided as-is. is in Beta, meaning it is still a work-in-progress. You should retain your own copy of any files submitted. Blockchain timestamps will remain useful forever, or for as long as the Blockchain and your original file exist.

When a document has been timestamped on the Blockchain, the timestamp and checksum are immutable, but you should not rely on as a means of legal protection or permanent file storage. is not a registry., Ink Factory, Ink Cartridges Limited, directors, employees and shareholders shall not be liable for any loss or damage as a result of your use or mis-use of the service. In any event, total liability shall not exceed the fee you have paid to use; and in case of any legal dispute you submit to the jursidiction of a court in England. Use of this service means you accept these terms. If in doubt, you should seek legal advice.