Video guide

Existamp in two minutes

A writer stamps a draft chapter and a sketch: the three steps, saving the zip, and checking it later.

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Transcript

This is Existamp. In two minutes, here's how to show that your files existed on a certain day, unchanged. It's free, there's nothing to install, and you don't need an account.

Start at existamp.com, and choose what you're recording: your own work, a pitch or a prediction, any document, or photos of a rented flat, a hire car, a parcel or building work. Here, a writer stamps a draft.

Each one has its own page, with tips and ideas. Choose a stage: work in progress.

Step one: give the set a name, if you like. The name stays on your computer.

Step two: add your files. On a computer, choose them or drag them in. On a phone, you can take photos and videos in the app. Each file is fingerprinted on your device, and kept exactly as it is. Your files never leave your phone or computer.

When you're done, finish the set. Your device works out one fingerprint for the whole set: a string of letters and numbers that can't be turned back into the files. Only that is sent, to be independently timestamped.

Step three is the set's own page. The free timestamp, on the Bitcoin blockchain, usually takes a few hours, and finishes by itself. A certified timestamp, ready in seconds, is an optional extra for £2.99. You never need it to make or check a receipt.

Now save the set to your files. You get one zip: your files exactly as added, the receipt, and a guide. Keep it somewhere safe, and keep the files in it as they are.

Later, anyone can check it, with no account. Open Check a receipt, and add the zip. The checker works out every fingerprint again, in the browser, and shows that each file matches the receipt. Here the timestamp is still being finished, which is normal for the first few hours.

Remember what it shows. A receipt proves that these exact files existed, unchanged, by the time shown on the receipt. It does not prove who took the photos or made the files, or where.

That's it. Stamp your work at existamp.com.

The writer and the files are made up. The pages are as they were on the day the video was made; the site itself is always the latest.