Fresh Proof

"Hold up today's newspaper" is easy to fake. These four words aren't: they come from public randomness that didn't exist until a few seconds ago. Show them in a photo, video or message and anyone can check it wasn't made any earlier.

Check a code

How it works

• Every 30 seconds the drand network (run by universities and companies in the League of Entropy) publishes a new random number. Nobody, including us, can know it in advance.
• Your four words are the first four bytes of that number, each mapped to one of 256 words. The round number tells anyone exactly which random number to look up.
• Put the words and the round number in your photo, video or message. Anyone who opens the check link (or types the round number above) sees the same four words and the moment they first became public.
• Everything runs in your browser. We don't store anything, and there's no account.

Good for

• Selling something online: a photo of the item next to today's code shows you have it right now.
• Showing an account is really you, right now, without sending ID.
• Proving a screenshot, a setup or a room is current and not an old picture.

What it can't prove

• It proves "not made before" a moment, not "not made after". Post quickly, or pair it with a public post (or Called It) to pin down the other side.
• It doesn't prove who made the content, or that the words weren't edited into a photo afterwards. Handwriting the words on paper beside the subject makes editing harder; it doesn't make it impossible.
• It trusts drand to be honest and online. Your browser doesn't check drand's cryptographic signature itself.
• Four words is 32 bits: plenty to stop anyone guessing a future code, not a security key.