The beacon
—drand round · League of Entropy · every 3 s
connecting…
Watch time close around a file.
Nothing on this page is staged. The number on the left is a public randomness beacon that ticks every three seconds and cannot be predicted. Drop a file and its fingerprint — never the file — goes to three timestamp authorities. When they answer, the bracket closes: the file cannot be older than the round below it, and it existed by the tokens above it.
Your file
Drop a file
or tap to choose · hashed here · never uploaded · up to 8 MB
The authorities
- FreeTSAfree · volunteer—
- DigiCertfree—
- Microsec zrt.eIDAS-qualified · Budapest—
The two free legs answer anyone. The qualified third is what a plan pays for — sign in and it joins.
The bracket
not before · —
not after · —
—the whole window in which this file's fingerprint could have been made
What you just watched
The beacon is drand, run by the League of Entropy — a dozen independent operators who jointly produce a random value every three seconds that none of them can predict or backdate. A stamp records the round it saw, so the sealed bytes cannot have existed in that form before that round.
The fingerprint is a SHA-256 of your file, computed in this browser. It is the only thing that leaves: three timestamp authorities each sign it with the time they saw it, and those signed tokens are the upper edge. Two of them are free public services; the third, Microsec zrt., is an eIDAS-qualified trust service on the EU trusted list, whose token EU law presumes accurate (Regulation 910/2014, Art. 41).
Change one byte and the fingerprint changes, so the stamp no longer describes the file — and a checker says so, offline, without asking anyone. That is the whole product: stamp and check files, run a due-diligence desk, or see the plans. This page uses this browser's free daily allowance of stamps, which is why it may stop closing brackets after a dozen.