Verify a timestamp

Check that a file matches its timestamp token, that the token is genuine, and that it is recorded in the public log. Your file is not uploaded.

1. The file

Drop the file, or choose Hashed on this device, never uploaded

2. The timestamp

Drop the token (.tsr) or evidence package (.zip) Read on this device

Verify independently, without trusting this website

The checks on this page run in your browser, but the code that runs them comes from this website. If the question is whether we can be trusted, you should not rely on our website to answer it.

You don't have to. A stamp is a standard RFC 3161 token, and every part of it can be checked with widely used, independent tools:

The file's fingerprint with sha256sum (Linux), shasum -a 256 (macOS) or certutil -hashfile (Windows).
The signature on the token with openssl ts -verify, against our root certificate, whose fingerprint is published in several places we can't rewrite after the fact (DNS, GitHub, the Internet Archive).
The public log: the token's entry is part of a Merkle tree whose signed checkpoints anyone can download and mirror.
Independent anchors: DigiCert and FreeTSA timestamps over our log checkpoints, and drand randomness inside them, pin the log to real time from the outside.

Read the step-by-step verification guide