Evidence verifier

Has this capture been altered?

Every Snappy evidence bundle carries a SHA-256 fingerprint taken at the moment of capture. Drop the bundle below and the fingerprint is recomputed and compared, entirely in your browser.

Drop the evidence bundle here

The .zip Snappy downloaded, or the image and its .evidence.json as two separate files

🔒 Files never leave your device. This page makes no network requests and works offline.

How verification works

  1. When evidence mode is on, Snappy computes the SHA-256 hash of the final image at the moment it is saved and writes it into the .evidence.json manifest beside the image.
  2. This page recomputes the hash of the image you drop in, using your browser's built-in cryptography (crypto.subtle), and compares the two.
  3. If even one pixel was changed after capture, the hashes will not match. A match means the image is byte-for-byte identical to what Snappy saved.

The manifest also records the page URL, the exact capture time and timezone, who captured it, and whether anything was redacted, so a screenshot can stand on its own as audit evidence.