Privacy Policy

Last updated 2 August 2026

Mysterion proves where digital content came from. Doing that well means handling as little of your data as possible, and being precise about the little we do handle. This policy describes exactly that — it is not a generic template.

The browser extension

What happens when you verify something

When you right-click an image or video and choose Verify with Mysterion, the extension reads that file in your browser and recovers the embedded watermark locally, using WebAssembly running on your own machine. The file itself never leaves your device.

To find out whether that watermark corresponds to a real signing record, the extension sends the following to mysterion.io:

• a cryptographic hash of the content (BLAKE3), and
• the identifier recovered from the watermark, if one was found.

Both are one-way values. Neither can be turned back into your image or video, and neither identifies you.

What the extension stores

Your display preferences, and a short-lived record of the most recent verdict per browser tab so the badge can be redisplayed without repeating the work. This stays in your browser. It is not sent anywhere, and it is discarded when the tab closes.

Permissions, and why each one exists

• Access to any site. Signed content can appear anywhere, so the extension has to be able to act on the page you are looking at. It only reads a page after you explicitly invoke it from the right-click menu — it does not run in the background, and it does not watch your browsing.
• The current tab. To read the specific image or video you selected.
• Context menu. The right-click entry is the only way to start a verification.
• Local storage. Preferences and the per-tab verdict cache described above.
• Offscreen document. Watermark recovery needs browser APIs that are not available to a background service worker, so the analysis runs in a hidden document.

What the extension does not do: it does not collect your location, it does not record clicks, keystrokes or mouse movement, it does not read your browsing history, and it contains no analytics or telemetry of any kind. The only server it ever contacts is mysterion.io.

The desktop application

Signing and verification happen on your own machine. When you sign content, the signing record — hashes, the perceptual fingerprint, the timestamp and your creator identifier — is stored on our platform so that the content can later be verified by anyone. The content itself is never uploaded.

If you hold an account we store your email address, display name, optional organisation name, a password hash (Argon2id — we never store the password itself), and your two-factor secret. These exist to operate your account and for nothing else.

The website

Our web servers keep standard request logs, including IP addresses, which we use to operate the service and defend it against abuse. If you submit the contact form we receive what you type into it, and use it to reply to you.

Verification events are recorded in aggregate — the verdict, and a country-level location derived from the request — to produce the public activity map and our own operational statistics. These records are not linked to an identified person.

What we never do

• We do not sell your data, and we do not share it with third parties for their own purposes.
• We do not use your data for advertising or profiling.
• We do not use it to assess creditworthiness or for lending.
• We do not upload your content. Verification and signing happen on your device.

Third parties we rely on

We keep these to a minimum, and each is used for a single purpose:

• Amazon Web Services — hosting.
• Mailgun — transactional email, such as address verification and password resets.
• MTCaptcha — to distinguish humans from automated sign-ups on our forms.

How long we keep things

Signing records are retained for as long as the signed content needs to remain verifiable, which is the point of the service. Account data is kept while your account exists. Request logs and aggregate verification events are retained on a rolling basis for operations and security.

Your rights

You may ask us for a copy of the personal data we hold about you, ask us to correct it, or ask us to delete your account and its data. Write to the address below and we will act on it.

Deleting your account does not retract signatures you have already made: those records are what allow previously signed content to keep verifying, and removing them would silently break content already in circulation.

Children

Mysterion is not directed at children under 13 and we do not knowingly collect their personal data.

Changes

If we change this policy we will update the date at the top of this page. Material changes will be announced through the service.

Contact

Questions about privacy, or a request concerning your data: support@mysterion.io