What stays in your browser, and what the server keeps.

Walking videos stay in your browser

The Gait Analysis Lab runs its models in your browser (WebAssembly and WebGL, served by this site; no third-party service). The video file is opened on your computer and is never uploaded.

Faces are found and painted over (a solid fill, not a reversible blur) before anything is kept, and facial points are dropped: the motion data starts at the shoulders.

What leaves your browser is the result: the skeleton's motion over time, one thumbnail with faces painted over, and the details you type (title, notes, recording conditions, consent).

Encrypted at rest

That motion data, the thumbnail, your notes and the pseudonymous patient records are stored encrypted, field by field, with AES-256-GCM.

The key is kept on the server, apart from the database, and the server decrypts records to show them to accounts allowed to see them. This is encryption at rest, not end-to-end encryption.

A few figures are kept in plain form so the library can list and sort recordings: processing status, video length and size, frame counts, tracking quality, cadence and speed estimates, and a small knee-angle preview.

Who can see a record

Only signed-in accounts with a role in the lab (administrator, researcher or viewer) can open it, and the server checks the role on every request.

Viewing, creating, changing, exporting and deleting records, and every refused attempt, are written to an audit log: who, what and when, with no patient details.

Retention and deletion

Administrators set how long recordings are kept. A deleted record is hidden at once and erased permanently after the purge period (30 days unless an administrator changes it).

Your account

Your username and e-mail address, your password as a salted scrypt hash (never the password itself), when you registered, confirmed your address and last signed in, your role in the lab, and whether you said you donated.

Subscriptions and donations are paid on Mercado Pago or PayPal: STRIDE LAB never sees card details. It keeps the provider's subscription id, its status, the amount and until when it is paid.

The simulator

What the controller learns is kept in your browser. With sharing on, it uploads anonymous counts of which moves worked and where moves failed on each terrain layout.

Every 2 minutes it also sends a heartbeat for the public counter: a random id for the browser and one for the tab, the simulated time and the terrain layouts. The server keeps only keyed hashes of those ids. Sharing can be turned off in ESCAPE & LEARNING.

Analytics

Google Analytics records page views and a few feature events, never usernames, e-mail addresses, recording details or pictures. Advertising storage and signals are off.

While the simulator is open, it also sends a "sim_running" event every 2 minutes. It says only whether the tab is on screen and whether the simulation is running, so an open simulator counts as active.

Visitors from Europe, or from a country that cannot be told, are asked first, and nothing is sent until they accept. The answer can be changed with Cookie settings at the bottom of the page.