Please report privately through GitHub security advisories: go to the Security tab of this repository and choose Report a vulnerability. Please do not open a public issue or discussion for a security problem, and do not include photos of real people in a report.

Halo is a prototype maintained by one person. Reports are read as soon as possible, but there is no guaranteed response time.

Anything that could break Halo's promises:

• Faces, photos, face fingerprints, names or notes leaving the phone, or reaching the optional Worker.
• Any request to another origin, or a way around the Content-Security-Policy.
• The vault (IndexedDB, AES-GCM) readable without the key, or "Delete everything" and "Wipe now" leaving data behind.
• Consent links or helper cards carrying more than text, or being forgeable in a way that adds a person without their yes.
• Flaws in the optional Enhanced mode Worker (worker/): origin checks, session signing, schema and size caps, rate limits, logging of content.
• Secrets committed to the repository.

• Wrong or missed matches. Halo is a hint, not proof, and says so; report these with the "Wrong match report" template (no photos).
• The app lock being a lock screen rather than extra encryption. The app says this.
• Findings that need a rooted device, a malicious browser extension or physical access to an unlocked phone.
• Known limits of the archived face library (@vladmandic/face-api) unless they cause a privacy problem.

See also the threat model.