Cairn Privacy Policy

• Precise location — collected only while you are sharing, encrypted on your device (end-to-end), and delivered only to contacts you have paired with. We store only unreadable ciphertext.
• Device identity — a public cryptographic key and an optional display name you set. This is not linked to your real-world identity unless you choose to reveal it.
• Connections — which devices you have paired with, so the app can route encrypted updates.
• Presence — a "last active" timestamp so contacts can see whether your location is current.
• Camera — used only, on your device, to scan a pairing QR code. Images are not stored or transmitted.

• We do not sell your data.
• We do not use advertising or third-party analytics/tracking SDKs.
• We do not share your data with third parties. Your location is shared only with the contacts you pair with, end-to-end encrypted.
• We cannot read your location content at any time.

Solely to provide the app's function: letting you share your live location with the specific people you choose, and showing theirs to you. There is no secondary use.

We process the limited data above to perform the service you request (and, for location, on the basis of your consent, which you can withdraw at any time by turning off sharing or deleting your identity). You have the right to access, correct, and delete your data (see below), and to complain to your data protection authority (in the UK, the ICO).

You can delete your identity and all associated data at any time:

• In the app: menu (⋮) → Backup & restore → Danger zone → Delete this identity. This is immediate and permanent.
• By request: see cairn.cappylabs.uk/delete.

Deleting your identity removes your identity, connections, encrypted location shares, pairing requests and presence. We do not retain personal data tied to your identity after deletion. Routine server security logs (which do not contain location content) may persist up to 30 days, then are purged.

Cairn is self-hostable. If you connect the app to your own server, your data resides only on your server and CappyLabs receives nothing.

Location content is end-to-end encrypted (X25519 key agreement with ChaCha20-Poly1305). Private keys never leave your device. Traffic to the server is protected with HTTPS.

Cairn is not directed to children under 13, and we do not knowingly collect data from them.

If you sign up to test Cairn, we store your email address and whether you use Android or iPhone, so we can send you the test invite and beta updates. We don't use it for anything else or share it. Android testers also join a Google Group, which Google runs under its own privacy policy. Every beta email has a link to leave, which deletes your address straight away, and we delete all beta sign-ups when the beta ends.

We may update this policy; material changes will be reflected by the "Last updated" date above.