Elchi Privacy Policy

Effective date: 5 September 2026 Publisher: Sherzod Maxmudov (individual developer) Contact: support@elchi.tech App: Elchi — private peer-to-peer messenger (Android, macOS; iOS planned)

Elchi is built so that we *cannot* access your data, not merely promise not to. This policy describes what the app does with data, what our infrastructure can and cannot see, and your choices.

1. No account, no phone number

Elchi has no user accounts. You do not provide a phone number, email address, name, or any personal information to use it. Your identity is a cryptographic key pair (Ed25519) generated on your device. We never receive it: the private key never leaves your device.

2. End-to-end encryption

All messages, files, voice/video messages, and call signaling are end-to-end encrypted on your device using the Double Ratchet protocol (vodozemac implementation) before transmission. Only the intended recipient's device can decrypt them. Calls use WebRTC with media encrypted between the two devices; call setup is authenticated through the same encrypted session as messages.

3. How messages travel

• Direct (preferred): device-to-device over an encrypted QUIC connection. No server sees the message at all.
• Relay (fallback): when a recipient is offline or a direct connection is impossible, the encrypted message is deposited in a mailbox on our relay server. The relay stores only an opaque, sealed, padded blob addressed to a recipient key. It cannot read the content and does not learn the sender's identity (sealed sender). The blob is deleted when the recipient collects it, and expires if never collected.

4. What our servers process

We operate our own infrastructure (no third-party messaging servers):

• Relay server: transiently processes encrypted blobs in transit and the IP addresses inherent to any internet connection. We do not keep connection logs, IP logs, or metadata records. Nothing identifies who talks to whom or what is said.
• Address discovery server: stores short-lived, device-signed records mapping a public key to its current network addresses so peers can find each other. These records expire automatically.

We collect no analytics, crash reports, advertising identifiers, or telemetry of any kind. The app contains no trackers and no ads.

5. Data stored on your device

Your message history, contacts (as public keys plus names you assign), media, and settings are stored only on your device, encrypted at rest (SQLCipher; the key is derived from your identity and is not stored anywhere). We have no copy. If you lose your device and your backup phrase, your data is unrecoverable — by design, including by us.

6. Permissions the app requests

• Camera — video calls, scanning contact QR codes, capturing photos to send. Microphone — calls and voice messages. Photos/media — attaching and saving files. Notifications — showing new messages and incoming calls. Location — only if you choose to share your location in a chat; never accessed otherwise.

Permissions are used solely for the feature you invoke and can be denied in system settings (the related feature will be unavailable). Elchi never reads your address book.

7. Deletion

Deleting a chat or wiping the app (Settings → erase) permanently removes data from your device. Relay copies of undelivered messages expire automatically. Because we hold no account data, there is nothing for us to delete on request — there is no server-side profile.

8. Children

Elchi is not directed at children under 13 (or the minimum age required in your jurisdiction).

9. Changes

We will update this policy if the app's data practices change and note the new effective date. Material changes will be announced in the app or on the website.

10. Contact

Questions: support@elchi.tech · Website: https://elchi.tech