Privacy Policy
Effective date: 10 October 2026 Provider: Sherzod Maxmudov Contact: support@elchi.tech · https://elchi.tech
1. General provisions
1.1. This Privacy Policy (the "Policy") describes how data is handled when using the Elchi mobile and desktop application (the "App").
1.2. The App is designed so that the Provider is technically unable to access users' correspondence and personal data. This is a property of the App's architecture, not merely a promise.
1.3. Using the App constitutes acknowledgment of and consent to this Policy.
2. Accounts and identification
2.1. The App has no user accounts. No registration, phone number, email address, name, or any other personal data is required or requested.
2.2. The user's identifier in the App is a cryptographic key pair (Ed25519) generated directly on the user's device. The private key never leaves the device and is never known to the Provider.
3. End-to-end encryption
3.1. All messages, files, voice and video messages, and call-setup signals are encrypted on the user's device with the Double Ratchet protocol (vodozemac implementation) before transmission. Only the recipient's device can decrypt them.
3.2. Calls use WebRTC; the media stream is encrypted between the two devices.
4. How messages travel
4.1. Direct delivery (primary). When both parties are online, messages travel directly between devices over an encrypted QUIC connection — no server sees the message at all.
4.2. Store-and-forward delivery (fallback). When the recipient is offline, the encrypted message is deposited in a mailbox on the Provider's relay server. The relay stores only an opaque, sealed data block addressed to a recipient key: it cannot read the content and cannot identify the sender (sealed-sender technology). The block is deleted upon delivery; undelivered blocks are destroyed automatically after a set period.
4.3. Link previews. When the user sends a message containing a web link, the App fetches that page from the sender's device to build a small preview (title, description, thumbnail) — the same direct request a browser would make when opening the link. No Elchi server is involved and the Provider learns nothing. The preview travels inside the encrypted message, so the recipient's device never contacts the website. Tapping a link opens it in the app that owns it or in the system's in-app browser view; the App itself does not read or process web pages.
5. What the servers process
5.1. The Provider operates only its own infrastructure; no third-party messaging servers are involved.
5.2. The relay server handles encrypted blocks in transit and temporarily holds undelivered sealed blocks as described in Section 4.2. IP addresses inherent to any internet connection are processed transiently and only for the duration of the connection. No connection logs, IP logs, or communication-metadata records are kept.
5.3. The 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 and are deleted automatically.
5.4. The App contains and uses no analytics, crash reporting, advertising identifiers, trackers, or ads.
5.5. Accordingly, the Provider does not form personal-data databases and does not collect, store, transfer, or disclose such data to third parties.
6. Data stored on the device
6.1. Message history, contacts (public keys plus names assigned by the user), media, and settings are stored only on the user's device, encrypted at rest (SQLCipher; the encryption key is derived from the user's identity and is not stored anywhere).
6.2. The Provider holds no copy. If both the device and the recovery phrase are lost, the data is unrecoverable — a deliberate security property of the App.
7. Permissions requested by the App
7.1. Camera — video calls, scanning contact QR codes, capturing photos to send. Microphone — calls and voice messages. Photos/media — attaching and saving files. Notifications — new messages and incoming calls. Location — only when the user chooses to share their location in a chat; never accessed otherwise.
7.2. Each permission is used solely for the corresponding feature and can be denied in system settings (the feature becomes unavailable). The App never accesses the device's phone contact book.
8. Deletion
8.1. Deleting a chat or fully erasing the App (Settings → erase) irreversibly removes data from the user's device.
8.2. Relay copies of undelivered messages expire automatically. Because no user profile or account data exists on any server, there is nothing to delete on request.
9. Minors
9.1. The App is not directed at persons under 13, or under the higher minimum age where the laws of the user's country or territory of residence prescribe one.
10. Legal basis
10.1. This Policy is drawn up with regard to the following laws of the Republic of Uzbekistan: the Law "On Personal Data" (2 July 2019, O'RQ-547); the Law "On Informatization" (11 December 2003, 560-II); the Law "On Telecommunications" (new edition, 27 December 2024, O'RQ-1015).
10.2. By architecture, the Provider does not process personal data; all processing occurs on the user's own device under the user's own control.
11. Changes
11.1. If the App's data practices change, this Policy will be updated with a new effective date. Material changes will be announced in the App or at https://elchi.tech.
12. Contact
Questions: support@elchi.tech · https://elchi.tech