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Legal · Privacy

Privacy Policy

Effective 19 August 2026 Last updated 19 August 2026 Version 1.0

This policy is written in plain language and in good faith for a pre-release product. It describes how Mes is designed to handle data. Where a practice depends on infrastructure still being finalised, we say so. In case of any discrepancy between language versions, the Ukrainian text prevails.

This Privacy Policy explains what information the Mes application and its servers process, what they are deliberately built not to process, and the choices and rights you have. Mes is an end-to-end encrypted messenger built around a zero-knowledge server: our aim is to hold as little about you as is technically possible to deliver a message.

§ 1 Who we are

The data controller for Mes is the provider of the Mes service, registered in Ukraine. The provider's full legal-entity details will be published before public launch and are available on request.

ControllerProvider of Mes (details on request)
JurisdictionUkraine

§ 2 Privacy by architecture

Most services promise privacy through policy — a pledge not to look. Mes is built so that, for the content of your communication, there is nothing to look at. Encryption keys are generated on your device and stored in the Secure Enclave. Messages, attachments and call media are encrypted end-to-end using the Signal Protocol before they leave your phone, and are only ever decrypted on the recipient's device. The server relays sealed ciphertext.

This means the strongest protection we offer does not depend on trusting us. It follows from the design.

§ 3 What we can never see

Because of end-to-end encryption and the zero-knowledge design, we do not have access to, and cannot produce:

  • the content of your messages, attachments or files;
  • your audio or video call media;
  • your encryption keys or the ability to decrypt anything;
  • your address book or contact graph — it stays on your device;
  • the membership of your groups, which is maintained cryptographically between members, not uploaded to us;
  • your IP address as seen by the person you call — calls are routed through a relay.

We cannot hand over what we do not hold. A request for the plaintext of your messages is one we are technically unable to satisfy.

§ 4 What we process, and why

To register a device and route sealed messages, a minimal amount of data is necessarily processed:

  • Registration data — a randomly generated account identifier and your device's public keys. Purpose: to establish your identity to other users and route messages. We do not require a phone number or email to use the app.
  • Routing & delivery metadata — the minimal data needed to deliver a sealed envelope to the right device (e.g. a recipient routing token, message size after padding, and delivery/acknowledgement state). We work to minimise this over time (message padding to fixed sizes, and sealed-sender techniques on the roadmap).
  • Push notification tokens — an Apple Push Notification service (APNs) token, used only to wake your device so it can fetch a waiting sealed message. Push payloads do not contain message content.
  • Call relay data — while a call is connected, a TURN relay forwards encrypted media between participants. It processes network traffic transiently and does not record media.
  • Diagnostics — if, and only if, you opt in, anonymised crash and performance diagnostics to help us fix defects. Off by default.
  • Support & waitlist correspondence — if you email us or request early access, we process the address and content you send us, to reply and to send you a TestFlight invitation.

§ 5 Legal bases

Where the EU General Data Protection Regulation (GDPR) or the Ukrainian Law “On Personal Data Protection” applies, we rely on:

  • Performance of a contract (GDPR Art. 6(1)(b)) — to provide the messaging service you asked for;
  • Legitimate interests (Art. 6(1)(f)) — to keep the service secure, prevent abuse, and deliver messages reliably, balanced against your rights;
  • Consent (Art. 6(1)(a)) — for optional diagnostics and for contacting you after a waitlist request, which you may withdraw at any time.

§ 6 This website

This marketing website is intentionally quiet. It uses no advertising trackers, no third-party analytics, and sets no non-essential cookies. If you submit the early-access form, your email application opens with a message addressed to us — nothing is transmitted to a server in the background. Our hosting provider may keep short-lived, standard server access logs (such as IP address and user-agent) for security and reliability; these are not used to profile you.

§ 7 Who we share with

We do not sell your data, and we do not share it for advertising. We rely on a small number of infrastructure providers acting as processors on our behalf:

  • Server hosting — the operator of the infrastructure that runs the relay;
  • Apple — for App Store distribution and APNs push delivery;
  • TURN relay — to carry encrypted call media.

Each processes only what is described above. If you run your own Mes server (see the Terms of Service), you become the operator of that infrastructure and responsible for it.

§ 8 Law-enforcement requests

We respond to lawful, properly served legal requests, but we can only provide data we actually hold. Given the design in §3, that excludes message content, keys, contact lists and group membership. We will not weaken encryption, insert backdoors, or add mechanisms to access plaintext. Where lawfully permitted, we aim to notify affected users of requests concerning them.

§ 9 Retention

Sealed messages are stored only until they are delivered, then deleted from the server; undelivered messages are dropped after a limited retention window. Registration data persists while your account exists. When you delete your account, associated server-side records are removed, and your local data is wiped from your device. Diagnostics and support correspondence are kept only as long as needed for their purpose.

§ 10 Your rights

Subject to applicable law, you have the right to access, rectify, erase, restrict or object to the processing of your personal data, and to data portability. You may also lodge a complaint with a supervisory authority — in Ukraine, the Ukrainian Parliament Commissioner for Human Rights (Ombudsman); in the EU/EEA, your local data-protection authority.

Please note that end-to-end encryption limits some requests in your favour: because we cannot read your messages, we also cannot export their content for you — only your device can. To exercise any right, contact us at andrey@stetsenko.org.

§ 11 Children

Mes is not directed to children under 16. We do not knowingly process the data of anyone under 16. If you believe a minor has provided us data, contact us and we will delete it.

§ 12 How we protect data

Beyond end-to-end encryption, we use hardware-backed key storage (Secure Enclave), certificate pinning and TLS 1.3 in transit, signed requests, and a fail-closed policy that refuses to send in the clear if cryptography cannot run safely. Every additional feature is checked against these invariants before it ships.

§ 13 Changes to this policy

We may update this policy as the product matures. Material changes will be reflected by a new effective date at the top and, where appropriate, announced in the app. Continued use after an update means you accept the revised policy.

§ 14 Contact

Questions about privacy, or a request to exercise your rights? Write to andrey@stetsenko.org. We read every message.

See also the Terms of Service and the Licence Agreement.