Cyfr Privacy Policy

What We Collect

Account information — username and email address, used for login and password recovery
Contact connections — who you have connected with (accepted chat requests)
Conversation metadata — timestamps and unread counts (no message content)
Device tokens — for delivering push notifications

What We Do NOT Collect

Message content — messages are end-to-end encrypted; our server never sees plaintext
Message history — encrypted messages are deleted from our server after delivery confirmation
Browsing or behavioral data
Location data
Contact lists from your phone
Any data used for advertising or profiling

End-to-End Encryption

                All messages are encrypted using the Signal Protocol with post-quantum Kyber cryptography
Encryption keys are generated and stored exclusively on your device
The server acts as an ephemeral relay — it temporarily holds encrypted messages until delivered, then deletes them
We cannot decrypt your messages. No one can, except the intended recipient.

            

Ephemeral Message Relay

                Messages are held on the server only until your device confirms receipt (ACK)
After confirmation, messages are permanently deleted from our servers
Undelivered messages expire and are deleted after 30 days
There is no server-side message archive

            

Local Storage

Your message history is stored in an encrypted database (SQLCipher) on your device
The encryption key for local storage never leaves your device
Uninstalling the app permanently deletes your local message history

Data Sharing

We do not sell, rent, or share your data with third parties
We do not serve advertisements
We do not use analytics or tracking services
We may disclose account information if required by law, but we cannot provide message content (we don't have it)

Data Retention

Account data — retained while your account is active
Encrypted messages — deleted from server within seconds of delivery
Undelivered messages — deleted after 30 days
Push notification tokens — retained while your account is active

Security

Signal Protocol (Double Ratchet, X25519, AES-256, HMAC-SHA256)
Post-quantum key encapsulation (Kyber / ML-KEM)
TLS for all network transport
Encrypted local storage (SQLCipher with AES-256)
Secure credential storage (iOS Keychain)

Your Rights

Delete your account at any time
Your message history is stored only on your device — you control it completely
We cannot recover deleted messages (we never had the plaintext)

Contact

For privacy questions or data requests, contact us at:

support@cyfrchat.com

Cloud City, LLC