Tuijo is built from the ground up so it can't read what you write to each other. Here is exactly which data we handle and which we don't.
Last updated: 13 January 2026Version: 1.0
1. Introduction
Welcome to the privacy policy of Tuijo. Tuijo is a private messaging app designed specifically for couples, with advanced end-to-end encryption (RSA-2048 + AES-256).
Your privacy is fundamental to us. This policy explains which data we collect, how we use it and what rights you have over your personal data.
🔐 Core principle
Zero-knowledge architecture: thanks to end-to-end encryption, your messages, photos and documents are readable ONLY by you and your partner. Not even we, the developers, can access your content.
2. Data we collect
2.1 Encryption system
Tuijo uses an asymmetric key-pair encryption system (RSA-2048) to guarantee maximum security and privacy:
Personal private key: generated automatically on your device and never shared with the server. It always stays on your device only, protected by the operating system (Keychain on iOS, Keystore on Android). It is required to decrypt the messages you receive.
Public key (QR code): generated together with the private key and shared with your partner via QR code during pairing. It is used by your partner to encrypt messages meant for you. It can be shared safely because it only encrypts, it cannot decrypt.
Important: we do not store any personal authentication information (email, user ID, password). The system relies solely on the cryptographic keys generated locally on your device.
2.3 Messages and content (encrypted)
Encrypted messages: message text encrypted with AES-256.
Encrypted attachments: photos, videos and documents encrypted end-to-end.
TODOs and reminders: shared reminders and notes (encrypted).
Metadata: send timestamp, message ID, message type (text/attachment/TODO).
Important note: all content (messages, attachments, TODOs) is end-to-end encrypted. We only store encrypted data that we cannot read without your private keys, which are stored ONLY on your device.
2.4 Technical data
FCM token: token for Firebase Cloud Messaging push notifications, required to send notifications when you receive new messages.
3. How we use data
3.1 Main purposes
Provide the service: sync messages between your devices and your partner's.
Notifications: send push notifications when you receive new messages or reminders.
Security: maintain the integrity and security of the pairing system.
Improvements: fix bugs and improve the app's features.
3.2 What we do NOT do with your data
We don't read your messages (impossible thanks to E2E encryption).
We don't sell your data to third parties.
We don't use your data for targeted advertising or profiling.
We don't share your content with anyone (except legal cases, see section 5).
4. Encryption and security
4.1 Encryption architecture
Tuijo uses a two-layer encryption system:
RSA-2048: for the secure exchange of public keys during pairing.
AES-256: for the encryption of messages and attachments.
Unique key per message: every message has a randomly generated, unique AES key.
🔑 Your private keys
Your RSA private keys are stored EXCLUSIVELY on your device using flutter_secure_storage, an encrypted storage system protected by the operating system (Keychain on iOS, Keystore on Android). Not even we can access them.
4.2 Security measures
HTTPS/TLS: all communications between app and server use secure, encrypted connections.
5. Data retention and deletion
Data deletion can be carried out directly from the app by either of the two partners. Both partners have full control over the shared data and can delete it at any time.
6. Contact
For privacy questions or requests, you can contact us:
Privacy is at the heart of Tuijo. We designed the app from scratch with end-to-end encryption to ensure your conversations stay private between you and your partner. We will keep protecting your privacy as a core principle.