Better Baby Book – Privacy Policy

Last updated: September 2026

Summary: Better Baby Book stores all your data locally on your device by default. Optional family sync uses AES-256 end-to-end encryption (zero-knowledge). No tracking, no ads, no third-party SDKs.

1. Data controller

The controller for data processing in connection with the App Better Baby Book is:
Cyril Wendl · bbb@cblum.ch · https://cblum.ch

2. Local data storage by default

All information you enter in the App—including names, birth dates, milestones, growth measurements, feeding and diaper logs, quotes, nicknames, voice memos and photos—is stored exclusively on your Apple device by default. It does not leave your device unless you explicitly enable family synchronisation.

3. Optional family sync (end-to-end encrypted)

When you enable family synchronisation, Better Baby Book follows a strict zero-knowledge design:

On-device encryption: All profiles, milestones, logs and media are encrypted on your iPhone with AES-GCM-256 before transmission.
Local key derivation: The 256-bit cryptographic key is derived locally from your family passphrase using HKDF-SHA256. Your passphrase is never sent to the server.
Zero-knowledge server: The server (hosted in Germany by Hetzner Online GmbH) stores only encrypted ciphertext. Neither the operator nor any third party can read your content or access your key.
Roles & permissions: Group owners can manage settings and invite or remove members. All members can synchronise and edit child profiles.

4. Sync account

Family sync requires a basic account (username, e-mail address and a cryptographically hashed password). These credentials are used solely for authentication and group membership.

5. In-App feedback

Via the “Feedback & Ideas” form you may voluntarily send messages, suggestions or bug reports to bbb@cblum.ch. You may optionally include diagnostic data (app version, OS version, device type). This information is used solely to process your feedback and is never used for marketing or advertising.

6. No third-party tracking or advertising

We do not sell, rent or share your data with advertising networks, data brokers or analytics providers. The App contains no third-party tracking SDKs and displays no advertising.

7. Device permissions

Photo library: Used only with your explicit permission to add photos to milestones, nicknames or the gallery.
Microphone: Used only with your explicit permission to record voice memos for nicknames. Audio stays local or is synced end-to-end encrypted.
File system / import & export: Used to create backups (PDF photo books, ZIP archives) or import existing archives.

8. Medical disclaimer

Health-related content in Better Baby Book—including growth charts, milestones, feeding guidance, vaccination and nutrition information—is provided for general informational purposes only. It does not constitute medical advice and does not replace diagnosis, treatment or advice from a paediatrician, midwife or other qualified healthcare professional. You remain responsible for decisions concerning your child. If in doubt, consult a qualified professional; in an emergency contact local emergency services immediately.

9. Data deletion & logout

You can reset all local data at any time via App Settings → Reset Data. Signing out of a sync account removes all synced child data from the device. Deleting a child profile or account also removes the corresponding encrypted records from the server.

10. Your rights & contact

Under Swiss data protection law (DSG) and the GDPR (where applicable) you have the right to access, correct or delete your personal data at any time free of charge. Contact us at bbb@cblum.ch.