通Hán Thông

Privacy Policy

Last updated October 13, 2026

This policy covers the Hán Thông app (desktop and mobile) and the website hanthong.com. In short: Hán Thông does not collect, store on any server or share your data. Vietnamese version: Chính sách quyền riêng tư.

Data in the app

  • Your library, word list, reading positions, reading corrections and settings are stored in the app's data folder on your device. There is no online account and no sync.
  • Each password profile is encrypted (SQLCipher, AES-256, with a key derived from the password by Argon2id). Passwords and recovery keys are never stored. The guest profile has no password and is not encrypted.
  • Profile names, profile colours and the time each profile was last opened are stored unencrypted on the device to show the list of profiles.
  • Text you add is analysed on the device only. The dictionaries, Sino-Vietnamese readings and fonts ship with the app.
  • Backup files (.htbackup) and word list exports are created only when you ask, in the place you choose.
  • The developer cannot access your data and cannot recover it if you lose both your password and your recovery key.

Network

  • The desktop app downloaded from hanthong.com checks for a new version each time it starts by fetching hanthong.com/download/desktop/latest.json. Like any web request, this reveals your IP address to the server; it contains no data from the app. You can turn it off in Settings.
  • Apps installed from Google Play or the App Store make no network requests of their own; the store handles updates.
  • The app has no ads, analytics, tracking or automatic crash reporting.

The website

  • hanthong.com uses no cookies, analytics or ads. The "try it" box runs entirely in your browser; the text you paste is not sent anywhere.
  • The website and installers are served through Cloudflare, which processes technical data of each request (such as the IP address) to operate and protect the service, under Cloudflare's own policy.

Permissions

The app only reads or writes files you pick in the system's open and save dialogs (importing text, backups, word list exports). It does not access contacts, location, photos or other apps' data.

Children

Hán Thông collects no personal data from anyone, including children.

Changes

When this policy changes, the date at the top changes too. Changes to network use are also listed in the release notes of the update.

Contact

Privacy questions: ducthanh1504@gmail.com.