Privacy Policy

1. On-device photo processing

Stardrift (星云相册) is provided by Pengtian Feng. With your permission, the app accesses photos and their existing capture-date and location metadata for on-device semantic search, similar-photo tools, Star Trails and photo presentations. Photos, queries, image feature vectors and the index are not sent to developer servers or cloud model services. No account is required. The app contains no advertising tracking or third-party behavioral analytics SDK.

2. Face data

The following distinguishes data processed or stored by the app on your device from data collected or uploaded to the developer. Local processing still involves face data; the absence of an upload does not mean face data does not exist.

2.1 Types and sources

The app includes an on-device people-grouping component that processes only photos available under your Photos permission. It does not obtain face data from the camera, TrueDepth, ARKit or Face ID. During processing, Apple Vision detects face regions, facial landmarks and capture quality in memory. Landmarks align the face and are not stored separately. Locally persisted data can include 112×112 face thumbnails, numerical feature vectors for similarity matching, quality scores, local photo identifiers, group identifiers, group-average feature vectors, names entered by the user and manual exclusion flags.

2.2 Purposes and activation

The only purposes of face data are grouping the same person within your own photo library, displaying person previews, correcting groups and finding photos by a name you supplied. It is not used to establish real-world identity, authenticate users, advertise, track, sell data, match external identity databases, or train or improve machine-learning models. In the current version 1.2.0 (17), people grouping is off by default and the release interface has no entry point to enable face scanning. Ordinary semantic search does not require it. If an earlier internal-test installation enabled it, previously generated data may remain locally and can be cleared under Section 2.4.

2.3 Storage, disclosure and sharing

Face thumbnails, features and groups are stored in a local SwiftData database inside the app sandbox on the current device. Vision and the bundled SFace/Core ML model run on device. Face data is not transmitted to the developer, model providers, advertisers, analytics services or other third parties. The app has no face-data upload, cloud inference or cross-device person-sync function. Apple device backups may include this database according to your backup settings; this is managed by Apple device backup, not an app upload to a model service. The developer cannot access your backups.

2.4 Retention, withdrawal and deletion

Temporary face regions and landmarks are used during processing and are not stored separately. Persisted face features, thumbnails, groups and names have no automatic expiry period; they remain until you clear them or delete the app. From version 1.0 (15), open Me > Privacy controls > Clear face data and confirm. This turns off people grouping, waits for any active scan to finish, then deletes all local face records, thumbnails, group features and names while keeping original photos, the ordinary photo index and Star Trails. Clearing also works on a new installation with no face records. A deletion failure displays a retry message rather than a success message. Revoking Photos permission in system Settings stops subsequent access but does not itself erase stored data. The system Delete App action removes data for the current installation; Offload App may retain it. These actions do not retroactively delete Apple device backups. Backup retention, deletion and restoration are controlled through your Apple backup settings; after restoring an old backup, you can clear face data again.

3. Permissions and your choices

You may grant full or limited Photos access and change it in system Settings. Limited access permits only the selected photos. Add-photo access is used for exports you initiate; motion information is used only for tilt interactions. The app does not obtain live location. Locations come from existing photo metadata. Sharing sends only the photos or exported content you select to your chosen system share destination, without internal face features or the people database.

4. Other local data and Apple services

The photo index, photo references, Star Trails, preferences and usage counters are stored locally. Deleting the app neither deletes originals in the system photo library nor cancels subscriptions. The system may download iCloud photos according to your settings. Apple handles purchases, subscriptions, payments and restoration, and the app uses StoreKit to check entitlements. The developer receives no payment-card information. Apple services and backups are governed by Apple’s privacy policy and your account settings.

5. Support, website and updates

If you email support, we use your email address, issue description and voluntarily supplied materials only to reply and troubleshoot, not for advertising or sale. Avoid sending unnecessary face images or private photos. Email atianspace8179@gmail.com to request deletion of support correspondence. This support website is hosted on the developer’s Tencent Cloud server in mainland China. Web requests include the IP address, requested path and basic browser request information needed to serve pages and diagnose errors. The website has no advertising, behavioral analytics or photo-upload interface. Visiting it does not read the app’s photos or people database. Legacy GitHub Pages URLs remain hosted by GitHub. Policy updates are dated on this page.