CastBlast Privacy Policy

1. The Short Version

• CastBlast has no accounts, no CHKDSK Labs servers, and no analytics or crash-reporting SDK of any kind. There is nothing for the app to phone home to.
• Audio from your microphone, your files, and other apps is mixed on your phone and sent to speakers on your local network. It is never recorded to disk and never leaves your network.
• There are no ads and no in-app purchases. You pay once on Google Play and that is the entire commercial relationship.
• The app contains no advertising SDK and does not request the Android advertising ID.

2. What We Collect

Nothing. We operate no backend for CastBlast, and the app contains no third-party analytics or crash-reporting library. No audio, no device identifier, and no usage data is transmitted to CHKDSK Labs, because there is no CHKDSK Labs system on the other end to receive it. The only things the app stores about you it stores on your own device (see Section 9).

3. Distribution and Purchase (Google Play)

CastBlast is a paid app sold through Google Play. Purchase, installation, updates, refunds, and any review you leave are handled by Google under its own terms and privacy policy. We never receive, process, or store payment card numbers or banking details. As a Play developer we can see aggregated, non-identifying statistics in Play Console — install and uninstall counts, crash and ANR clusters, device and country breakdowns, ratings and reviews. That aggregate reporting is produced by Google, not by anything in the app.

Because the app is paid outright, it contains no billing library and no subscription machinery. There is nothing to upsell you and no purchase state to track.

4. Microphone

CastBlast asks for the RECORD_AUDIO permission because broadcasting your voice is the entire point of the app. When you add the microphone to the mix, audio is captured, mixed with whatever else is playing, and streamed to the speakers you selected. It is held only in memory for as long as it takes to reach them — a couple of seconds at most — and then it is gone.

The microphone arrives muted. Nothing you say reaches a speaker until you hold or latch the talk button. No recording is ever written to storage, no speech recognition or transcription happens anywhere in the app, and no audio is uploaded. Stopping the broadcast, closing the app, or revoking the permission in Android settings all end capture immediately.

Capture continues while the app is in the background and while the screen is locked. That is deliberate — a PA system that stops when your phone locks is useless — and it is why the app runs a foreground service with a permanent, non-dismissable notification for the entire time it is live. If that notification is not showing, CastBlast is not recording.

5. Other Apps' Audio (Optional)

Turning on App audio asks Android for a media projection, which is the system permission that lets one app receive what other apps are playing. Android shows its own consent dialog every time; we cannot start this, or keep it running, without you agreeing on that system screen.

CastBlast requests audio only. It captures no screen content, takes no screenshots, and receives no video frame at any point. The captured audio is mixed into the broadcast exactly like any other source: never written to disk, never uploaded, never inspected for what it contains. The app does not and cannot see which app the audio came from.

Apps are allowed to mark their audio as not recordable, and many paid streaming services do — Spotify among them. Android hands us silence for those apps rather than an error, so CastBlast watches for a stream that stays silent and tells you that the app has blocked capture instead of leaving you staring at a dead meter.

6. Audio Files You Choose

Files are opened through Android's document picker, one at a time. CastBlast deliberately does not request READ_MEDIA_AUDIO or any broad storage permission, so it has no ability to browse your music library — it only ever receives the single file you handed it. That file is read, decoded, and played. It is not copied, moved, modified, or uploaded.

7. Your Local Network

CastBlast finds speakers by listening for the standard cast service announcement on your Wi-Fi, which is why it holds a multicast lock while it is looking. It then runs a small HTTP server on your phone so those speakers can pull the audio stream from it — cast hardware fetches audio rather than having it pushed, so there is no way to do this without a server.

That server is bound to your local network and is not exposed to the internet. It serves exactly one thing: the live audio stream, at an unguessable per-speaker address, and only while a broadcast is running. It stops when you stop. Anyone already on your Wi-Fi could reach it while it is live, which is worth knowing if you are on a network you do not trust — though on many of those networks, client isolation means the speakers cannot reach your phone either and CastBlast will not work at all.

Speaker discovery and streaming happen entirely between your phone and your speakers. No part of it is routed through us, and we have no way to learn what devices are on your network.

8. Internet Radio

If you paste a stream address, your phone connects directly to that station. The station's operator will see your IP address and whatever their server logs, exactly as they would if you opened the stream in a browser. We are not a party to that connection beyond making it, we do not proxy it, and we do not keep a list of what you played. Stations you add are stored on your device so you do not have to type the address twice.

9. Local Device Storage

CastBlast keeps your settings — duck depth, master and per-source levels, mono streaming, per-speaker delay trim, and any radio stations you saved — in a private preferences file inside the app's own storage. That is the whole of it. No audio is stored at any point, so there is no recording to find, leak, or hand over. Android backup is switched off for the app, so not even the settings file leaves the device. Uninstalling or clearing the app's data deletes it, and there is no cloud copy to restore from.

10. Network Access and Permissions

Every permission the app declares, and why:

• RECORD_AUDIO — capture your voice for the broadcast (Section 4)
• INTERNET and ACCESS_NETWORK_STATE — serve the stream to your speakers and play internet radio
• ACCESS_WIFI_STATE and CHANGE_WIFI_MULTICAST_STATE — find speakers, and work out which address to serve the stream from
• FOREGROUND_SERVICE with the MICROPHONE, MEDIA_PLAYBACK and MEDIA_PROJECTION types — keep the broadcast alive with the screen off. The projection type is only claimed while app audio capture is actually running.
• WAKE_LOCK — stop the phone sleeping mid-broadcast and cutting the audio
• POST_NOTIFICATIONS — show the broadcast controls while the app is in the background

There is no location permission, no camera, no contacts, no storage permission, and no AD_ID. The app requires Wi-Fi and a microphone to be present on the device; cast speakers are not reachable over mobile data, so there is no cellular path for any of this to take.

11. Children's Privacy

CastBlast is not directed at children under 13, and we do not knowingly collect personal data from anyone, of any age. There is no advertising in the app and no data collection to configure.

12. Your Rights and Choices

• Microphone — revoke the permission in Android settings at any time; the rest of the app carries on working without it
• App audio capture — never starts without the system consent dialog, and stops the moment you turn it off or end the broadcast
• Deletion — clear the app's data or uninstall to erase every setting it holds. No audio was kept in the first place.
• Purchase data — exercise rights over your Google Play purchase record directly with Google via your Google account controls

Since we hold no personal data about you, access/correction/ portability requests to CHKDSK Labs will come back empty — but the rights described in the company-wide policy apply all the same.

13. Changes to This Policy

We may update this policy as the app or applicable law changes. The “Last updated” date above reflects the most recent revision; material changes will be noted on this page.

14. Contact