Curtilage

Privacy policy

Phone Sentry privacy policy

How Phone Sentry handles your information.

Last updated:

Summary

  • Phone Sentry keeps what it learns about your phone (your installed apps, your firewall rules, your call and text screening log, and its usage counts) in the app's private storage on your phone. We do not receive any of it.
  • By itself, the app connects to the internet for one thing: about every 6 hours it asks our update server whether a newer version exists. Every other connection happens only after you turn on a feature, enter a server, or press a button.
  • When the firewall is on, your apps' internet traffic passes through Phone Sentry. Where that traffic goes depends on your settings: straight to the internet, or through a VPN (virtual private network) or SSH (Secure Shell) server that you set up.

What the app collects

All of this stays on your phone unless a section below says otherwise.

  • Your installed apps. The app reads the list of apps on your phone, the permissions each one has, and whether each one is turned on. It uses this list to rate apps by risk, to help you turn apps off, and to show what changed after a restart.
  • Screen time and processor use per app. This needs your permission. The app records how long each app was on screen. It never records what was on the screen.
  • Network activity, when the firewall is on. The app sees which app connected to which address and domain name, and whether the connection was allowed or blocked. It also counts data used per app. The connection list is kept in memory and shown on the Traffic screen. The per-app data totals are saved.
  • Packet capture, only if you start one. A capture holds copies of the network packets your apps send and receive for a time you choose (1 to 60 minutes). It is held in memory. If you tap "Export .pcap", it is saved as a file in the app's private storage.
  • Call and text screening. This is off until you turn it on. When a call or text arrives, the app checks the sender's number against your rules. If a rule blocks or allows the sender, the app saves the number, the time, and the action taken. These entries are deleted after 30 days. For texts, the app reads only the sender's number, never the message.
  • Your contacts, only for screening rules that need them. If you turn on "never block my contacts" or "block everyone not in my contacts," the app checks whether an incoming caller's number is in your contacts. It does not copy your contacts.
  • Personal data backup, only if you run it. If you back up your contacts, calendar, call history, or text messages, the app reads them in full, including the text of your messages. It writes them to a folder you pick.
  • Credentials you enter. These include your WireGuard and SSH keys and passwords, and the account number for a VPN service. The app encrypts them before saving them (see below).
  • In-app usage counts. The app records which screens you open and which features you use. These records stay on your phone (see "Analytics").

Where it goes

On your phone

  • Everything above is saved in the app's private storage, which other apps cannot read.
  • What is encrypted: your WireGuard keys, SSH keys, SSH passwords, and VPN account number. Before saving them, the app encrypts them with a key held in the Android Keystore. If the phone cannot encrypt one of them, the app saves it unencrypted rather than lose it.
  • What is not encrypted by the app: everything else, including your rules, your screening log, and your usage counts. These are protected only by Android's normal app storage protections.
  • Backups. The app turns off Android cloud backup and device-to-device transfer for all of its data. Moving to a new phone will not copy your Phone Sentry data. To keep your settings, use the app's own configuration backup.
  • Files you export. A personal data backup is saved unencrypted in the folder you pick. The configuration backup leaves out your keys, passwords, and account number unless you set a passphrase, and then it encrypts them with that passphrase. Treat both kinds of file as private.

Our servers

  • Update checks. About every 6 hours, while the phone is online, the app downloads a small version file from our update server. If you choose to update, the app downloads the new version from the same server. The app sends nothing extra with these requests. Like any internet request, they show our server your IP address and the standard information your phone sends with web requests. The phone's installer still asks you before anything is installed.
  • Blocklists, only if you turn them on. If you turn on a blocklist category (ads and trackers, malware, gambling, or adult content), the app downloads that list from our download server. It sends nothing about your traffic.
  • We do not receive your app list, your traffic, your call or text records, your contacts, your messages, or your usage counts.

Servers you choose

  • WireGuard, SSH, and proxy servers. If you set one up, the firewall sends your apps' allowed traffic through it. That server's operator can see the traffic the same way any VPN provider can.
  • A VPN service account. If you enter a VPN service's account number, the app sends it to that service to sign in. It then registers a key created on your phone and downloads the list of the service's servers.
  • Custom DNS (Domain Name System) server. If you enter your own DNS server address or DNS-over-HTTPS address, the app sends your apps' DNS lookups there.

Third-party services

  • DNS lookups while the firewall is on. The firewall answers lookups for blocked names itself. It passes all other lookups on to a resolver. With the default setting, they are sent unencrypted, either to the resolver your app asked for or to one of three public DNS resolvers built into the app. You can switch to an encrypted DNS-over-HTTPS resolver in the app's settings.
  • "Who owns this address?" lookups. If you tap this on an address or domain in your traffic, the app sends that one address or domain to public internet registry services. This happens only when you tap, one item at a time.
  • Connection test. If you press the connection test button, the app downloads a test file from a public speed-test service.
  • Exit address check. If you press "Check exit IP" while connected through WireGuard or SSH, the app asks a public service what address your traffic appears to come from. It sends this request through your tunnel.
  • AI advisor model, only if you download it. The on-device advisor needs a model file of about 491 MB. If you choose to download it, the app gets it from a public model-hosting website and checks that the file is exactly the expected one. You can also import the file yourself instead. The advisor runs on your phone and sends nothing to any server.

Permissions and why

  • See all installed apps
    • Why the app asks: List and rate every app on the phone
    • When: Always (granted at install)
  • Internet and network state
    • Why the app asks: Update checks, plus the network features listed above
    • When: Granted at install; used as described above
  • VPN connection (system dialog)
    • Why the app asks: Run the firewall on your phone
    • When: When you first turn on the firewall
  • Foreground service, notifications
    • Why the app asks: Keep the firewall running and show its always-on notice; tell you an update is ready
    • When: While the firewall is on; when an update is found
  • Run at startup
    • Why the app asks: Turn the firewall back on after a restart or update, if it was on before
    • When: After a restart or app update
  • Ignore battery optimization
    • Why the app asks: Ask Android not to stop the firewall to save battery
    • When: Only if you agree in the system dialog
  • Usage access
    • Why the app asks: Show screen time per app
    • When: Only after you grant it in system settings
  • Install apps
    • Why the app asks: Hand a downloaded update to the system installer
    • When: Only when you choose to update
  • Call screening role
    • Why the app asks: Screen incoming calls against your rules
    • When: Only after you give the app this role
  • Receive texts
    • Why the app asks: See the sender's number on incoming texts so the app can log texts from blocked senders
    • When: Only when text screening is on
  • Read contacts
    • Why the app asks: Contact-based screening rules; contacts backup
    • When: Only when you turn on such a rule or run a backup
  • Write contacts
    • Why the app asks: Restore contacts from a backup
    • When: Only when you restore
  • Read and write calendar
    • Why the app asks: Back up and restore calendar events
    • When: Only when you back up or restore
  • Read texts
    • Why the app asks: Back up your text messages
    • When: Only when you back up
  • Read and write call history
    • Why the app asks: Back up and restore your call history
    • When: Only when you back up or restore
  • Shizuku access
    • Why the app asks: Turn apps off and on, remove app permissions, and measure processor use per app
    • When: Only after you install Shizuku separately and approve access

Analytics

The app records which screens you open, which features you use, and a few results, such as whether an update check found an update. Each record has a random ID that changes every time the app starts. The records are saved in the app's private storage and used only inside the app, for example to show when you last ran a backup. The app does not send them to us or to anyone else. The app has no crash reporting and no advertising code.

Sharing with other Curtilage apps

Phone Sentry does not share data with other Curtilage apps. It has no connection to Private BrainTrust or any other Curtilage app.

Your choices

  • Turn features off. Call screening, text screening, blocklists, the firewall, VPN and SSH profiles, and the AI advisor can each be turned off in the app. If you remove the call screening role or the VPN connection in Android settings, Android stops the app from using them.
  • Clear records. You can clear the call and text screening log, the traffic list, and the per-app data totals from inside the app.
  • Export. You can save a configuration backup (rules, blocklists, DNS settings, and tunnel profiles), a personal data backup, and packet captures.
  • Delete everything. Uninstalling the app deletes all of its data from your phone. Files you exported to a folder you picked are not deleted by uninstalling, so delete them yourself.

Children

Phone Sentry is not made for children, and it does not knowingly collect information about children. The app has no accounts and sends us nothing about you.

Changes to this policy

If we change this policy, we will post the new version on this page and update the date at the top.

Contact

Questions about this policy: https://curtilage.zone/contact