Last updated: November 1, 2026
Developer: Radioactive Coding LLC, an Iowa limited liability company, United States.
Contact: privacy@radioactivecoding.com
This policy covers the Cipherwind app for Android and the Cipherwind open page on this website. (The app was called Sendlock while it was being built.)
1. The short version
Cipherwind locks files and messages on your device. The files and messages you lock or open, the passphrases you type or generate, and your keys are handled on your phone. We do not have an account system, we do not run a server that receives your files, messages or passphrases, and we cannot read them. The app is free and shows ads from Google; the only things that leave your phone are what you choose to send, and what Google’s services (ads, purchases, nearby sending and the code scanner) handle, as described below.
2. What stays on your device
- Files and messages. Locking and opening happen on your phone. The app does not upload what you lock or open. The locked file or message goes only where you send it.
- Passphrases. A passphrase is used to lock or open and is not stored. If you copy one, the app clears it from the clipboard after about a minute while the app is open, and the next time you open the app. The app reads the clipboard only when you tap Paste or use the Lock clipboard tile or shortcut.
- Your key and contacts. If you make a key pair, the private half is stored on your phone, encrypted with a key held by Android’s secure Keystore. Contacts (names and public keys) and your settings (theme, whether to remove hidden details first, a “tip seen” flag) are stored on your phone only. If you back your key up, you choose where it goes: a printed sheet, a QR code or text you copy.
- Temporary copies. A photo or voice note you take inside the app stays in the app’s private storage until it is locked, and is then deleted. A file received from a nearby phone, and the unlocked copy of a file you open, are kept in the app’s private storage only while you need them and are removed when you leave the screen or the app starts again. Nothing is put in your gallery unless you choose to save it.
- Removing hidden details. The app reads the details in a photo or Office file (location, camera, author) on your phone to remove them, and tells you what it removed. Those details are never sent anywhere.
- Hand-offs. “Send the passphrase by text message” and “Remind me to delete it in 7 days” open your messaging or calendar app with the text ready. Cipherwind cannot read your messages or your calendar, and nothing is sent or saved until you do it in that app. Printing a key backup sheet uses your phone’s own print system.
3. When data leaves your device
- Only when you ask. You can share a locked file, save it, show a message as a QR code, or send a file to a nearby phone. After you send a locked file or message, what the other person does with it is up to them.
- Send to a nearby phone. This uses Google’s Nearby Connections, part of Google Play services, over Bluetooth and Wi-Fi. The file goes directly between the two phones, not through our servers, and the app shows a code on both phones to compare first. The other phone sees your phone’s name. Google Play services may process technical information to make the connection work, under Google’s privacy policy.
- Scanning a QR code. The app uses Google’s code scanner, part of Google Play services. It shows its own camera screen, so the app itself does not need the camera permission. Scanning happens on your phone. Google may collect usage or diagnostic information about the scanner under its privacy policy.
- Take a photo. The app asks your phone’s camera app to take the picture and save it only inside Cipherwind. Your camera app has its own settings and policy.
- The open page. On the open page, a locked file or message is opened in your browser. The page makes no network requests while you use it, so what you open is not uploaded. Loading the page is an ordinary web request to our website, so our web host receives the usual information any website does, such as your IP address and browser type. See our website privacy page.
4. Ads and purchases (Google)
- The free version shows one small banner ad from Google AdMob. AdMob may collect and use your device’s advertising ID, approximate location derived from your IP address, how you interact with ads, and diagnostic information, to show and measure ads and to prevent fraud, under Google’s privacy policy. We do not receive this information. Paid users never start the ad service.
- In the European Economic Area, the United Kingdom and Switzerland, a consent form from Google asks for your choice before ads are requested. You can change it later in Settings, Ad privacy options. You can also reset or delete your advertising ID in your phone’s settings.
- If you buy a subscription (ad-free, or Pro, which includes ad-free), purchases, billing, renewals and refunds are handled by Google Play. Whether you have one is checked with Google Play on your phone. We do not run an account system and we do not receive your payment details.
5. Permissions
- Internet: for ads and the subscription. The app does not send your files, messages or passphrases over the internet.
- Bluetooth, Wi-Fi and Nearby devices: only to find and connect to another phone for a nearby transfer. We do not use them to find where you are, and we do not collect or store your location. (On Android 12 and older, Android itself ties this to the location permission.)
- Microphone: only when you tap Record a voice note. Nothing is recorded in the background, and the recording stays inside the app until it is locked.
- Advertising ID: used by the ad service in the free version, as described in section 4.
- Files you pick: the app opens only the files you choose, through Android’s file picker. It does not have access to your other files.
6. Security
Locked files and messages use the open age format (passphrase files use scrypt with ChaCha20-Poly1305; key files use X25519). How strong a passphrase lock is depends on the passphrase: use the generator, and send it by a different route than the file. No system is perfectly secure, and we cannot recover a passphrase or a file for you. The app is designed to be reviewed: other tools can open what it makes. Read the Terms for the limits.
7. Your choices and rights
Because we do not hold your files, messages, keys or an account about you, there is nothing for us to export or delete. You can delete everything the app keeps by clearing its data or uninstalling it. Depending on where you live (for example the European Economic Area, the United Kingdom, Switzerland, or some US states), you may have rights over personal data that Google or we hold about you, such as access, correction, deletion and objection. For data Google processes, use Google’s own tools; for anything we hold (only emails you send us), email privacy@radioactivecoding.com.
8. Europe, the UK and Switzerland (GDPR)
Who is responsible. Radioactive Coding LLC, an Iowa limited liability company in the United States (privacy@radioactivecoding.com), is the developer of Cipherwind. Because we do not receive or store your files, messages, keys or any account data, we generally act only as the provider of software that works on your device.
What we process. What you lock, open or send is processed only on your device, under your control. We do not run servers that receive it, and we do not use analytics or tracking tools of our own. The data processed by Google services (ads, purchases, nearby sending, the code scanner) is described in sections 3 and 4.
Legal bases. For ads: your consent, requested through Google’s consent form before any ad is requested; you may withdraw it at any time in Settings, Ad privacy options. For purchases: performance of the contract with you, handled by Google Play. For emails you send us: our legitimate interest in answering you.
Your rights. You have the right to access, correct, erase, restrict or object to the processing of your personal data, to data portability, and to withdraw consent at any time without affecting earlier processing. For data we hold (only emails you send us), email privacy@radioactivecoding.com.
International transfers. Cipherwind itself transfers nothing to us. Google may process ad and payment data outside your country under its own safeguards. Emails you send us are processed in the United States.
Complaints. You can complain to your local data protection authority, for example the authority in your EU member state, the UK Information Commissioner’s Office, or the Swiss Federal Data Protection and Information Commissioner.
Automated decisions. We make no decisions about you by automated means.
9. Children
Cipherwind is not designed for children under 13 (or the minimum age in your country), and we do not knowingly collect data from them.
10. Changes to this policy
If we change this policy we will update the date above and, for significant changes, tell you in the app or in the store listing.
11. Contact
Questions about privacy: privacy@radioactivecoding.com.