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Nightblast

Send urgent alerts to your contacts using encrypted SMS messages
New in version 1.0.6
Fixed an issue that allowed an attacker to send the same key twice and mark it as verified, even though it changed
With Nightblast, you can send urgent alerts to your contacts using encrypted SMS messages, with vibrations and optional sounds.

How it works:

When you connect with another Nightblast user, your phones exchange encryption keys. After you've exchanged keys, you can send encrypted alerts to each other.

Just select contacts in the Recipients section, choose Just vibrations or Sounds and vibrations and write your message. Then tap the send icon.

Nightblast encrypts your message and sends it to the selected recipients over SMS. When Nightblast receives the alert on the recipient's phone, it displays an alert dialog and vibrates the device.

If you selected Sounds and vibrations, Nightblast will play a loud sound using the Alarms audio channel, using whatever volume your phone is set to for alarms, and, if your phone is configured to let alarms break through do not disturb, you'll hear it even if do not disturb is enabled.

Disclaimer:

Nightblast uses SMS messages to communicate between devices. If your carrier charges for SMS messages, using Nightblast may incur additional charges or use your texting quota.

Connecting with another contact uses up to 12 SMS messages, and sending an alert can use up to 6 SMS messages.
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Versions

Although APK downloads are available below to give you the choice, you should be aware that by installing that way you will not receive update notifications and it's a less secure way to download. We recommend that you install the F-Droid client and use that.

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  • Version 1.0.6 (106) suggested Added on Oct 12, 2026

    arm64-v8a armeabi-v7a x86 x86_64

    This version requires Android 7.0 or newer.

    It is built and signed by the original developer, and guaranteed to correspond to this source tarball.

    Permissions
    • read your contacts
      Allows the app to read data about your contacts stored on your phone. Apps will also have access to the accounts on your phone that have created contacts. This may include accounts created by apps you have installed. This permission allows apps to save your contact data, and malicious apps may share contact data without your knowledge.
    • receive text messages (SMS)
      Allows the app to receive and process SMS messages. This means the app could monitor or delete messages sent to your device without showing them to you.
    • send and view SMS messages
      Allows the app to send SMS messages. This may result in unexpected charges. Malicious apps may cost you money by sending messages without your confirmation.
    • This app can appear on top of other apps
      This app can appear on top of other apps or other parts of the screen. This may interfere with normal app usage and change the way that other apps appear.
    • control vibration
      Allows the app to control the vibrator.
    • com.hazelhope.dubster.nightblast.DYNAMIC_RECEIVER_NOT_EXPORTED_PERMISSION

    Download APK 13 MiB PGP Signature | Build Log

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