New in version 0.3.6
v0.3.6
New: Opt-in Debug Logging (Settings). Off by default. If you hit a
bug, turn it on, reproduce it, then Export to send us a diagnostic
log. Secrets are removed and your contacts' names become anonymous
tags like before anything leaves your phone. It auto-erases
after 24 hours, and a banner shows whenever it's recording.
When someone who sounds like your mother calls in a panic asking for bail money, Signet lets you verify it's actually her.
Each paired contact generates a rotating 4-word phrase that only the real person's phone can produce. You ask her to read her phrase aloud; you type what you hear. Green banner: verified. Red banner: something's wrong — hang up and call her back on a number you already trust.
Signet works over any channel. Voice calls, video calls, text, email, in person. The only requirement is that the two of you paired once, in person or over a trusted channel, before the crisis.
Built for a world where AI voice cloning is commodity. Defends against:
* Real-time voice and video deepfakes
* Pre-recorded deepfake voicemails
* Vishing using scraped biographical knowledge
* Compromised messaging accounts where the attacker has chat history but not the paired device
* SIM swaps
* Reflection attacks: the rotating code is direction-aware, so an attacker echoing your own phrase back at you fails
Core properties:
* No server. No cloud. No account. No INTERNET permission.
* No telemetry. No analytics. No ads.
* Hardware-backed secrets via Android Keystore, StrongBox when available.
* Offline-first; airplane mode does not affect any flow.
* RFC-validated crypto (X25519, HKDF-SHA-256, AES-256-GCM, BIP-39).
* Open source, AGPL-3.0.
v0.3 includes in-person pairing, long-distance pairing, lost-phone recovery via paper or file, multi-relationship storage, in-person rekey, bulk backup (every paired relationship in one encrypted file with a single 8-word unlock), a printable challenge-response grid for when the other side can't reach their phone, liveness prompts for video calls, and screenshot blocking on sensitive screens.
Not included: duress codes (gated on an abuse-analysis pass), account recovery (there is no account), cloud backup (out of scope forever).
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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.
Download F-Droid
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x86_64
This version requires Android 9.0 or newer.
It is built and signed by F-Droid, and guaranteed to correspond to this source tarball.
Permissions
-
view network connections
Allows the app to view information about network connections such as which networks exist and are connected.
-
take pictures and videos
This app can take pictures and record videos using the camera while the app is in use.
-
read the contents of your shared storage
Allows the app to read the contents of your shared storage.
-
record audio
This app can record audio using the microphone while the app is in use.
-
modify or delete the contents of your shared storage
Allows the app to write the contents of your shared storage.
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dev.digitalgrease.signet.DYNAMIC_RECEIVER_NOT_EXPORTED_PERMISSION
Download APK
25 MiB
PGP Signature
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Build Log
-
arm64-v8a
This version requires Android 9.0 or newer.
It is built and signed by F-Droid, and guaranteed to correspond to this source tarball.
Permissions
-
view network connections
Allows the app to view information about network connections such as which networks exist and are connected.
-
take pictures and videos
This app can take pictures and record videos using the camera while the app is in use.
-
read the contents of your shared storage
Allows the app to read the contents of your shared storage.
-
record audio
This app can record audio using the microphone while the app is in use.
-
modify or delete the contents of your shared storage
Allows the app to write the contents of your shared storage.
-
dev.digitalgrease.signet.DYNAMIC_RECEIVER_NOT_EXPORTED_PERMISSION
Download APK
23 MiB
PGP Signature
|
Build Log
-
armeabi-v7a
This version requires Android 9.0 or newer.
It is built and signed by F-Droid, and guaranteed to correspond to this source tarball.
Permissions
-
view network connections
Allows the app to view information about network connections such as which networks exist and are connected.
-
take pictures and videos
This app can take pictures and record videos using the camera while the app is in use.
-
read the contents of your shared storage
Allows the app to read the contents of your shared storage.
-
record audio
This app can record audio using the microphone while the app is in use.
-
modify or delete the contents of your shared storage
Allows the app to write the contents of your shared storage.
-
dev.digitalgrease.signet.DYNAMIC_RECEIVER_NOT_EXPORTED_PERMISSION
Download APK
20 MiB
PGP Signature
|
Build Log
New in version 0.3.5
v0.3.5
Fixed: About screen now shows the actual installed version
(previously stuck on a hardcoded "v0.2.0-alpha" string that
never got bumped through several releases).
Privacy policy updated to accurately describe the in-app
crash-report flow added in v0.3.4 — your crash data still stays
on your phone until you tap "Send".
-
x86_64
This version requires Android 9.0 or newer.
It is built and signed by F-Droid, and guaranteed to correspond to this source tarball.
Permissions
-
view network connections
Allows the app to view information about network connections such as which networks exist and are connected.
-
take pictures and videos
This app can take pictures and record videos using the camera while the app is in use.
-
read the contents of your shared storage
Allows the app to read the contents of your shared storage.
-
record audio
This app can record audio using the microphone while the app is in use.
-
modify or delete the contents of your shared storage
Allows the app to write the contents of your shared storage.
-
dev.digitalgrease.signet.DYNAMIC_RECEIVER_NOT_EXPORTED_PERMISSION
Download APK
25 MiB
PGP Signature
|
Build Log
-
arm64-v8a
This version requires Android 9.0 or newer.
It is built and signed by F-Droid, and guaranteed to correspond to this source tarball.
Permissions
-
view network connections
Allows the app to view information about network connections such as which networks exist and are connected.
-
take pictures and videos
This app can take pictures and record videos using the camera while the app is in use.
-
read the contents of your shared storage
Allows the app to read the contents of your shared storage.
-
record audio
This app can record audio using the microphone while the app is in use.
-
modify or delete the contents of your shared storage
Allows the app to write the contents of your shared storage.
-
dev.digitalgrease.signet.DYNAMIC_RECEIVER_NOT_EXPORTED_PERMISSION
Download APK
23 MiB
PGP Signature
|
Build Log
-
armeabi-v7a
This version requires Android 9.0 or newer.
It is built and signed by F-Droid, and guaranteed to correspond to this source tarball.
Permissions
-
view network connections
Allows the app to view information about network connections such as which networks exist and are connected.
-
take pictures and videos
This app can take pictures and record videos using the camera while the app is in use.
-
read the contents of your shared storage
Allows the app to read the contents of your shared storage.
-
record audio
This app can record audio using the microphone while the app is in use.
-
modify or delete the contents of your shared storage
Allows the app to write the contents of your shared storage.
-
dev.digitalgrease.signet.DYNAMIC_RECEIVER_NOT_EXPORTED_PERMISSION
Download APK
20 MiB
PGP Signature
|
Build Log
New in version 0.3.4
v0.3.4
New: in-app crash reporter. If the app crashes, the next launch
offers to file a pre-filled GitHub Issue with the stack trace.
Cryptographic material (paired secrets, verify codes, backup
payloads, contact labels) is redacted on-device before anything
leaves your phone. No in-process network — "File issue" opens
your OS browser.
Fixed: in-person pairing deadlock (#1). Both devices now wait for
both scan + show before advancing to verification.
-
x86_64
This version requires Android 9.0 or newer.
It is built and signed by F-Droid, and guaranteed to correspond to this source tarball.
Permissions
-
view network connections
Allows the app to view information about network connections such as which networks exist and are connected.
-
take pictures and videos
This app can take pictures and record videos using the camera while the app is in use.
-
read the contents of your shared storage
Allows the app to read the contents of your shared storage.
-
record audio
This app can record audio using the microphone while the app is in use.
-
modify or delete the contents of your shared storage
Allows the app to write the contents of your shared storage.
-
dev.digitalgrease.signet.DYNAMIC_RECEIVER_NOT_EXPORTED_PERMISSION
Download APK
25 MiB
PGP Signature
|
Build Log
-
arm64-v8a
This version requires Android 9.0 or newer.
It is built and signed by F-Droid, and guaranteed to correspond to this source tarball.
Permissions
-
view network connections
Allows the app to view information about network connections such as which networks exist and are connected.
-
take pictures and videos
This app can take pictures and record videos using the camera while the app is in use.
-
read the contents of your shared storage
Allows the app to read the contents of your shared storage.
-
record audio
This app can record audio using the microphone while the app is in use.
-
modify or delete the contents of your shared storage
Allows the app to write the contents of your shared storage.
-
dev.digitalgrease.signet.DYNAMIC_RECEIVER_NOT_EXPORTED_PERMISSION
Download APK
23 MiB
PGP Signature
|
Build Log
-
armeabi-v7a
This version requires Android 9.0 or newer.
It is built and signed by F-Droid, and guaranteed to correspond to this source tarball.
Permissions
-
view network connections
Allows the app to view information about network connections such as which networks exist and are connected.
-
take pictures and videos
This app can take pictures and record videos using the camera while the app is in use.
-
read the contents of your shared storage
Allows the app to read the contents of your shared storage.
-
record audio
This app can record audio using the microphone while the app is in use.
-
modify or delete the contents of your shared storage
Allows the app to write the contents of your shared storage.
-
dev.digitalgrease.signet.DYNAMIC_RECEIVER_NOT_EXPORTED_PERMISSION
Download APK
20 MiB
PGP Signature
|
Build Log
