Unable to restore encrypted ZIP file backups

[Terrance]

• I have searched open and closed issues for duplicates
• I am submitting a bug report for existing functionality that does not work as intended
• I have read https://github.com/signalapp/Signal-Android/wiki/Submitting-useful-bug-reports
• This isn't a feature request or a discussion topic

---

I had to fumble around a bit trying to restore the custom backups of my messages -- by default they weren't being recognised:

• I selected the Signal default backup on first run, but after confirming my number I reached the main screen with no messages
• Attempting to load the full backup showed "No encrypted backup found!"
• Attempting to load the plaintext backup showed a restoration screen for a fraction of a second, then the app reloads and no messages have been imported

I double-checked the storage location and the built-in Chat backups settings, and the paths are correct (/sdcard/Backups/Signal in this case, with FullBackups/SignalExport.zip and PlaintextBackups/SignalPlaintextBackup.zip inside).

The existing backups I had (both plaintext and full) were created with both the corresponding "store in zipfile" options enabled.

I had the backups password to hand and have successfully decrypted the backups on another device -- what I ended up doing was re-zipping the full backup without a ZIP file password, moving that in place of the existing backup at FullBackups/SignalExport.zip, and then using the Restore encrypted backup option, at which point it restored successfully.

Device info

Device: OnePlus Nord CE
Android version: 12 (OxygenOS 12.1)
Signal version: 5.40.4.0-JW (I'm aware this is old, I started with the same version used to create the backups)

Looks like the log file export only goes back 10 minutes, so I missed the useful output -- if there's interest in this then I can try it on another device and see if it's reproducible.

[johanw666]

Seems the Signal install didn't know the key of the zipfiles. That should be restored when restoring a default backup but otherwise I'm afraid this method is the only way around. I should add a password entry field if the zipfile can't be decrypted due to a missing password.