Encrypted backups created on Android 4.3 cannot be restored on 4.4

Question

Problem to restoring Backup

1. Create an encrypted backup on 4.3 with adb backup (specify password)
2. Try to restore on 4.4
3. Restore silently fails.

Show me below error:

Password is considered incorrect, even though it is:

W/BackupManagerService(774): Incorrect password

W/BackupManagerService(774): Invalid restore data; aborting.

Answer 1

This is caused by recent changes to the SecretKeyFactory. If a password contains a non ASCII character, then the password set in 4.3 will not be valid in 4.4. I believe Google is already aware of the issue.

You can try to use an open source Android-Backup-Extractor to repack your backup with a new password or wait until Google fixes the issue.