This just happened to me as well.
tldr; try a space character for the passphrase
Most of below may not actually be relevant, but I'm not sure what causes the problem, so here is what I did:
- I previously made a backup using the Backups GUI built in to Ubuntu (I think it's really called deja-dup), then I wiped my machine
- After the 18.04 install I configured Backups to backup the current data to a new folder
- I tried to use Backups restore feature to restore my original backup to a temp folder, but for some reason it would only restore from the new backup
- I then decided to use duplicity directly like so...
duplicity restore file://. /<my path>/temp_dir
- but it asked for a passphrase, I simply hit
Enter
, but it asked again
- I started searching for answers and found this question... I found no answers
- In a fit of desperation I tried a space character... and it worked!
It's some sort of bug I guess, my restore is still running so I'm not currently sure if any input would work or only a space.
Hope it helps