After upgrading to Ubuntu Zesty 17.04 I'd like to install a cool wallpaper but that apt-get installation fails with following

W: GPG error: http://ppa.launchpad.net/realtime.sunlight.wallpaper/rsw/ubuntu quantal Release: The following signatures were invalid: 471A70A2000BD747ED3E0F6C15A8576D6E46FCAD
W: The repository 'http://ppa.launchpad.net/realtime.sunlight.wallpaper/rsw/ubuntu quantal Release' is not signed.
N: Data from such a repository can't be authenticated and is therefore potentially dangerous to use.
N: See apt-secure(8) manpage for repository creation and user configuration details.

How can I sign this manually and have apt-get always ignore that warning?

Thanks for any clues!

  • 3
    One option would be to bypass the apt authentication and just download the .deb file directly from ppa.launchpad.net/realtime.sunlight.wallpaper/rsw/ubuntu/pool/… and then install it with dpkg -i or gdebi. – Nick Weinberg May 8 '17 at 22:45
  • 1
    'Super-old', 'unsigned', and 'ppa' are all warning flags. The software (wallpaper or whatever) is unsupported and has not been tested by any of us for safety, function, or security. Fair warning: You're swimming far from shore in deep water. – user535733 May 8 '17 at 23:09

If it's just one or two package files (which may be the case if you're trying to install wallpapers) then I suggest just downloading the deb files from the respective PPA and install them using

sudo dpkg -i <deb-file-name.deb>


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