Solve GPG Error : “ The following signatures were invalid: BADSIG ” in Ubuntu Updates

After a long time I was updating my Ubuntu. Thankfully my daily data usage quota was remaining.

I expected everything to go as usual but the sudo apt-get update command gave me an error:

Reading package lists... Done
W: GPG error: http://extras.ubuntu.com raring Release: The following signatures were invalid: BADSIG 16126D3A3E5C1192 Ubuntu Extras Archive Automatic Signing Key <ftpmaster@ubuntu.com>
W: GPG error: http://ppa.launchpad.net raring Release: The following signatures were invalid: BADSIG B22A95F88110A93A Launchpad PPA for Bumlebee Project
W: GPG error: http://ppa.launchpad.net raring Release: The following signatures were invalid: BADSIG F1773AF13B1510FD Launchpad PPA for GNOME3 Team

To remove the bad signature error, open the terminal (Ctrl+Alt+T) and use the commands given below one by one:

sudo apt-get clean 
cd /var/lib/apt 
sudo mv lists lists.old 
sudo mkdir -p lists/partial 
sudo apt-get clean 
sudo apt-get update

After using these commands you should get rid of the errors and your Update Manager should be working fine.

Or just create a shell script with these command for future use.