Ubuntu Extras keyring error [duplicate]

Recently I got lots of GPG errors and tried the following methods at various stages:

  1. sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 3E5C1192 
    
  2. sudo apt-get install -reinstall ubuntu-extras-keyring 
    

    (For Ubuntu Extras only)

  3. gpg –keyserver keyserver.ubuntu.com –recv 3E5C1192
    gpg –export –armor 3E5C1192 | sudo apt-key add -
    sudo apt-get update
    
  4. sudo aptitude -o Acquire::http::No-Cache=True -o Acquire::BrokenProxy=true update`  
    
  5. sudo -i   
    apt-get clean
    cd /var/lib/apt 
    mv lists lists.old
    mkdir -p lists/partial  
    apt-get clean 
    apt-get update 
    

I again got BADSIG error for extras.ubuntu.com today. So, I'm really at a loss what's causing this error to occur time and again. I really want to solve this problem once and for all.


You can automatically import all missing GPG keys using:

sudo add-apt-repository ppa:nilarimogard/webupd8
sudo apt-get update
sudo apt-get install launchpad-getkeys
sudo launchpad-getkeys