I'm new to linux and am trying to run an update, I get a lot of Hit's and Ign's but in the end I get these errors, does anybody know what they mean and how I can fix them?W: GPG error: http://speglar.simnet.is olivia Release: The following signatures were invalid: BADSIG 3EE67F3D0FF405B2 Clement Lefebvre (Linux Mint Package Repository v1) <root@linuxmint.com>W: GPG error: http://speglar.simnet.is raring Release: The following signatures were invalid: BADSIG 40976EAF437D05B5 Ubuntu Archive Automatic Signing Key <ftpmaster@ubuntu.com>W: GPG error: http://archive.canonical.com raring Release: The following signatures were invalid: BADSIG 40976EAF437D05B5 Ubuntu Archive Automatic Signing Key <ftpmaster@ubuntu.com>W: GPG error: http://ppa.launchpad.net raring Release: The following signatures were invalid: BADSIG 5A9A06AEF9CB8DB0 Launchpad PPA for Ubuntu Wine Team
Invalid signatures when running apt-get update
ubuntu;apt;gpg
As Gilles explained, most Linux repositories are signed with GPG encryption keys. apt then uses these keys to ensure the authenticity of the repositories. In order to safely use a repository, you need to add it's keys to the list that apt considers trusted. Each necessary key needs to be downloaded from a key server which is done with this command (I am using keyserver.ubuntu.com but you can use others):apt-key adv --recv-keys --keyserver keyserver.ubuntu.com KEY_NAMEFrom man apt-key:   adv       Pass advanced options to gpg. With adv --recv-key you can download       the public key.In your case, apt is complaining about keys 3EE67F3D0FF405B2,40976EAF437D05B5,40976EAF437D05B5 and 5A9A06AEF9CB8DB0, you can get all three of them by running:sudo apt-key adv --recv-keys --keyserver keyserver.ubuntu.com 3EE67F3D0FF405B2 40976EAF437D05B5 40976EAF437D05B5 5A9A06AEF9CB8DB0If all goes well you should see various lines of output including:gpg: Total number processed: 4gpg:               imported: 4  (RSA: 1)gpg:              unchanged: 0gpg:         new signatures: 4