title: Debian apt error: "The following signatures were invalid: NODATA 1 NODATA 2"
body: <p>I'm having some trouble with apt/aptitude. Recently, out of nowhere, I realized I couldn't install anything and <code>apt-get update</code> would produce this result:</p>
  
  <pre><code>$ sudo apt-get update
  Get:1 http://security.debian.org wheezy/updates Release.gpg [1,936 B]
  Get:2 http://ftp.debian.org wheezy Release.gpg [1,936 B]
  Get:3 http://ftp.debian.org wheezy-updates Release.gpg [1,936 B]
  Get:4 http://security.debian.org wheezy/updates Release [1,936 B]
  Ign http://security.debian.org wheezy/updates Release
  E: GPG error: http://security.debian.org wheezy/updates Release: The following signatures were invalid: NODATA 1 NODATA 2
  </code></pre>
  
  <p>This part: <code>Ign http://security.debian.org wheezy/updates Release</code> seems worrisome to me, but I don't really know what it could affect.</p>
  
  <p>I know that this is not a problem with my system. I had an old Debian VM lying around and I tested with it as well, getting the same problem. I'm getting this problem at work, if that helps, so I'm not in full control of the network here and it might be something that they did with the network.</p>
  
  <p>I also tried different mirrors, achieving the same result.</p>
  
  <p>This is my sources.list:</p>
  
  <pre><code>$ cat /etc/apt/sources.list
  deb http://ftp.debian.org/debian/ wheezy main
  deb-src http://ftp.debian.org/debian/ wheezy main
  deb http://security.debian.org/ wheezy/updates main
  deb-src http://security.debian.org/ wheezy/updates main
  deb http://ftp.debian.org/debian/ wheezy-updates main
  deb-src http://ftp.debian.org/debian/ wheezy-updates main
  </code></pre>
  
  <p>Thank you in advance.</p>