My Lucid (10.04) installation recently started warning me that the updated packages were unauthenticated. For instance, if I open Update Manager and click the "Install Updates" button, it warns me that You are about to install software that can't be authenticated! Doing this could allow a malicious individual to damage or take control of your system.
I don't remember seeing this before. I guess it looks like I don't have the right keys to verify signatures.
Update with more information:
I get the warning for all packages, including apt and linux-image.
This is what's in my /etc/apt/sources.list
(sans comments)
deb http://us.archive.ubuntu.com/ubuntu/ lucid main restricted
deb-src http://us.archive.ubuntu.com/ubuntu/ lucid main restricted
deb http://us.archive.ubuntu.com/ubuntu/ lucid-updates main restricted
deb-src http://us.archive.ubuntu.com/ubuntu/ lucid-updates main restricted
deb http://us.archive.ubuntu.com/ubuntu/ lucid universe
deb-src http://us.archive.ubuntu.com/ubuntu/ lucid universe
deb http://us.archive.ubuntu.com/ubuntu/ lucid-updates universe
deb-src http://us.archive.ubuntu.com/ubuntu/ lucid-updates universe
deb http://us.archive.ubuntu.com/ubuntu/ lucid multiverse
deb-src http://us.archive.ubuntu.com/ubuntu/ lucid multiverse
deb http://us.archive.ubuntu.com/ubuntu/ lucid-updates multiverse
deb-src http://us.archive.ubuntu.com/ubuntu/ lucid-updates multiverse
deb http://us.archive.ubuntu.com/ubuntu/ lucid-security main restricted
deb-src http://us.archive.ubuntu.com/ubuntu/ lucid-security main restricted
deb http://us.archive.ubuntu.com/ubuntu/ lucid-security universe
deb-src http://us.archive.ubuntu.com/ubuntu/ lucid-security universe
deb http://us.archive.ubuntu.com/ubuntu/ lucid-security multiverse
deb-src http://us.archive.ubuntu.com/ubuntu/ lucid-security multiverse
update 2:
Whatever it was that was wrong, it is no longer wrong, so I won't be able to verify any suggested solutions.
sudo apt-key list
show? It should include the Ubuntu Archive Automatic Signing Key (437D05B5). Also try doingapt-get update
again (a.k.a. “Check” in Update Manager) in case this was a transient error on a the mirror.