The following packages cannot be authenticated

Marius Gedminas marius at
Fri Dec 2 09:09:22 UTC 2011

On Wed, Nov 30, 2011 at 08:53:41AM -0600, sktsee wrote:
> On 11/30/2011 04:57 AM, Shawn Pringle wrote:
> [snip]
> >
> >Before installing samba, I received this warning:
> >
> >"The following packages cannot be authenticated!"  I didn't know there
> >was any kind of certificate system in place.  Can someone tell me what
> >this means exactly, how serious is the risk and why common are
> >packages that can be authenticated?
> >
> That usually means that you need to run "sudo apt-get update" before
> installing your package so that apt can authenticate the repo.

Incidentally, why does it happen?  An intermittent network connection
that didn't let the previous apt-get update download the right
Release.gpg?  An archive update that coincided with your apt-get update,
and so you downloaded a Packages.gz that is newer than your Release

> The following link explains the process of how APT authenticates
> repositories and checks package integrity.

I see my question is also raised (but not answered) in that FAQ:

} Another problem you may encounter if using testing or unstable is that
} if you have not run apt-get update lately and apt-get install a package,
} apt might complain that it cannot be authenticated (why does it do
} this?). apt-get update will fix this.

Marius Gedminas
A computer without Windows 9x is like a fish without a bicycle.
                -- With apologies to Gloria Steinem
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