apt-build - Authentication warning overridden. - security issue?

[Patrick Schleizer <adrelanos@riseup.net>]

Hi,

I was running:
sudo apt-build install ccache

And the output contained a message:

WARNING: The following packages cannot be authenticated!
  ccache
Authentication warning overridden.

Is this just how apt-build works or could this be a security issue due
to installing unauthenticated packages?

Cheers,
Patrick