[LBo] Mint Linux

[Troy]

Thanks to everyone who replied to my Mint Linux question.  After reading the
Mint Linux forum, I found that the packages in the Mint Linux repository are
not signed.  Another post stated, "As long as you only install from synapics
and apt-get you should be ok.  This is a bit like when Windows complains
that a driver is not "signed by Micro$oft"

Now that I have the answer about why the "not authenticated" message
appears, it leads to another question: what is signing a repository mean?

Thanks,

Troy