apt authentication?

[Sebastian Tennant <sebyte@smolny.plus.com>]

Hi all,

Just tried to install a package to solve a problem I'm having with my
DHCP lease when apt told me something I've never heard it say before:

  delboy:~$ apt-get install dhcpdump
  Reading package lists... Done
  Building dependency tree... Done
  The following extra packages will be installed:
    libpcap0.8 tcpdump
  The following NEW packages will be installed:
    dhcpdump libpcap0.8 tcpdump
  0 upgraded, 3 newly installed, 0 to remove and 1 not upgraded.
  Need to get 394kB of archives.
  After unpacking 893kB of additional disk space will be used.
  Do you want to continue [Y/n]?
  WARNING: The following packages cannot be authenticated!
    libpcap0.8 tcpdump dhcpdump
  Install these packages without verification [y/N]?
  E: Some packages could not be authenticated
  delboy:~$

Is this new and is authentication/verification soon to be applied across
the whole apt repository?  How does it work exactly?  Do any extra apt
packages need to be installed?

sebyte