There is no public key available for the following key IDs

Problem : “There is no public key available for the following key IDs”
I have problem when I run “apt-get update” on debian5(lenny).

Solution : “There is no public key available for the following key IDs”

apt-get install debian-keyring debian-archive-keyring
apt-key update
apt-get update -y

Short link: http://taxze.com/?p=24
Canonical link: http://www.taxze.com/there-is-no-public-key-available-for-the-following-key-ids/