KDC is a trusted node. KDC knows keys for all the nodes.
• KDC shares a secret key, known as a master key, with each
user and each resource that will be using Kerberos.
• KDC is comprised of Authentication Server (AS) and TicketGranting Server (TGS).
• If a new node is installed in the network, only that new node
and the KDC need to be configured with a key for that node.
• If node α wants to talk to node β, α talks to the KDC (securely,
since α and the KDC share a key), and asks for a key with which
to talk to β.