Key Distribution Center (KDC) is a central authority dealing with keys for individual computer ( nodes) in a computer network.
- It is similar to the concept of the authentication Services (AS) & Tichel Granting Service (TGS) in Kerheros.
- The basic idea is that every node shares an unique secret key with the KDC. Whenever user wants to communicate securely with user B , the following action take place.
The background is that A has a secured secret key KA with KDC . Similarly B is assumed to share a secret key KB with the KDC.
A sends a request to KDC encrypted with KA , which includes:
Identifies of A & B
A random number R , called as names.
KDC responds with a message encrypted with KA , continuing :
a. One - time symmetric key KS.
b. Original request that was sent by A, for verification
c. Plus, KS encrypted with KB & ID of A encrypted with KB.
- A & B can now communicate by using KS for encryption