Slide 4 of 14
Notes:
Slide Notes and Questions:
- Need to use kerberos proxy tickets in this situation. This allows multiple IP addr, such as the Application’s IP addr, to be specified as
valid presenters in the ticket.
- Requires the Application to have a relationship with the KDC and User Org.
- What set of information does the authorization message (AM) contain?
- What exactly is implied by “secure channel”?
- Are there any security issues?
6. The reason why a secure channel is needed between the Application and the User Org authorization server is because the AM message is
not protected. The secure channel could be removed if AM is sent as a certificate signed with some shared secret between the Application
and the User Org authorization server. An encrypted, secure channel is needed between the User and the Application because the SKey
cannot be sent in the clear.
Tcs => Application, User, IP addr of User, ts, lifetime, Kcs
Ks => Application’s shared key with the KDC
Ac => name of User, IP addr of User, ts (New Ac must be generated per service request)
Kcs => Session key for User and Application
Tcs => User Org AAA server, User, IP addr of User, IP addr of Application, ts, lifetime, Kcs
Ks => User Org AAA server’s shared key with the KDC
Ac => name of User, IP addr of User or Application, ts (New Ac must be generated per service request)
Kcs => Session key for User and User Org AAA server
* The IP addr of the Application may be used because the authenticator is created by the Application.
