Hi Heikki,

Calculating the CAK is part of downlink Macsec, meaning the Macsec between 
supplicant and authenticator (switch-host). However an important part of Macsec 
within a Cisco infrastructure is uplink Macsec, meaning the authentication 
server authenticating the authenticators. It's an integral part of dot1x-based 
Macsec which ensures that the traffic is not just encrypted and authenticated 
end to end, but also that the infrastructure is trusted end to end prior to 
downlink Macsec.

The term Cisco uses for authenticating infrastructure is NDAC (Network Device 
Admission Control) and coupled with downlink Macsec allows the authentication 
and encryption of the entire network (assuming there is supporting hardware and 
the topology allows it). 

This is explained as of page 54 in the link I provided. It is well illustrated 
in page 61. Cisco use EAP-Fast for NDAC. The secure seeding device closest to 
the authentication server (this is configurable) authenticates the neighboring 
switches, which in turn authenticate their neighboring switches, and so on. 
When the equipment is authenticated, it can perform Macsec for the endpoints. 
This is a great way to minimizing the attack surface for MITM, replay attacks, 
packet sniffing and so on across your entire networking infrastructure and not 
just the access layer.

Is there any chance that Radiator supports uplink Macsec within a Cisco 
infrastructure? I'm aware that they tailored their solution to Cisco ISE and 
therefore this may not be a solution based on standards, but it would be 
interesting to know whether this can be supported without ISE.

________________________________________
From: radiator-boun...@open.com.au [radiator-boun...@open.com.au] on behalf of 
Heikki Vatiainen [h...@open.com.au]
Sent: Sunday, April 17, 2016 2:54 AM
To: radiator@open.com.au
Subject: Re: [RADIATOR] A few questions regarding MacSec

On 16.04.2016 00:27, Nadav Hod wrote:

> Does Radiator support Macsec for switch-host and switch-switch links?
> The two connection types are quite different. There is a great
> explanation of how Macsec works and what information is exchanged
> here:
>
> https://clnv.s3.amazonaws.com/2015/usa/pdf/BRKCRS-2892.pdf
>
> As you can see, there is more than just the Eap-key-name avpair being
> returned and calculated. However that's what Radiator documentation
> specified as supported.

If you are thinking about the CAK (Connectivity Association Key), it
will be returned with MS-MPPE-Send-Key and MS-MPPE-Recv-Key quite
similar to what TLS based EAP methods too. This is how Radiator already
works: you will have EAP-Key-Name and the MS-MPPE-* attributes in
Access-Accept. The doc you referred to seems to say CAK is returned, but
not how.

See for example Cisco's MacSec deplyment guide and section '2.2.2 IEEE
802.1X and Master Key Distribution'

http://www.cisco.com/c/en/us/products/collateral/ios-nx-os-software/identity-based-networking-services/deploy_guide_c17-663760.pdf

Thanks,
Heikki

--
Heikki Vatiainen
h...@open.com.au
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