Subject: Is entity authentication necessary? On PANA Threat Analysis.

From: Pagliusi PS <[email-masked]>
Date: Tue, 19 Nov 2002 18:51:25 -0000

Dear Mohan,

according to our talk today morning on your next version of "PANA Threat
Analysis and security requirements" <draft-ietf-pana-threats-eval-01.txt>,
I am sending below the link to the article entitled: 'Is entity
authentication necessary?':

http://www.isg.rhul.ac.uk/~cjm/iean2.zip

Please see below the publication data:
____________________________________________________________________________
____________
C.J. Mitchell and P. Pagliusi. Is entity authentication necessary?. To
appear in the Proceedings of the 10th International Workshop on Security
Protocols, Cambridge, UK, April 2002. To be published in the Springer-Verlag
LNCS series.
____________________________________________________________________________
____________

All the best,

Paulo.

P.S. Alper, Basavaraj, speakers and all the audience, congratulations due to
the success of the IETF PANA WG Meeting in Atlanta yesterday (November, 18).
_________________________________________
Paulo Pagliusi
Lieutenant-Commander - Brazilian Navy Researcher
Information Security Group, Royal Holloway,
University of London.
[email-masked]
Mob. +44 (0) 7816 9355558.
_________________________________________

---

From: "Max Pritikin" <[email-masked]>
Date: Mon, 25 Nov 2002 11:36:23 -0800

On the whole a well written paper. Thanks for the pointer.

I'm not sure I agree that the solution to the DoS attack highlighted
(section 4.1) provides authentication by 'accident'. Rather it appears that
this is an inherent aspect of the solution -- that the MAC authenticates the
source of the tuple (specifically the sequence number). You do note this
interpretation (section 4.3). Possibly my disagreement is semantics?

More importantly, it should be pointed out that section 5 doesn't avoid the
authentication issue either. It depends on time T, and notes that "assuming
synchronized clocks (and the accompanying management overhead)". That
management overhead must include authentication, or the DoS attack is still
available (just un-synchronize the clocks).

It seems you argue that a "meta-session" can be established that allows the
authentication overhead to be amortized across multiple data and control
sessions but with some level of authentication is still needed. For example
using authentication to synchronize the clocks and then use time T w/o
explicit authentication during the tuple exchange. We do not dis-agree here.

	- Max

> -----Original Message-----
> From: Pagliusi PS [mailto:[email-masked]]
> Sent: Tuesday, November 19, 2002 10:51 AM
> To: [email-masked]'
> Cc: [email-masked]'
> Subject: Is entity authentication necessary? On PANA Threat Analysis.
>
>
> Dear Mohan,
>