Subject: [mobile-ip] Authenticating BU and PKI

From: Damien Routier <[email-masked]>
Date: Wed, 25 Apr 2001 17:52:59 +0200

Hi,

I read most of the solutions proposed for authenticating BU, it seems
that none of you wants to use a PKI for the key distribution.

I wonder why , is it a problem of scalability , computing abilities of
the MN due to public key cryptography or ...?

thanks for paying attention to this "dummy" question
have a nice day

Damien 
Motorola Research Center, Paris

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From: Pekka Nikander <[email-masked]>
Date: Mon, 30 Apr 2001 12:50:46 +0100

[Sorry for this late reply but I am way back in my mail.]

> the MN due to public key cryptography or ...?

IMHO, experience has (almost) shown that global PKIs just don't work.
Local PKIs (e.g. company wide or maybe even country wide) can be made
to work.  As far as I know, we have only one example of a reasonably
well working global PKI (the SSL certificate infrastructure), but
even that has far too many technical and trust problems.  Just to
take one, have you ever checked how many CAs do you implicitly
trust once you've installed a new version of your Web browser?
What do you think, how many users even understand what are the
security CA settings in your web browser (provided that they can
open the right configuration panel)?

In this particular case (authenticating BUs), secure reverse
DNS would be the "right" PKI for the purpose.  However, getting
it running seems like quite an obstackle, and even if we had it,
authenticating a random MN would be quite expensive in terms
of the number of needed DNS queries and signature verifications.

Just to clarify: A simple infrastructure with some global CA
providing simple certificates is not enough and/or feasible.  The 
certificate must include the home address, and the issuer of 
the certificate must be authorized to issue certificates 
concerning that particular home address, etc.  

--Pekka Nikander

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From: Jean-Michel COMBES <[email-masked]>
Date: Mon, 30 Apr 2001 15:48:39 +0200

Hi,

Pekka Nikander a écrit :

> authenticating a random MN

JMC :
I think you wanted to say 'random CN'

> would be quite expensive in terms

JMC :
A possible solution would be to use the HA.
Explanation :
When the MN receives tunneled packets from its HA, the MN should send BU to
the CN (MIPv6, section 10.3). This is the _FIRST TIME_ that the MN will send
a BU to a CN and will have to set up SA to authenticate BU. So the HA knows
when the MN will have to set up IPsec parameters ... why don't we use this
fact ? When the HA encapsulates packets to the MN, it could send MN's
certificate to the CN too, including the Home Address that the MN can use
(ie. resolving the authorization problem) with the BU.

Thanks for your comments.

JMC.

--

France Telecom R&D - DTL/SSR
Jean-Michel COMBES, Internet/Intranet Security
E-Mail : [email-masked]
Phone +33 (0)1 45 29 45 94, Fax +33 (0)1 45 29 65 19
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