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RE: Son-of-IKE Selection Criteria?


As I said in the pre-amble, you don't want your design to be constrained by
what PKIX implementations achieve. XKMS is already deployed and is in
process of being standardized.

	Phill

Phillip Hallam-Baker FBCS C.Eng.
Principal Scientist
VeriSign Inc.
pbaker@verisign.com
781 245 6996 x227


> -----Original Message-----
> From: Dilkie, Lee [mailto:Lee_Dilkie@Mitel.COM]
> Sent: Friday, December 07, 2001 2:41 PM
> To: Hallam-Baker, Phillip; 'Derek Atkins'
> Cc: 'Walker, Jesse'; ipsec@lists.tislabs.com
> Subject: RE: Son-of-IKE Selection Criteria?
> 
> 
> I see no reason to revoke a certificate just because you 
> re-issued due to a name change. There was no comprimise of 
> the original private key, so why would you need to go through 
> the expense of revoking a certificate?
> 
> Lee Dilkie
> 
> Mitel Networks
> 350 Legget Drive
> Kanata, ON, Canada
> K2K 2W7
> 
> Phone: 1-613-592-5660
> 
> "It wasn't easy to juggle a pregnant wife and a troubled 
> child, but somehow I managed to fit in eight hours of TV a day."
>      - Homer Simpson (from "The Simpsons")
> 
> 
> -----Original Message-----
> From: Hallam-Baker, Phillip [mailto:pbaker@verisign.com]
> Sent: Friday, December 07, 2001 12:13 PM
> To: 'Derek Atkins'; Hallam-Baker, Phillip
> Cc: 'Walker, Jesse'; ipsec@lists.tislabs.com
> Subject: RE: Son-of-IKE Selection Criteria?
> 
> 
> First let us be clear about the different types of dynamic address. In
> practice very few addresses are genuinely 'dynamic'.
> 
> Second, in this I will talk about 'certificates' since they 
> are what the
> group are familliar with. But remember that this is simply a 
> shorthand for
> 'binding of data to a private key' and there might be a 
> scheme such as XKMS
> supporting the use.
> 
> 1) The Address is actually static but is dynamically reallocated for
> operational reasons.
> 	E.G. most cable modem addresses which rarely change 
> (unless excite
> goes bankrupt that week).
> 
> 	Can issue a certificate bound to the IP address
> 
> 	If the IP address changes, revoke & reissue (note, 
> probably want to
> use XKMS rather than CRLs!)
> 
> 2) The Address is dynamic being allocated each time from a fixed pool.
> 	E.G. dial up access
> 
> Here we have a number of approaches,
> 
> A) Generate a key / cert for each address in the pool.
> 	When the initiator attempts to connect to the responder with the
> client credential, the request is intercepted at the POP. The 
> POP first
> performs a key agreement using the key bound to the IP 
> address, then once
> the tunnel is created forwards the client request through the tunnel.
> 
> B) Use disposable key / cert pairs.
> 	The initiator applies for a pool of key/cert pairs 
> which are cached.
> These are discarded after a single use. The disposable 
> key/cert pair may not
> even be certified by a trusted third party, it may be self signed.
> 
> C) Issue a certificate that has a wild card in it
> 	E.G. 18.23.1.* (think binary mask)
> 
> 
> While the cost of such systems may appear high the 
> concealment of identity
> is inherently an expensive process IF DONE WELL. If the 
> concealment is poor
> then better not to bother at all.
> 
> 	Phill
> 
> 
> Phillip Hallam-Baker FBCS C.Eng.
> Principal Scientist
> VeriSign Inc.
> pbaker@verisign.com
> 781 245 6996 x227
> 
> 
> > -----Original Message-----
> > From: Derek Atkins [mailto:warlord@MIT.EDU]
> > Sent: Wednesday, December 05, 2001 3:33 PM
> > To: Hallam-Baker, Phillip
> > Cc: 'Walker, Jesse'; ipsec@lists.tislabs.com
> > Subject: Re: Son-of-IKE Selection Criteria?
> > 
> > 
> > Phill,
> > 
> > "Hallam-Baker, Phillip" <pbaker@verisign.com> writes:
> > 
> > > 1. Issue every device an IP identity credential bound to 
> > its IP address.
> > > 	This is the ONLY form of identity that can provably prevent any 
> > > 	additional disclosure of identity in an IP environment 
> > since your
> > > 	IP address is known in any case.
> > > 
> > > 2. Perform two sequential key agreements, ]
> > > 	first an IP address based agreement
> > > 	second an identity based agreement encrypted under the 
> > key of (1).
> > > 
> > 
> > How would you cope with machines with dynamic IP address?
> > 
> > -derek
> > 
> > -- 
> >        Derek Atkins, SB '93 MIT EE, SM '95 MIT Media Laboratory
> >        Member, MIT Student Information Processing Board  (SIPB)
> >        URL: http://web.mit.edu/warlord/    PP-ASEL-IA     N1NWH
> >        warlord@MIT.EDU                        PGP key available
> > 
>

Phillip