RE: [Fwd: I-D ACTION:draft-nordmark-shim6-esd-00.txt]

["Henderson, Thomas R" <thomas.r.henderson@boeing.com>]

> -----Original Message-----
> From: Erik Nordmark [mailto:erik.nordmark@sun.com] 
> Sent: Wednesday, March 22, 2006 9:10 AM
> To: Henderson, Thomas R
> Cc: shim6
> Subject: Re: [Fwd: I-D ACTION:draft-nordmark-shim6-esd-00.txt]
> 
> Henderson, Thomas R wrote:
> > As I briefly mentioned today, there has been some 
> complementary work in
> > the HIP RG that discusses the handling of non-routable 
> identifiers in
> > legacy applications:
> > 
> http://www.ietf.org/internet-drafts/draft-henderson-hip-applic
> ations-02.
> > txt, 
> > the main differences being the use of KHI (now ORCHIDs) in 
> HIP instead
> > of CGAs.  
> 
> Is there an orchid draft? (I'm curious what might have changed other 
> than the name.)

http://www.ietf.org/internet-drafts/draft-laganier-ipv6-khi-01.txt
(see section 9.1 for changes)

> 
> > Until recently, the HIP drafts defined a "Type 2" HIT with 
> the property
> > that the upper 64 bits contained support for two levels of 
> hierarchical
> > naming (enabling reverse resolution), with the lower bits 
> being drawn
> > from a hash of the public key, but this HIT type was 
> dropped due to lack
> > of interest last year:
> > http://www1.ietf.org/mail-archive/web/hipsec/current/msg01519.html
> > It was also felt by some that 64 bits of hash was insufficient to
> > protect the binding between HIT and public key.
> 
> I can understand the 64 bit concern for HIP, since HIP is 
> securing the 
> payload. Hence the comparison is with the strength that IKE 
> can provide.
> 
> But shim6 is only preventing redirection attacks; if one cares about 
> payload protection one would run IPsec, TLS, etc above shim6.
> For the redirection threats, 64 bits is probably plenty.

Also, there were concerns about possible collisions of long-lived
identifiers (HITs) and the birthday paradox; this is discussed in the
HIP architecture draft.

Tom