Re: (in)security of ESP with header compression

[Michael Thomas <mat@cisco.com>]

Henry Spencer writes:
 > On Wed, 16 Apr 2003, David Mcgrew wrote:
 > > >...[IPComp] the key is that there is no inter-packet state...
 > > 
 > > That makes sense.   For the record, the IPCOMP definition concerns 
 > > inter-packet state, it says that "each IP datagram is compressed and 
 > > decompressed by itself without any relation to other datagrams".
 > 
 > And in fact, a careful reading of the specification tells you that this is
 > a bit mis-stated:  compression implementations are not just permitted but
 > encouraged to keep inter-packet state, e.g. to decide whether it is worth
 > trying to compress the next packet.  It's *decompression*, and only
 > decompression, which must not keep inter-packet state.  (And that is both
 > necessary and sufficient to make IPComp robust against loss or reordering
 > of packets.)

Well, I dunno what difference it makes because ROHC is
pretty stateful on both sides...

		Mike