Re: Proposed changes to ESP (andf a little AH too)

["Perry E. Metzger" <perry@xxxxxxxxxxxx>]

John Ioannidis writes:

> I'm all in favour of doing the encryption first and the
> authentication after, so that on receipt we can authenticate before
> we receive, but wasn't there some cryptographic argument against
> that sort of thing? Or was it decided back when we only had the RFC
> 182* transforms that in the case of cascaded transforms, we should
> encapsulate first with AH-MD5 and then with DES-ESP, and that
> carried over into the combined ESP transform?

Back when I was still involved in the drafting of these things (long
ago) I kept asking for input on the cryptographic and other desiderata
for picking one or the other. I got very little feedback. I don't
think the decisions was made consciously. The topic deserves a full
scale discussion...

Perry