Nathan, > >> I've simplified this quite a bit, but I hope this is enough to answer > >> your question without getting too confusing. ;-) > > > >Please, read the RFC 4253 and do not oversimplify the things: there is > >no challenges in establishing the initial shared secret in SSH transport > >layer. > > You are refering to the wrong RFC, we are not talking about the > transport layer here, we are talking about the connection layer, info > on this can be found in RFC 4251(SSH Protocol Architecture - section > 4.1). Pardon me, but (citing RFC4251, section 4.1) ----- The server host key is used during key exchange to verify that the client is really talking to the correct server. For this to be possible, the client must have a priori knowledge of the server's public host key. ----- And the key exchange is done in the transport layer.
Moreover, section 9.3.4 called 'Man-in-the-middle' recides in the section 9.3 called 'Transport' in the same RFC4251. Don't you think that is means something ;)) > The initial shared secret is established after you have performed the > host key checking. Host key checking is performed during the Diffie-Helmann exchange at least, see RFC4253, section 8. Am I wrong? -- Eygene
