one less onion skin

[Steve Southam]

Is it because the ORs don't know where they are in the circuit?
Of course OR3 knows it's at the end, but the others either recognize or 
relay.

Steve


James Muir wrote:
> A typical Tor circuit looks like
>
> OP -- OR1 -- OR2 -- OR3
>
> where the three "--" links are all TLS connections.  TLS protects the 
> OP's communications from adversaries outside the network, but another 
> layer of crypto (used inside TLS) is needed to protect them from the 
> onion routers themselves (e.g. we don't want OR1 to learn the identity 
> of OR3).  Thus, the onion proxy (OP) negotiates AES keys and MAC keys 
> with each onion router; call the AES keys k_1, k_2, k_3 and MAC keys 
> d_1, d_2, d_3.
>
> My question is this:  why bother with k_1 and d_1?  the communications 
> between OP and OR1 don't need to be protected from the other onion 
> routers.  I understand the reason for using k_2,d_2 and k_3,d_3, but 
> k_1,d_1 doesn't seem to be adding anything.
>
> -James
>
>