On Tue, Mar 29, 2016 at 6:25 PM, Martin Thomson <[email protected]>
wrote:

> On 30 March 2016 at 11:30, Colm MacCárthaigh <[email protected]> wrote:
> > * How is the elapsed time on the wire authenticated? can't an attacker
> > modify it and replay?
>
> It is authenticated by virtue of being part of the session transcript.
> It will be authenticated by the Finished message included by the
> client, by the key derivation, and ultimately by the remainder of the
> 1RTT handshake.
>

But isn't that too late? If you have to wait for the client finished
message before you can even decrypt the 0RTT section; what's the benefit?
it's not "0RTT" any more.

>
> > * Should the difference really be 1RTT, or 1/2 RTT (well, really "TT" I
> > guess) ?
>
> No.  The server records the time that it generates the ticket.  Then
> that ticket travels to the client (1/2 RTT).  At that point the
> counter starts.  Then, on resumption, the client stops the clock and
> sends the message to the server (1/2 RTT).
>

Makes sense!


-- 
Colm
_______________________________________________
TLS mailing list
[email protected]
https://www.ietf.org/mailman/listinfo/tls

Reply via email to