First round of my stupid questions about NTS

[Hal Murray]

> I want to put arrows on the flow diagram.

Data flows both way over most connections.  You probably want the arrow to 
mean who initiates the connection rather than which way data flows.

The NTP-server to NTS-KE-server is complicated.  Gary has proposed no 
connection, start with the shared key in a file and keep the keys in sync by 
running the same update on both ends.  I think that could be made to work, but 
I'd prefer a connection.

A connection handles the case of multiple NTP servers for a single NTS-KE 
server and sets things up for the case of multiple NTS-KE servers for the same 
name.

With a connection, we could avoid storing the master keys on disk.  Clients 
would have to rekey if the system rebooted.  We could restart NTP-server or 
NTS-KE-server as long as the other end stayed up and we arranged to send the 
keys in both directions.

There is another problem area: who makes the initial certificates.  If the 
NTS-KE server makes them, then the admin has to keep the NTS-KE server and NTP 
server in sync.  If the NTS-KE server gets them from the NTP-server, then we 
need a working connection from NTS-KE server to NTP-server in order for a 
NTP-client to get started.

I think the common case of both on the same system should be OK.  If the 
NTS-KE-server can't connect to the NTP-server the NTP-client probably can't 
either.  I haven't thought much about more complicated configurations.


> Delta will need an IANA public port assignment.

The NTP port is assigned and unused for TCP.  I've been assuming that we will 
use that until somebody says otherwise.


> I'm leaning towards an organization in which the NTS client code lives inside
> ntpd; this would reduce deployment friction slightly.  Is there any scenario
> in which we'd want to run these pieces on different hosts? 

Seems reasonable.  It might be nice to have them as separate programs until we 
get things going.  For example, we could write hack debugging programs to act 
as fake NTP or NTS-KE clients to figure out what the other end is doing and/or 
poke particular cases.



-- 
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