Re: [Ntp] Splitting the Roughtime draft?

[Marcus Dansarie <[e-mail]>]

On 2021-01-31 01:51, Watson Ladd wrote:
> Dear WG,
> 
> Right now we have interop on the wire format of version -03. What we
> don't have is a serialization format for reports of malfeasance.
> 
> In order to move forward I'm considering reducing the draft to just
> the wire format for the protocol leaving the malfeasance serialization
> to a subsequent draft. This would let us start a WGLC on the parts
> that aren't going to change, and potentially accelerate deployment of
> servers and clients.

I think it's important to at least define a basic serialization schema
for both malfeasance reports and lists of servers. If we don't, we risk
ending up with several incompatible formats for data exchange in the
Roughtime ecosystem.

A de facto standard for server lists already exists (ecosystem.json) and
only needs to be documented in the draft. A simple malfeasance report
format in the same spirit as the server list format could be a JSON
object with an ordered list of objects, each containing a nonce and a
server response, both in base64 format. Verifying the report would be as
simple as (1) verifying that the list is a valid list of chained
Roughtime responses and (2) applying the same validity tests as clients.

Tal Mizrahi and others raised a number of issues with how the security
model is described in the draft. [1] I don't think they where ever
addressed. We should probably be proactive in fixing this in the draft,
as it is something that the IESG will have opinions about. In
particular, I think we need to be very clear about the fact that all
trust in Roughtime is rooted in the long-term keys and that they are
expected to be valid for a very long time indeed.

After fixing these two two points, I would be happy to support a WGLC.

> I'd appreciate feedback on this plan. In particular I think some of
> the question of timing algorithm will be explicitly out of scope:
> Roughtime is intended for secure time checks and ensuring *rough*
> synchronization.

Fully agree.

Kind regards,
Marcus



[1] https://mailarchive.ietf.org/arch/msg/ntp/wsm0sjAagWfr8FBxje_5mZL07A4/
https://mailarchive.ietf.org/arch/msg/ntp/JLNNAkI-eD_Nmoi8P5rr-BYRVUU/
https://mailarchive.ietf.org/arch/msg/ntp/uADaxiNDQT8BQi5pyVwd_rcFw8Y/
https://mailarchive.ietf.org/arch/msg/ntp/4OyvMuxHQnOcwmvFBa1099us3P4/