Subject: RE: Time-stamp server. TimePrecision info

From: "Sweigert, David" <[email-masked]>
Date: Tue, 21 Dec 1999 09:29:54 -0500

Does anyone have knowledge of a commercial time-stamping service, or is 
anyone willing to suggest another alternative to obtaining time other than 
using the underlying O/S as described below.

Dave

-----Original Message-----
From: [email-masked] [mailto:[email-masked]]On Behalf
Of Todd S. Glassey
Sent: Wednesday, March 31, 1999 1:45 PM
To: Paul Koning
Cc: [email-masked]
Subject: Re: Time-stamp server. TimePrecision info

Hey Paul -
Does this mean that we are going to use NTP for timestamping? (This is not
such a bad idea and Michael McNeil and i suggested just this with the two
drafts on PKI extended NTP we did with Dave Mills),

The real issue is how timestamps are derived from a local timebase and that
the local timebase has to deal with Leap Seconds somehow... The current
Entrust protocol toolkit assumes that the time data it is handed by the
underlying OS is "legally sufficient" to use as core for timestamping-  but
the problem here is that NO COMMERCIAL OS's know about Leap Seconds and so
using the TOD clock is a gamble... that the BCP addresses these and that the
timebase services are managed out of band.

BTW, as a simple example of how most people just believe this has already
been handled, there is a paragraph in the TimeServe addition to the NT
resource kit (timeserve.txt file) that states the accuracy of the NT clock
is at best .45S/day. That in and of itself is an issue since the PC and
Server manufacturers are all worried about the bottom line so they use the
most "cost effective" (from their $$$ viewpoint) clock chips and the like.

My personal feeling is that without some BCP that has one dialing into the
ACTS servers at NIST on a once daily or twice daily model, we have know idea
what time it really is.

There are no secure NTP servers out there yet but we are woking on this and,
well - Stay tuned for the first one's announcement in the next 45 days.

Todd

-----Original Message-----
From: Paul Koning <[email-masked]>
To: [email-masked] <[email-masked]>
Cc: [email-masked] <[email-masked]>
Date: Wednesday, March 31, 1999 10:03 AM
Subject: Re: Time-stamp server. TimePrecision info

>>>>>> "Todd" == Todd S Glassey <[email-masked]> writes:
>
> Todd> How will you deal with leap seconds?  T.
>
>The NTP RFC (RFC 1305) has an excellent discussion on this and the
>approaches it describes would be good to use.  In particular, it
>suggests using a two part date/time coding (day separate from
>time-in-day).  That way the existence of leap seconds merely increases
>the range of the second field by one.  (Analogy: if you sent the
>timestamp as yyyymmddhhmmss.ssss the impact is merely that ss can be
>from 0 to 60, not 0 to 59.)
>
> paul
>