W3C home > Mailing lists > Public > w3c-ietf-xmldsig@w3.org > July to September 1999

RE: Brown draft feedback on time stamping and on criticality flags

From: Phillip M Hallam-Baker <pbaker@verisign.com>
Date: Fri, 30 Jul 1999 14:50:14 -0400
To: <david.solo@citicorp.com>
Cc: <w3c-ietf-xmldsig@w3.org>
Message-ID: <002801bedabc$5bfbfba0$6e07a8c0@pbaker-pc.verisign.com>

	I accept your main point about the GMT time (or UTC time or
whatever, Todd will probably have an issue) being key.

	The concept of 'local time' is not a very usefull one in
a world wide computer network - We agree here.

	There is an argument for being able to support local time
information however since it is in some cases necessary to correlate
data which is only available in local time.

	Consider the case in which it is the daytrading wizard which
is initiating the trades for me. Critical information that wizard
might require is the knowledge that the trade took place at 3pm
New York time, an hour before the market closed so that the position
could be covered before the end of the day.

	Unfortunately the '15 degrees of latitude' bit is only part
of the story. There is also the problem of daylight savings which
is a considerably larger headache since there is no agreed upon date
and in the US DST does not even apply in some parts. The cost of
reconstituting that information is substantial - a trusted source
of daylight savings info is now needed.

	The situation in the UK is particularly complex since nobody
knows what timezone the country will be in in five years time and the
dates on which summer time takes effect could be harmonized with the
rest of Europe anytime.

	Regardless, the local time information is secondary and
applications are free to treat the local time info (if present) as
they chose.


> -----Original Message-----
> From: David Solo [mailto:david.solo@citicorp.com]
> Sent: Friday, July 30, 1999 2:32 PM
> To: Phillip M Hallam-Baker
> Cc: david.solo@citicorp.com; w3c-ietf-xmldsig@w3.org
> Subject: Re: Brown draft feedback on time stamping and on criticality
> flags
> Phill,
> This doesn't make any sense to me.  If you're presented with a GMT time,
> you can always determine the corresponding time in whatever locale you
> care about (and even configure your SW to do it for you if you're
> lucky).  Thus you know the GMT offset for London, NY, or even onboard
> you yacht.  If you're saying that you find the fact that the computer on
> which I originated the signature happened to be configured for a
> timezone 5 hrs off GMT as important (or even if you knew it was
> somewhere in a time zone 5 hrs off GMT - although anywhere in either
> hemisphere), I think you're stretching.  Your examples all seem to be
> about knowing where it took place more specifically than (more or less)
> in which 15 degrees of longitude.
> Dave
> Phillip M Hallam-Baker wrote:
> >
> > > I think you and Tom (et al.) are indicating that there is a
> place for a
> > > different attribute which describes other properties of the signature.
> > > I think defining such an attribute is fine, although outside
> of the core
> > > syntax.
> >
> > Well that would not be my first choice...
> >
> > But I do think that it is intellectually defensible to insist that all
> > times be in GMT (something the server needs to know if time is going
> > to have any relevance) and that the local time zone information be
> > stated as an offset.
> >
> > IE if the contract is signed in Cambridge MA the time splodge has
> > format:  <XYZ time="Fri, 30 Jul 1999 09:07:44" local="-500">
> > If it is signed in Mountain View it has the format
> > <XYZ time="Fri, 30 Jul 1999 09:07:44" local="-800">
> >
> > And of course "local" would be optional since GMT is the only proper
> > time to use anyway. [cue music: Elgar vgariations, Nimrod, flags of
> > all nations (but mostly British) are unfurlled]
> >
> > Seriously, I find nothing quite so disorienting as Web surfing when
> > every random site feels the need to tell you the time of day in the
> > wrong context.
> >
> > What I want is to be able to buy shares on the London market, sell
> > them on the NYSE and be given the transaction times of both in local
> > time for my private island in the Caribean where I have parked
> the yatch.
> >
> > But at some later time I may need to know the precise local time
> > the trade went through because I need to reconcile the trade with
> > some paper documentation I got sent relating to the trade.
> >
> >                 Phill
Received on Friday, 30 July 1999 14:49:08 UTC

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