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Re: [openpgp] time representation in OpenPGP

Jon Callas <joncallas@icloud.com> Tue, 05 July 2016 02:41 UTC

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From: Jon Callas <joncallas@icloud.com>
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Cc: IETF OpenPGP <openpgp@ietf.org>, "brian m. carlson" <sandals@crustytoothpaste.net>, Jon Callas <joncallas@icloud.com>
Subject: Re: [openpgp] time representation in OpenPGP
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>> 
>> I'd strongly recommend simply using a 64-bit (signed?) integer.  It's
>> compact, avoids time zones (which are a source of bugs), and is the
>> logical extension.

Signed only if you really want to express negative time in some way. I think that negative time to express times *before* the zero date is a great idea.

> 
> I've seen 64-bit integer measuring in quanta of 100ns in a few places,
> FWIW.  The finer granularity doesn't really eat into the usable range, for
> a couple axes of future-proofing.

Yes, that's VMS. It was a 100ns tick, with a zero-time of 17-Nov-1858 (that's the zero time of the American Ephemeris and more or less Julian Day One Million) and used negative time to express delta times rather than absolute. Even with that, it's fine into five-digit years.

	Jon

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