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Re: [TLS] Server time

Erik Nygren <erik@nygren.org> Sat, 04 April 2015 19:53 UTC

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Date: Sat, 04 Apr 2015 15:53:31 -0400
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From: Erik Nygren <erik@nygren.org>
To: Dave Garrett <davemgarrett@gmail.com>
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Subject: Re: [TLS] Server time
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If we do, can we please make the extension y2038 safe?  With 17 years to go
when this launches, that will be the same age as tls 1.0 and older than
sslv3.

It does seem like a useful server hello extension, however, as long as
clients wait for a complete and authenticated handshake before using it.

      Erik

Sent from my mobile device
And now, a simple issue with a simple solution:

https://github.com/tlswg/tls13-spec/issues/64

Consensus was to drop time from the random fields. Prohibiting non-random
in ServerHello.random and adding a 4 byte uint32 ServerHello.time for TLS
1.3+ seems like a really simple solution. (note that ServerHello is already
changed by dropping compression_method)

The ability of a client to sanity check or sync its time seems like
something worth having, especially for only a 4 byte cost.


Dave

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