Re: [TLS] [Last-Call] Last Call: <draft-ietf-tls-oldversions-deprecate-09.txt> (Deprecating TLSv1.0 and TLSv1.1) to Best Current Practice

Peter Gutmann <> Tue, 08 December 2020 11:35 UTC

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From: Peter Gutmann <>
To: Bill Frantz <>
CC: Eliot Lear <>, Keith Moore <>, "" <>, "" <>, "" <>, "" <>
Thread-Topic: [TLS] [Last-Call] Last Call: <draft-ietf-tls-oldversions-deprecate-09.txt> (Deprecating TLSv1.0 and TLSv1.1) to Best Current Practice
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Date: Tue, 8 Dec 2020 11:35:10 +0000
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Subject: Re: [TLS] [Last-Call] Last Call: <draft-ietf-tls-oldversions-deprecate-09.txt> (Deprecating TLSv1.0 and TLSv1.1) to Best Current Practice
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Bill Frantz <> writes:

>I would like to have a few more examples of "Can't be taken out of

Well as a bit of a generalisation anything running an RTOS is likely to be
something that can't be taken out of production, and certainly wouldn't be
taken out of production for something as minor as a security changeover.
These are devices for which availability overrides all other concerns.  To
give an actual example from earlier this year, a risk analysis for a set of
devices included a discussion of how long and under what conditions you could
keep operating a device after it had been compromised by an attacker, because
the only thing worse than a device that was co-managed by an attacker would be
a device that wasn't functioning at all.  The presence of an attacker, while
suboptimal, was still far better than not having it operational at all.

Some examples of reasons why devices can't be easily upgraded include one I
mentioned a year or two back on this list for which the upgrade cycle, which
required a site visit for each device, ran over about ten years and the next
cycle was planned to complete in 2030 (but these things always take longer
than planned, I don't think they've even started it), and for more exotic
examples, "service calls to low earth orbit are expensive", "we can only
replace the hardware when the reactors are shut down for refuelling", and
"[suggested change] is a good idea but would involve renegotiating
international treaties", which still rates as the most solid reason-we-can't-
do-it I've ever heard.