Re: [Cfrg] [TLS] Closing out tls1.3 "Limits on key usage" PRs (#765/#769)

Yoav Nir <ynir.ietf@gmail.com> Wed, 15 February 2017 17:20 UTC

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From: Yoav Nir <ynir.ietf@gmail.com>
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Date: Wed, 15 Feb 2017 19:20:39 +0200
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To: Martin Thomson <martin.thomson@gmail.com>
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Subject: Re: [Cfrg] [TLS] Closing out tls1.3 "Limits on key usage" PRs (#765/#769)
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On 15 Feb 2017, at 19:05, Martin Thomson <martin.thomson@gmail.com> wrote:
> 
> Frankly, I'm more concerned that this isn't small enough and that it
> could it be practical to deploy an implementation that don't support
> KeyUpdate.  That would cause a real interop problem.

Maybe we should resurrect [1] and add 3DES support so as to grease KeyUpdate.

No, not really, but TLS is not just the web, and there are connections that last for a long time and transfer large amounts of data. Think datacenter synchronization. At packet-sized records 24 million records amounts to 36 GB. That is considerably larger than a 4 GB software update I downloaded over HTTPS a few years ago, but not out of the ballpark.

Yoav

[1] https://tools.ietf.org/html/draft-mcgrew-aead-aes-cbc-hmac-sha2-05 <https://tools.ietf.org/html/draft-mcgrew-aead-aes-cbc-hmac-sha2-05>