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Re: [TLS] Data volume limits

Dave Garrett <davemgarrett@gmail.com> Tue, 15 December 2015 21:25 UTC

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From: Dave Garrett <davemgarrett@gmail.com>
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Date: Tue, 15 Dec 2015 16:25:46 -0500
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Subject: Re: [TLS] Data volume limits
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Personally, I think a hard requirement to rekey every 64GiB is reasonable enough to just use it for every cipher. I don't think cipher-specific requirements are worth the effort/complexity. Something like a MUST for AES-GCM and a SHOULD for ChaCha seems fine, though, if really desired.


Dave


On Tuesday, December 15, 2015 04:17:34 pm Watson Ladd wrote:
> I don't think that's what I intended: I think the limit should be
> ciphersuite specific. Unfortunately that requires more work.
> 
> On Tue, Dec 15, 2015 at 4:15 PM, Eric Rescorla <ekr@rtfm.com> wrote:
> > For context, see:
> > https://github.com/tlswg/tls13-spec/pull/372
> >
> > On Tue, Dec 15, 2015 at 1:14 PM, Eric Rescorla <ekr@rtfm.com> wrote:
> >>
> >> Watson kindly prepared some text that described the limits on what's safe
> >> for AES-GCM and restricting all algorithms with TLS 1.3 to that lower
> >> limit (2^{36} bytes), even though ChaCha doesn't have the same
> >> restriction.
> >>
> >> I wanted to get people's opinions on whether that's actually what we want
> >> or whether we should (as is my instinct) allow people to use ChaCha
> >> for longer periods.
> >>
> >> -Ekr

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