Re: [quicwg/base-drafts] Clarify the side-effect of frequent key updates (#2788)

Kazuho Oku <> Thu, 13 June 2019 08:24 UTC

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From: Kazuho Oku <>
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Message-ID: <quicwg/base-drafts/pull/2788/>
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Subject: Re: [quicwg/base-drafts] Clarify the side-effect of frequent key updates (#2788)
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> This PR changes the text such that a peer could effectively refuse to update to the new keys for a period of 3 PTO, thereby inducing massive packet loss on all packets encrypted with the new key phase, even in the absence of packet reordering.

I think what you are missing is "endpoint SHOULD retain old keys for a period of no more than three times the PTO" (quoting from section 6). As you can see, the current text already effectively refuses updates more frequent than every 3 PTO. Hence my argument that this is an editorial change.

I also do not see why an endpoint need to update the key as frequently as couple of PTOs. Key update exists so that endpoints can replace the keys becoming weak after being used extensively. A key that becomes weak just after couple of PTOs should never be used. Therefore, it is my view is that seeing performance degradation when updating keys too frequently (due to packets being deemed lost) is a non-issue.

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