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Re: [quicwg/base-drafts] Why are stateless reset tokens 16 bytes long? (#2018)

Kazuho Oku <notifications@github.com> Mon, 26 November 2018 04:00 UTC

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Subject: Re: [quicwg/base-drafts] Why are stateless reset tokens 16 bytes long? (#2018)
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Kind-of related, but by rereading #1041 I notice that a Stateless Reset is considered valid even for packets that arrive from a non-validated path (see [section 10.4.1](
https://quicwg.org/base-drafts/draft-ietf-quic-transport.html#rfc.section.10.4.1)).

Is that intentional? Or should we limit the detection of Stateless Resets to packets that arrive from a pre-validated path?

I ask this because the current design of CID allows 2<sup>18\*8</sup> of space to identify a connection (because CID is generated by the endpoint that uses it to identify the connection), whereas a stateless reset token only provides 2<sup>8\*8</sup> space (because token is generated by peer and therefore be suspected to birthday attacks.

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