Re: [quicwg/base-drafts] Handshake loss recovery interacts poorly with amplification attack defense (#1764)

Martin Thomson <> Sat, 22 September 2018 16:41 UTC

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From: Martin Thomson <>
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Subject: Re: [quicwg/base-drafts] Handshake loss recovery interacts poorly with amplification attack defense (#1764)
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I had a different conception of this.  That is, the client runs the Initial timer fairly aggressively for longer.  That is, you set a timer for retransmitting Initial+ClientHello and rather than stopping that timer when you get a packet from the server, you stop it when either the handshake completes (or you receive an ACK in a Handshake packet).

The tweak being that you can send Initial with the ClientHello in it, but then switch to sending anything else when you've received proof that the server got your message (basically, any response other than Retry).

At that point, it doesn't matter what you put in the packet.  I was thinking that triggering standard retransmission logic would be bad in this case because you don't really have anything to send, it's just a matter of giving the server primed enough incoming bytes that it can send enough outgoing.

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