Re: [TLS] Is stateless HelloRetryRequest worthwhile? (was Re: TLS 1.3 Problem?)

Michael D'Errico <mike-list@pobox.com> Sat, 03 October 2020 02:13 UTC

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From: Michael D'Errico <mike-list@pobox.com>
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Date: Fri, 2 Oct 2020 22:13:14 -0400
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Subject: Re: [TLS] Is stateless HelloRetryRequest worthwhile? (was Re: TLS 1.3 Problem?)
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On 10/2/20 14:15, I wrote:
> The server also needs to know the entire HelloRetryRequest message
> since this goes into the Transcript Hash calculation:
>
>    Transcript-Hash(ClientHello1, HelloRetryRequest, ... Mn) =
>        Hash(message_hash ||        /* Handshake type */
>             00 00 Hash.length  ||  /* Handshake message length (bytes) */
>             Hash(ClientHello1) ||  /* Hash of ClientHello1 */
>             HelloRetryRequest  || ... || Mn)

Please don't tell me all the current TLS 1.3 implementations
forgot to include the HelloRetryRequest in the transcript hash.

Mike