Return-Path: X-Original-To: tls@ietfa.amsl.com Delivered-To: tls@ietfa.amsl.com Received: from localhost (ietfa.amsl.com [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 046DC1A045E for ; Mon, 11 Aug 2014 10:27:04 -0700 (PDT) X-Virus-Scanned: amavisd-new at amsl.com X-Spam-Flag: NO X-Spam-Score: -1.977 X-Spam-Level: X-Spam-Status: No, score=-1.977 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, FM_FORGED_GMAIL=0.622, HTML_MESSAGE=0.001, RCVD_IN_DNSWL_LOW=-0.7] autolearn=ham Received: from mail.ietf.org ([4.31.198.44]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id dwqMQnZnI3_7 for ; Mon, 11 Aug 2014 10:27:02 -0700 (PDT) Received: from mail-wg0-f47.google.com (mail-wg0-f47.google.com [74.125.82.47]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id 9E4971A0037 for ; Mon, 11 Aug 2014 10:27:02 -0700 (PDT) Received: by mail-wg0-f47.google.com with SMTP id b13so8653355wgh.6 for ; Mon, 11 Aug 2014 10:27:01 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to:cc:content-type; bh=vsfDBdv3lN3NkOMznYJUzpdF+8nXBGGccNl1p0UCLHA=; b=Sy1YOo6m2c8YkkPyoiMDJSZSvLjUhzr1QIZzlDKE98pQt7k2ArNsaAVclPAqBEzx5A vK+89Tyk47eoZ0W+xtkefCXiMEh7yraQM8hfcANHktJPZgyd0TVJB0sz4/jNHyxFpjk9 QxYsABMK1m0dapMVeB6WTRR+s5oH0cO5+/GzCbppXQFG0N7n3JakoHHZW7vknVTFi3t5 uvIEgApu0iSeqZ7mCRny9p7cWMztw1o0Snz6Y0uGIoRRVeAzrSvod9YgukYfHSETAxat IMNcpn682Fn3ft8895gZXH69zFzlJRh4zN3u4jdc000jOUTs4Te/Sdzm1RiZ4fQlOol+ CW0g== X-Gm-Message-State: ALoCoQnlcQSCbIKn5Z/gP4A1UyoJILq641nxGEck06abiJLK7s0rN1418yUUesZDtHJPujnbqWcn X-Received: by 10.180.186.3 with SMTP id fg3mr20754458wic.78.1407778021024; Mon, 11 Aug 2014 10:27:01 -0700 (PDT) MIME-Version: 1.0 Received: by 10.217.128.12 with HTTP; Mon, 11 Aug 2014 10:26:20 -0700 (PDT) X-Originating-IP: [2620:101:80fc:232:6049:62d9:3779:ea46] In-Reply-To: References: From: Eric Rescorla Date: Mon, 11 Aug 2014 10:26:20 -0700 Message-ID: To: Watson Ladd Content-Type: multipart/alternative; boundary=001a11c26aceddbe1105005ddc75 Archived-At: http://mailarchive.ietf.org/arch/msg/tls/hsEvAGJ3cS-Z2J2A2T6oBOqjHT4 Cc: "tls@ietf.org" Subject: Re: [TLS] "Draft Version" extension X-BeenThere: tls@ietf.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: "This is the mailing list for the Transport Layer Security working group of the IETF." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 11 Aug 2014 17:27:04 -0000 --001a11c26aceddbe1105005ddc75 Content-Type: text/plain; charset=UTF-8 On Mon, Aug 11, 2014 at 10:15 AM, Watson Ladd wrote: > > On Aug 11, 2014 9:55 AM, "Eric Rescorla" wrote: > > > > Experience with HTTP 2 has shown that it's convenient to be able to > > distinguish which draft version you're implementing so you don't end > > worrying about interop between various I-D versions. Accordingly, > > for TLS 1.3 I'd like to define a temporary extension that indicates which > > TLS 1.3 draft it implements. The idea here is that the client would > signal > > TLS 1.3 and then "draft 3" and the server would only negotiate 1.3 if > > it had a compatible draft. Otherwise it would fall back to TLS 1.2. > > How would the server negotiate v2 vs v3? > You negotiate TLS 1.2 versus TLS 1.3 via the usual mechanism, I.e., the version in the ClientHello. -Ekr --001a11c26aceddbe1105005ddc75 Content-Type: text/html; charset=UTF-8



On Mon, Aug 11, 2014 at 10:15 AM, Watson Ladd <watsonbladd@gmail.com> wrote:


On Aug 11, 2014 9:55 AM, "Eric Rescorla" <ekr@rtfm.com> wrote:
>
> Experience with HTTP 2 has shown that it's convenient to be able to
> distinguish which draft version you're implementing so you don't end
> worrying about interop between various I-D versions. Accordingly,
> for TLS 1.3 I'd like to define a temporary extension that indicates which
> TLS 1.3 draft it implements. The idea here is that the client would signal
> TLS 1.3 and then "draft 3" and the server would only negotiate 1.3 if
> it had a compatible draft. Otherwise it would fall back to TLS 1.2.

How would the server negotiate v2 vs v3?


You negotiate TLS 1.2 versus TLS 1.3 via the usual mechanism, I.e., the version
in the ClientHello.

-Ekr

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