Return-Path: X-Original-To: tls@ietfa.amsl.com Delivered-To: tls@ietfa.amsl.com Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 4A7733A02BD for ; Fri, 24 Apr 2020 11:32:07 -0700 (PDT) X-Virus-Scanned: amavisd-new at amsl.com X-Spam-Flag: NO X-Spam-Score: -2.097 X-Spam-Level: X-Spam-Status: No, score=-2.097 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, FREEMAIL_FROM=0.001, HTML_MESSAGE=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, URIBL_BLOCKED=0.001] autolearn=ham autolearn_force=no Authentication-Results: ietfa.amsl.com (amavisd-new); dkim=pass (2048-bit key) header.d=gmail.com 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 56n6mPtT9b87 for ; Fri, 24 Apr 2020 11:32:05 -0700 (PDT) Received: from mail-io1-xd35.google.com (mail-io1-xd35.google.com [IPv6:2607:f8b0:4864:20::d35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id D8FAF3A0141 for ; Fri, 24 Apr 2020 11:32:05 -0700 (PDT) Received: by mail-io1-xd35.google.com with SMTP id w4so11371932ioc.6 for ; Fri, 24 Apr 2020 11:32:05 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=aCZRJDMt4NMfD3u9NqeMiwadWCV87SVnW4+/JDUOgNI=; b=WHfZI/KxfHaRRCadVqjjSngyKRkz8oUhaZ3ANXHzQEhNiwH0Wd7Q445NOJrXfC/5fK NYqXL9bR5KvR4685Boz7lvCmN95EmQXSl5q3K8UxWkaRwH4dLaFMEQ9TZCqY2Tp9WGFO SFnTfM2froaz3B1BFd42uaow7CKQc6ZW+t58Tdl09+pJPthiLeYq1DFVvjNcetFvTsMk nRDuV0/WAtOaGcJKBO/lxNvaGjBHtfhakRFKbdJdvi7kX+3BzueowSDBeK7aeDcjbpTH M7X1k6Sex/DvnG0x7yrMM6wdiH5B68joMdRhMmCRNftmwi0JDZIVYVzCFCaq7eMqvBPI ebdA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=aCZRJDMt4NMfD3u9NqeMiwadWCV87SVnW4+/JDUOgNI=; b=jvANSvVhUsyHrB0wQoQ5b6Ra3cfijoFYbaPRg9mPwp5JtA7/c5zrz5LAtvi5Hm2e4j hGbERSMSO03c/VPG2AIWIxRRIM1cfFlt8/vjMLarFlz2otSiBqkz9yUvE5L8DZv+Ppk6 bTdOxcG2Yt8PllKoqDZ/wlbr7xUhwh55fFjAcm7eZ2OrOo+qreviUDl9EexY4io2dUBi 9K5HSSacC1NTYxPQReibM1/eQW8GoQ++TYvieZZa1b5xUCHtKDgdMTo+ECKtxfuHm4z3 8RRcEBODoenzciuIBj6s2QBbyqirkWPOj1AiFGPtx4u+gtv1EsVnYo/JSECgxSoVrSpv d8Tw== X-Gm-Message-State: AGi0PuZnSlQJmgf9z8cJV9/M3ISAPi99F5S5kTeO84WsOfB6330s7Ib6 4SXpI6X69bU//WpoUnfB4U5XauIzCPYGmLsVEZigd/5b X-Google-Smtp-Source: APiQypJ21vuNHwQiT+ym3RasgsAo05xvZO+xWqPwen3PKoab8mnWMCiDxtQ4eLPLRxEAzQRbWeSCk+LuO4v4O6SHiK8= X-Received: by 2002:a02:cd01:: with SMTP id g1mr9815893jaq.131.1587753124985; Fri, 24 Apr 2020 11:32:04 -0700 (PDT) MIME-Version: 1.0 References: <786abd25-5fc7-46f4-90c4-511a648d0450@www.fastmail.com> In-Reply-To: <786abd25-5fc7-46f4-90c4-511a648d0450@www.fastmail.com> From: Rob Sayre Date: Fri, 24 Apr 2020 11:31:47 -0700 Message-ID: To: Christopher Wood Cc: "TLS@ietf.org" Content-Type: multipart/alternative; boundary="000000000000017ee605a40d9599" Archived-At: Subject: Re: [TLS] ECHO padding review and some open issues X-BeenThere: tls@ietf.org X-Mailman-Version: 2.1.29 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: Fri, 24 Apr 2020 18:32:07 -0000 --000000000000017ee605a40d9599 Content-Type: text/plain; charset="UTF-8" On Thu, Apr 23, 2020 at 4:31 PM Christopher Wood wrote: > > Is this PR ready to go? If not, why not? What would you change, and why? > (Concrete suggestions are highly encouraged!) Note also that this is > currently only a recommended padding algorithm. Implementations are > therefore free to do what they wish. Is this acceptable? Do we need to be > more prescriptive? Food for thought! > It took me a while to notice that many of the padding debates aren't so important if ECHO allows arbitrary structs/extensions in the encrypted ClientHello. The recommendation is fine as a minimum, as long as servers are tolerant of unknown extensions in the ciphertext. thanks, Rob --000000000000017ee605a40d9599 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
On Thu, Apr 23, 2020 at 4:31 PM Christoph= er Wood <caw@heapingbits.net&= gt; wrote:

Is this PR ready to go? If not, why not? What would you change, and why? (C= oncrete suggestions are highly encouraged!) Note also that this is currentl= y only a recommended padding algorithm. Implementations are therefore free = to do what they wish. Is this acceptable? Do we need to be more prescriptiv= e? Food for thought!

It took me a while= to notice that many of the padding debates aren't so important if ECHO= allows arbitrary structs/extensions in the encrypted ClientHello. The reco= mmendation is fine as a minimum, as long as servers are tolerant of unknown= extensions in the ciphertext.

thanks,
R= ob

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