Re: [TLS] Let's remove gmt_unix_time from TLS

Nick Mathewson <> Wed, 11 September 2013 16:32 UTC

Return-Path: <>
Received: from localhost (localhost []) by (Postfix) with ESMTP id AB60F21F9FFF; Wed, 11 Sep 2013 09:32:41 -0700 (PDT)
X-Virus-Scanned: amavisd-new at
X-Spam-Flag: NO
X-Spam-Score: -1.792
X-Spam-Status: No, score=-1.792 tagged_above=-999 required=5 tests=[AWL=0.186, BAYES_00=-2.599, FM_FORGED_GMAIL=0.622, NO_RELAYS=-0.001]
Received: from ([]) by localhost ( []) (amavisd-new, port 10024) with ESMTP id tw1tpgGlb2Nm; Wed, 11 Sep 2013 09:32:41 -0700 (PDT)
Received: from ( [IPv6:2607:f8b0:400d:c02::233]) by (Postfix) with ESMTP id 0F9DF21F9BC3; Wed, 11 Sep 2013 09:32:40 -0700 (PDT)
Received: by with SMTP id ne12so5687623qeb.10 for <multiple recipients>; Wed, 11 Sep 2013 09:32:40 -0700 (PDT)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;; s=20120113; h=mime-version:sender:in-reply-to:references:date:message-id:subject :from:to:cc:content-type; bh=wirqVF+Yx86PmdTtJi1hAE+OXzeM0BKEclEh0aEKJ94=; b=FuPtkyRuJriqW1rSYlx6BNex4okopNTnml/uVhHkYi2WPL5m7yxXmXG5VsIytyUISe vtyKgFaxmueSnhvgh5Mu5K3rW2Rdk/qo7WAKNaeBp+YSK52SkYXgFqjG3Td9TBknK05M bUOKbHyg1YAyC3ByoRcAs0exCekxQEVFBSk1AmZWlsMMaEOu714bL7dxcbaLVaTyILgK ipNtAC0Rmgst5zrwZAjQZxDfgW0lWwCT5xOuoH88+i9SBI4d+DVuxdnnVZghZrNvrcLX QJLb+1bLn0EjY3249CxW2tSjlkvo0NN9Cx2LFUQtA9+WAHCf4NW2yhrOV5nsJA++MZIs J+iA==
MIME-Version: 1.0
X-Received: by with SMTP id b6mr4555274qeg.91.1378917160355; Wed, 11 Sep 2013 09:32:40 -0700 (PDT)
Received: by with HTTP; Wed, 11 Sep 2013 09:32:40 -0700 (PDT)
In-Reply-To: <>
References: <> <> <>
Date: Wed, 11 Sep 2013 12:32:40 -0400
X-Google-Sender-Auth: INvwXlEciOoOBehffdxr1jiN6Pg
Message-ID: <>
From: Nick Mathewson <>
To: Eric Rescorla <>
Content-Type: text/plain; charset=ISO-8859-1
Cc:, "" <>
Subject: Re: [TLS] Let's remove gmt_unix_time from TLS
X-Mailman-Version: 2.1.12
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: Wed, 11 Sep 2013 16:32:41 -0000

On Wed, Sep 11, 2013 at 12:06 PM, Eric Rescorla <> wrote:
> Before we discuss mechanisms, it would be good to verify that in general
> clients and servers don't become unhappy if the timestamp is radically
> wrong. Has someone done measurements to verify that this is in fact
> the case at a broad scale?

Tor Browser has omitted this field for over five years now to no ill effect.

It would appear (assuming that I'm reading old NSS source right, which
I might not be!) that from about 2000 to 2008, Firefox was sending the
time since the process started, not the unix time, and nobody noticed
until 2007:

So at least on the client side, there seems to be strong evidence that
sending something other than the correct time does not cause obvious
problems in the wild.