From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: bruno@wolff.to Received: from wolff.to (wolff.to [98.103.208.27]) by krantz.zx2c4.com (ZX2C4 Mail Server) with SMTP id aca2cb4c for ; Thu, 6 Oct 2016 19:18:00 +0000 (UTC) Date: Thu, 6 Oct 2016 14:27:43 -0500 From: Bruno Wolff III To: "Jason A. Donenfeld" Message-ID: <20161006192743.GA12972@wolff.to> References: <1475719977.650386.747317105.1837502D@webmail.messagingengine.com> <20161006150310.GB30704@wolff.to> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed In-Reply-To: Cc: WireGuard mailing list Subject: Re: [WireGuard] auth-only wireguard List-Id: Development discussion of WireGuard List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Thu, Oct 06, 2016 at 19:32:36 +0200, "Jason A. Donenfeld" wrote: >On Thu, Oct 6, 2016 at 5:03 PM, Bruno Wolff III wrote: >> Without encryption you authentication won't be useful against attackers that >> can modify packets or insert packets with the source address of your >> contact. > >Either I've misunderstood you, or this is completely inaccurate. > >What do you mean exactly? Someone able to watch and modify traffic can wait for authentication to occur and then take over the connection. So you don't know you are still communicating with the party that did the authentication. You need something protecting message integrity which is normally based on encryption, but I think there might be ways to do that with just hashing.