From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from sog-mx-1.v43.ch3.sourceforge.com ([172.29.43.191] helo=mx.sourceforge.net) by sfs-ml-4.v29.ch3.sourceforge.com with esmtp (Exim 4.76) (envelope-from ) id 1YImQE-0001y8-I5 for bitcoin-development@lists.sourceforge.net; Tue, 03 Feb 2015 22:58:18 +0000 Received-SPF: pass (sog-mx-1.v43.ch3.sourceforge.com: domain of novauri.com designates 209.85.213.179 as permitted sender) client-ip=209.85.213.179; envelope-from=will.madden@novauri.com; helo=mail-ig0-f179.google.com; Received: from mail-ig0-f179.google.com ([209.85.213.179]) by sog-mx-1.v43.ch3.sourceforge.com with esmtps (TLSv1:RC4-SHA:128) (Exim 4.76) id 1YImQD-0002OY-1F for bitcoin-development@lists.sourceforge.net; Tue, 03 Feb 2015 22:58:18 +0000 Received: by mail-ig0-f179.google.com with SMTP id l13so2157iga.0 for ; Tue, 03 Feb 2015 14:58:11 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:date:from:to:cc:message-id:in-reply-to :references:subject:mime-version:content-type; bh=EcN0dOaLX7reJGFDBYd60nnVweBGpJHnDWB6u97neDc=; b=dIzIvk1G/lsIobA40NaKjZBqWWIv3V0zcZP2XAEGVUW72qn00m/MHpTpkidReYcNKy 0YQdZGWXR5cqF4U2mrwM7bzkGxI6N9z0KfuMa+A5M+9Lt0DDeclWQFKwQkbeaMvPVOyU giJGR3+8N5v37CMu4siak2Zh0cnH75uWfbaMbiqbqdEDw0dwSR8qNFWOhmTga9C8YUS4 PreM+5L1Kz9xNthXvc4iJfrCUMO0iGn1g4rCt4DQSp5dEm57aEXrj23R2w28vW9dbcg4 JhYZBUV5AVfJwzfDQpugu0E/WuSmzO+qmhh1XlrE1rFrgRfT3Llv5T3eGKO7jrFxoGl3 4SAg== X-Gm-Message-State: ALoCoQkv+tTi3VntLyo2njNzvKsdrebxkwXzCgWXtnTMY/9Ttrosazgmw9+w0eNtckTRm1fiqKPq X-Received: by 10.42.95.12 with SMTP id d12mr26681315icn.12.1423004291707; Tue, 03 Feb 2015 14:58:11 -0800 (PST) Received: from Williams-MBP (c-107-2-216-154.hsd1.co.comcast.net. [107.2.216.154]) by mx.google.com with ESMTPSA id kz4sm8644185igb.17.2015.02.03.14.58.10 (version=TLSv1.2 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Tue, 03 Feb 2015 14:58:11 -0800 (PST) Date: Tue, 3 Feb 2015 15:58:10 -0700 From: Will To: Adam Weiss Message-ID: In-Reply-To: References: X-Mailer: Airmail (286) MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="54d15282_109cf92e_8c05" X-Spam-Score: -0.5 (/) X-Spam-Report: Spam Filtering performed by mx.sourceforge.net. See http://spamassassin.org/tag/ for more details. -1.5 SPF_CHECK_PASS SPF reports sender host as permitted sender for sender-domain -0.0 SPF_PASS SPF: sender matches SPF record 1.0 HTML_MESSAGE BODY: HTML included in message X-Headers-End: 1YImQD-0002OY-1F Cc: bitcoin-development@lists.sourceforge.net Subject: Re: [Bitcoin-development] Subject: Re: Proposal to address Bitcoin malware X-BeenThere: bitcoin-development@lists.sourceforge.net X-Mailman-Version: 2.1.9 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 03 Feb 2015 22:58:18 -0000 --54d15282_109cf92e_8c05 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Content-Disposition: inline Hi Adam - the conversation was pretty open regarding the factor / channel= used to sign at the bottom. =C2=A0No argument from me and I agree comple= tely that hardened single purpose computers are more secure than desktop = browsers, browser extensions, SMS, or mobile apps when involved in multis= ig authorization. =C2=A0The point below was that risks with other channel= s are far higher if auth data is input from two channels through one, suc= h as entering a 2=46A phone token and desktop password into the same desk= top browser session - MITM phishing attack on websites that bypasses phon= e 2=46A as an example, serendipitously timed yet tragic example of this s= cam with coinbase today:=C2=A0https://www.reddit.com/r/Bitcoin/comments/2= ungby/fuck=5Fi=5Fjust=5Fgot=5Fscammed/ On the topic of hardened single purpose computers, and I mean no offense = to our friends at Trezor, Case, or similar but I think the future of this= type of security approach with bitcoin is extremely bright. =C2=A0It=E2=80= =99s just far more likely to involve chips integrated directly in PC / Ma= c motherboards and mobile devices / wearables where signing is done in th= e hardware inaccessible to the OS or BIOS. =C2=A0This is a way for mainst= ream users to use bitcoin securely, integrate it with apps running from p= opular OS=E2=80=99s and get bitcoin into the internet on a very granular = level, and Joe six pack and Sally soccer mom never even know they are usi= ng multisig. =C2=A0It took 20+ years for people to get used to cards vs. = cash. =C2=A0The telephone took 50 years to catch on and become cost compe= titive. I think the key is making it invisible to the user. =46rom:=C2=A0Adam Weiss Reply:=C2=A0Adam Weiss > Date:=C2=A0=46ebruary 3, 2015 at 12:25:20 PM To:=C2=A0Will > Cc:=C2=A0bitcoin-development=40lists.sourceforge.net > Subject:=C2=A0 Re: =5BBitcoin-development=5D Subject: Re: Proposal to add= ress Bitcoin malware =20 Using a desktop website and mobile device for 2/3 multisig in lieu of a h= ardware device (trezor) and desktop website (mytrezor) works, but the key= is that the device used to input the two signatures=C2=A0cannot be in th= e same band.=C2=A0 What you are protecting against are MITM attacks.=C2=A0= The issue is that if a single=C2=A0device or network is compromised by m= alware, or if a party is connecting to a counterparty through a channel w= ith compromised security, inputing 2 signatures through the=C2=A0same dev= ice/band defeats=C2=A0the purpose of 2/3 multisig. =C2=A0 Maybe I'm not following the conversation very well, but if you have a sma= ll hardware device that first displays a signed payment request (BIP70) a= nd then only will sign what is displayed, how can a MITM attacker do anyt= hing other than deny service=3F=C2=A0 They'd have to get malware onto the= signing device, which is the vector that a simplified signing device is = specifically designed to mitigate. TREZOR like devices with BIP70 support and third party cosigning services= are a solution I really like the sound of.=C2=A0 I suppose though that a= dding BIP70 request signature validation and adding certificate revocatio= n support starts to balloon the scope of what is supposed to be a very si= mple device though. Regardless, I think a standard for passing partially signed transactions = around might make sense (maybe a future extension to BIP70), with attenti= on to both PC <-> small hardware devices and pushing stuff around on the = Internet.=C2=A0 It would be great if users had a choice of hardware signi= ng devices, local software and third-party cosigning services that would = all interoperate out of the box to enable easy multisig security, which i= n the BTC world subsumes the goals of 2=46A. --adam --54d15282_109cf92e_8c05 Content-Type: text/html; charset="utf-8" Content-Transfer-Encoding: quoted-printable Content-Disposition: inline