From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from sog-mx-3.v43.ch3.sourceforge.com ([172.29.43.193] helo=mx.sourceforge.net) by sfs-ml-1.v29.ch3.sourceforge.com with esmtp (Exim 4.76) (envelope-from ) id 1YIO9v-0006tI-EI for bitcoin-development@lists.sourceforge.net; Mon, 02 Feb 2015 21:03:51 +0000 Received-SPF: pass (sog-mx-3.v43.ch3.sourceforge.com: domain of gmail.com designates 209.85.192.53 as permitted sender) client-ip=209.85.192.53; envelope-from=brian.erdelyi@gmail.com; helo=mail-qg0-f53.google.com; Received: from mail-qg0-f53.google.com ([209.85.192.53]) by sog-mx-3.v43.ch3.sourceforge.com with esmtps (TLSv1:RC4-SHA:128) (Exim 4.76) id 1YIO9u-0003Fn-5a for bitcoin-development@lists.sourceforge.net; Mon, 02 Feb 2015 21:03:51 +0000 Received: by mail-qg0-f53.google.com with SMTP id a108so49433869qge.12 for ; Mon, 02 Feb 2015 13:03:44 -0800 (PST) X-Received: by 10.224.96.196 with SMTP id i4mr39245631qan.44.1422911024544; Mon, 02 Feb 2015 13:03:44 -0800 (PST) Received: from [192.168.1.58] ([64.147.83.112]) by mx.google.com with ESMTPSA id 107sm19325261qgf.21.2015.02.02.13.03.43 (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Mon, 02 Feb 2015 13:03:43 -0800 (PST) Content-Type: multipart/alternative; boundary="Apple-Mail=_4BBF5A5A-AB52-4F57-94FF-F05D134270D8" Mime-Version: 1.0 (Mac OS X Mail 8.2 \(2070.6\)) From: Brian Erdelyi In-Reply-To: Date: Mon, 2 Feb 2015 17:03:42 -0400 Message-Id: References: <27395C55-CF59-4E65-83CA-73F903272C5F@gmail.com> <54CE3816.6020505@bitwatch.co> <68C03646-02E7-43C6-9B73-E4697F3AA5FD@gmail.com> <57186618-F010-42E6-A757-B617C4001B5B@gmail.com> <4B53C1B0-A677-4460-8A69-C45506424D7F@gmail.com> To: Joel Joonatan Kaartinen X-Mailer: Apple Mail (2.2070.6) X-Spam-Score: -0.6 (/) 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 FREEMAIL_FROM Sender email is commonly abused enduser mail provider (brian.erdelyi[at]gmail.com) -0.0 SPF_PASS SPF: sender matches SPF record 1.0 HTML_MESSAGE BODY: HTML included in message -0.1 DKIM_VALID_AU Message has a valid DKIM or DK signature from author's domain 0.1 DKIM_SIGNED Message has a DKIM or DK signature, not necessarily valid -0.1 DKIM_VALID Message has at least one valid DKIM or DK signature X-Headers-End: 1YIO9u-0003Fn-5a Cc: Bitcoin Dev Subject: Re: [Bitcoin-development] 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: Mon, 02 Feb 2015 21:03:51 -0000 --Apple-Mail=_4BBF5A5A-AB52-4F57-94FF-F05D134270D8 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=utf-8 Joel, The mobile device should show you the details of the transaction (i.e. = amount and bitcoin address). Once you verify this is the intended = recipient and amount you approve it on the mobile device. If the = address was replaced, you should see this on the mobile device as it = won=E2=80=99t match where you were intending to send it. You can then = not provide the second signature. Brian Erdelyi > On Feb 2, 2015, at 4:57 PM, Joel Joonatan Kaartinen = wrote: >=20 > If the attacker has your desktop computer but not the mobile that's = acting as an independent second factor, how are you then supposed to be = able to tell you're not signing the correct transaction on the mobile? = If the address was replaced with the attacker's address, it'll look like = everything is ok. >=20 > - Joel >=20 > On Mon, Feb 2, 2015 at 9:58 PM, Brian Erdelyi > wrote: >=20 > > Confusing or not, the reliance on multiple signatures as offering = greater security than single relies on the independence of multiple = secrets. If the secrets cannot be shown to retain independence in the = envisioned threat scenario (e.g. a user's compromised operating system) = then the benefit reduces to making the exploit more difficult to write, = which, once written, reduces to no benefit. Yet the user still suffers = the reduced utility arising from greater complexity, while being led to = believe in a false promise. >=20 > Just trying to make sure I understand what you=E2=80=99re saying. Are = you eluding to that if two of the three private keys get compromised = there is no gain in security? Although the likelihood of this occurring = is lower, it is possible. >=20 > As more malware targets bitcoins I think the utility is evident. = Given how final Bitcoin transactions are, I think it=E2=80=99s worth = trying to find methods to help verify those transactions (if a user = deems it to be high-risk enough) before the transaction is completed. = The balance is trying to devise something that users do not find too = burdensome. >=20 > Brian Erdelyi > = --------------------------------------------------------------------------= ---- > Dive into the World of Parallel Programming. The Go Parallel Website, > sponsored by Intel and developed in partnership with Slashdot Media, = is your > hub for all things parallel software development, from weekly thought > leadership blogs to news, videos, case studies, tutorials and more. = Take a > look and join the conversation now. http://goparallel.sourceforge.net/ = > _______________________________________________ > Bitcoin-development mailing list > Bitcoin-development@lists.sourceforge.net = > https://lists.sourceforge.net/lists/listinfo/bitcoin-development = >=20 --Apple-Mail=_4BBF5A5A-AB52-4F57-94FF-F05D134270D8 Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=utf-8 Joel,

The = mobile device should show you the details of the transaction (i.e. = amount and bitcoin address).  Once you verify this is the intended = recipient and amount you approve it on the mobile device.  If the = address was replaced, you should see this on the mobile device as it = won=E2=80=99t match where you were intending to send it.  You can = then not provide the second signature.

Brian Erdelyi

On = Feb 2, 2015, at 4:57 PM, Joel Joonatan Kaartinen <joel.kaartinen@gmail.com> wrote:

If the attacker has your desktop computer but not the mobile = that's acting as an independent second factor, how are you then supposed = to be able to tell you're not signing the correct transaction on the = mobile? If the address was replaced with the attacker's address, it'll = look like everything is ok.

- Joel

On Mon, Feb 2, 2015 at 9:58 PM, = Brian Erdelyi <brian.erdelyi@gmail.com> wrote:

> Confusing or not, the reliance on multiple signatures as offering = greater security than single relies on the independence of multiple = secrets. If the secrets cannot be shown to retain independence in the = envisioned threat scenario (e.g. a user's compromised operating system) = then the benefit reduces to making the exploit more difficult to write, = which, once written, reduces to no benefit. Yet the user still suffers = the reduced utility arising from greater complexity, while being led to = believe in a false promise.

Just trying to make sure I understand what you=E2=80=99re = saying.  Are you eluding to that if two of the three private keys = get compromised there is no gain in security?  Although the = likelihood of this occurring is lower, it is possible.

As more malware targets bitcoins I think the utility is evident.  = Given how final Bitcoin transactions are, I think it=E2=80=99s worth = trying to find methods to help verify those transactions (if a user = deems it to be high-risk enough) before the transaction is = completed.  The balance is trying to devise something that users do = not find too burdensome.

Brian Erdelyi
= --------------------------------------------------------------------------= ----
Dive into the World of Parallel Programming. The Go Parallel Website,
sponsored by Intel and developed in partnership with Slashdot Media, is = your
hub for all things parallel software development, from weekly thought
leadership blogs to news, videos, case studies, tutorials and more. Take = a
look and join the conversation now. http://goparallel.sourceforge.net/
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