From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from sog-mx-2.v43.ch3.sourceforge.com ([172.29.43.192] helo=mx.sourceforge.net) by sfs-ml-1.v29.ch3.sourceforge.com with esmtp (Exim 4.76) (envelope-from ) id 1YHtxj-0003nb-9s for bitcoin-development@lists.sourceforge.net; Sun, 01 Feb 2015 12:49:15 +0000 Received-SPF: pass (sog-mx-2.v43.ch3.sourceforge.com: domain of gmail.com designates 209.85.192.45 as permitted sender) client-ip=209.85.192.45; envelope-from=brian.erdelyi@gmail.com; helo=mail-qg0-f45.google.com; Received: from mail-qg0-f45.google.com ([209.85.192.45]) by sog-mx-2.v43.ch3.sourceforge.com with esmtps (TLSv1:RC4-SHA:128) (Exim 4.76) id 1YHtxh-000149-J4 for bitcoin-development@lists.sourceforge.net; Sun, 01 Feb 2015 12:49:15 +0000 Received: by mail-qg0-f45.google.com with SMTP id q107so44152053qgd.4 for ; Sun, 01 Feb 2015 04:49:08 -0800 (PST) X-Received: by 10.229.174.70 with SMTP id s6mr31330482qcz.7.1422794948175; Sun, 01 Feb 2015 04:49:08 -0800 (PST) Received: from [192.168.1.58] ([64.147.83.112]) by mx.google.com with ESMTPSA id 78sm15383899qgi.38.2015.02.01.04.49.06 (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Sun, 01 Feb 2015 04:49:07 -0800 (PST) Content-Type: multipart/alternative; boundary="Apple-Mail=_9DC5231B-226F-4B81-9007-F1D7B91A1D6C" Mime-Version: 1.0 (Mac OS X Mail 8.2 \(2070.6\)) From: Brian Erdelyi In-Reply-To: Date: Sun, 1 Feb 2015 08:49:05 -0400 Message-Id: <88211D58-DE9D-4B4A-B3A5-2EEFDFC5E02B@gmail.com> References: <27395C55-CF59-4E65-83CA-73F903272C5F@gmail.com> <1348028F-26F8-42CB-9859-C9CB751BF0C9@gmail.com> To: Natanael 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: 1YHtxh-000149-J4 Cc: bitcoin-development@lists.sourceforge.net 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: Sun, 01 Feb 2015 12:49:15 -0000 --Apple-Mail=_9DC5231B-226F-4B81-9007-F1D7B91A1D6C Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=utf-8 In online banking, the banks generate account numbers. An attacker = cannot generate their own account number and the likelihood of an = attacker having the same account number that I am trying to transfer = funds to is low and this is why OCRA is effective with online banking. With Bitcoin, the Bitcoin address is comparable to the recipient=E2=80=99s= bank account number. I now see how an an attacker can brute force the = bitcoin address with vanitygen. Is there any way to generate an 8 digit = number from the bitcoin address that can be used to verify transactions = in such a way (possibly with hashing?) that brute forcing a bitcoin = address would take longer than a reasonable period of time (say 60 = seconds) so a system could time out if a transaction was not completed = in that time? I=E2=80=99ve also looked into BIP70 (Payment Protocol) that claims = protection against man-in-the-middle/man-in-the-browser (MitB) based = attacks. A common way to protect against this is with out-of-band = transaction verification = (http://en.wikipedia.org/wiki/Man-in-the-browser#Out-of-band_transaction_v= erification = ). I see how BIP 70 verifies the payment request, however, = is there any way to verify that the transaction signed by the wallet = matches the request before it is sent to the blockchain (and how can = this support out of band verification)? Perhaps this is something that = can only be supported when sending money with web based wallets. Brian Erdelyi= --Apple-Mail=_9DC5231B-226F-4B81-9007-F1D7B91A1D6C Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=utf-8

In = online banking, the banks generate account numbers.  An attacker = cannot generate their own account number and the likelihood of an = attacker having the same account number that I am trying to transfer = funds to is low and this is why OCRA is effective with online = banking.

With = Bitcoin, the Bitcoin address is comparable to the recipient=E2=80=99s = bank account number.   I now see how an an attacker can brute force = the bitcoin address with vanitygen.  Is there any way to generate = an 8 digit number from the bitcoin address that can be used to verify = transactions in such a way (possibly with hashing?) that brute forcing a = bitcoin address would take longer than a reasonable period of time (say = 60 seconds) so a system could time out if a transaction was not = completed in that time?

I=E2=80=99ve also looked into BIP70 (Payment Protocol) that = claims protection against man-in-the-middle/man-in-the-browser (MitB) = based attacks.  A common way to protect against this is with = out-of-band transaction verification (http://en.wikipedia.org/wiki/Man-in-the-browser#Out-of-band_tra= nsaction_verification).  I see how BIP 70 verifies the payment = request, however, is there any way to verify that the transaction signed = by the wallet matches the request before it is sent to the blockchain = (and how can this support out of band verification)?  Perhaps this = is something that can only be supported when sending money with web = based wallets.

Brian Erdelyi
= --Apple-Mail=_9DC5231B-226F-4B81-9007-F1D7B91A1D6C--