Received: from sog-mx-1.v43.ch3.sourceforge.com ([172.29.43.191] helo=mx.sourceforge.net) by sfs-ml-1.v29.ch3.sourceforge.com with esmtp (Exim 4.76) (envelope-from ) id 1Xb8Lw-0003Yf-8i for bitcoin-development@lists.sourceforge.net; Mon, 06 Oct 2014 13:29:28 +0000 X-ACL-Warn: Received: from wp059.webpack.hosteurope.de ([80.237.132.66]) by sog-mx-1.v43.ch3.sourceforge.com with esmtps (TLSv1:AES256-SHA:256) (Exim 4.76) id 1Xb8Lu-0006tg-NF for bitcoin-development@lists.sourceforge.net; Mon, 06 Oct 2014 13:29:28 +0000 Received: from wsip-70-165-172-128.lv.lv.cox.net ([70.165.172.128]); authenticated by wp059.webpack.hosteurope.de running ExIM with esmtpsa (TLS1.0:RSA_AES_128_CBC_SHA1:16) id 1Xb8Lo-0005TB-2N; Mon, 06 Oct 2014 15:29:20 +0200 Content-Type: multipart/signed; boundary="Apple-Mail=_E004C6E5-9CF2-4FE7-922F-6B04DB5A90CC"; protocol="application/pgp-signature"; micalg=pgp-sha512 Mime-Version: 1.0 (Mac OS X Mail 7.3 \(1878.6\)) From: Tamas Blummer In-Reply-To: <5432974B.4000606@certimix.com> Date: Mon, 6 Oct 2014 06:29:15 -0700 Message-Id: References: <5431CD8D.7050508@certimix.com> <5432974B.4000606@certimix.com> To: Sergio Lerner X-Mailer: Apple Mail (2.1878.6) X-bounce-key: webpack.hosteurope.de; tamas@bitsofproof.com; 1412602166; bfd33070; X-Spam-Score: 0.0 (/) X-Spam-Report: Spam Filtering performed by mx.sourceforge.net. See http://spamassassin.org/tag/ for more details. -0.0 RCVD_IN_DNSWL_NONE RBL: Sender listed at http://www.dnswl.org/, no trust [80.237.132.66 listed in list.dnswl.org] X-Headers-End: 1Xb8Lu-0006tg-NF Cc: bitcoin-development@lists.sourceforge.net Subject: Re: [Bitcoin-development] The Bitcoin Freeze on Transaction Attack (FRONT) 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, 06 Oct 2014 13:29:28 -0000 --Apple-Mail=_E004C6E5-9CF2-4FE7-922F-6B04DB5A90CC Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=windows-1252 Sergio, you can call this an ORBS attack or an attempt of ad-hoc coalition = forming for a fork. Preparation Step: Include a transaction sending a sizable amount between two of your own = addresses in every block. Miner can do this at zero cost in their own blocks. Execution: Embed into the preferred fork a transaction double spending the regular = do-nothing transaction with one that offers a sufficiently high fee. = This offers inceptive to rational miner to join the ad-hoc coalition for = that fork. Attempting to form an ad-hoc coalition using above steps is open to = anyone, just cheaper and easier to execute for a miner.=20 Fortunately cost for (cumulative) proof-of-work creates a lower bound to = the incentive that need to be offered. So your worry of times where block subsidy is low is unwarranted as cost of POW will = be high. I do not think =93disallowing=94 the implementation of rational mining = is a viable option, since no one needs permission to implement whatever = optimization he thinks is profitable and within the rules. Tamas Blummer --Apple-Mail=_E004C6E5-9CF2-4FE7-922F-6B04DB5A90CC Content-Transfer-Encoding: 7bit Content-Disposition: attachment; filename=signature.asc Content-Type: application/pgp-signature; name=signature.asc Content-Description: Message signed with OpenPGP using GPGMail -----BEGIN PGP SIGNATURE----- Comment: GPGTools - https://gpgtools.org iQEcBAEBCgAGBQJUMpkrAAoJEPZykcUXcTkc5YMH/jnwsPZ7QDKUBbCyjnLbNPqL lyFgJvElDSbWuLZTKRWExGchze5lWhH5hTHSm9eKrkV88C5FSSW28gL7to6F7dYG Zbwyk0b/J5OA+Qzgn2+LuovBJXVii/TtPBnLNHHOuYTSaAaUiQEPy6+Je3R6fOf5 kPmRWV5LMRLsOlROqs+8ubk+/xBOHjpHdzfglCjfnCtmj+s8BeNesST/udURtbAj d5wiPSkoRSHyJtSporxG78HOF7t0stqVLYhUtBZQ6liLsKEiQrh0Pgo8VoIRDkIA N1ixYSU0i58bxTJdpVuO3FSkTwhUvpL/VZ2pVNGHW6kPTjUizGqpfwiYN2rm25Y= =9rZa -----END PGP SIGNATURE----- --Apple-Mail=_E004C6E5-9CF2-4FE7-922F-6B04DB5A90CC--