Received: from sog-mx-2.v43.ch3.sourceforge.com ([172.29.43.192] helo=mx.sourceforge.net) by sfs-ml-4.v29.ch3.sourceforge.com with esmtp (Exim 4.76) (envelope-from ) id 1YVw8S-0007EH-LS for bitcoin-development@lists.sourceforge.net; Thu, 12 Mar 2015 05:58:20 +0000 Received: from nm40-vm6.bullet.mail.bf1.yahoo.com ([72.30.239.214]) by sog-mx-2.v43.ch3.sourceforge.com with esmtps (TLSv1:RC4-SHA:128) (Exim 4.76) id 1YVw8Q-0003MB-LW for bitcoin-development@lists.sourceforge.net; Thu, 12 Mar 2015 05:58:20 +0000 Received: from [98.139.214.32] by nm40.bullet.mail.bf1.yahoo.com with NNFMP; 12 Mar 2015 05:58:13 -0000 Received: from [98.139.215.253] by tm15.bullet.mail.bf1.yahoo.com with NNFMP; 12 Mar 2015 05:58:13 -0000 Received: from [127.0.0.1] by omp1066.mail.bf1.yahoo.com with NNFMP; 12 Mar 2015 05:58:13 -0000 X-Yahoo-Newman-Property: ymail-3 X-Yahoo-Newman-Id: 327541.92453.bm@omp1066.mail.bf1.yahoo.com X-YMail-OSG: DdphZO0VM1kAYZE0FkPCZe7tmaJZthN.fthT0Q7srVEeYf6f0cLXSoGbuMyKClA w2RkPwLA7NVaZiHje_E60QdHuYKCHQ07n85Aise_a5JtAgzd43nXBn2DcUT54qzIjlN.gDtYAygC IZA0ed_KO1KH88.PEI27NoyHomNEZvKg4H20dJ7yzmB7ON4.j4UXZ40EdbNW04tN2jLtXr1izb1D vSY7uTFBtY7C4JVe8IM_IkVQjxVU5tWLk2MKBFwl8mceMkmYNPK.Zo0Iq8NM5fcZ7PcgPA5e8JMc l6FqzM_JEs5hQs3IJQ1delrDl_92kCBArHVC65glWvRd.pUB8qcN9npYE3jsj9YZ4GnCsIBKKLuX x7OOVlI2bb8MtwN_KlIF3D.4f36vf_GqRuVwDGiEMwVI8lqj1ySS9GmCgpbmTIj9KfnBJOkUKG0r qHYHxN3WVcxSVMJoRZQ.PnHwB6d63l_sGTxcvVd_3qNa9I_xKVoTrFs0glpT1cuFrIaPnT6LEDez dLhVa546SRCsWAyYppwNIuNKN4fJKiwUDfYd6ALO4mOwwtxomqt3UbF6H_b4ALIOcDgOclLdxcw3 fXt3G9t8_sw-- Received: by 76.13.26.64; Thu, 12 Mar 2015 05:58:12 +0000 Date: Thu, 12 Mar 2015 05:58:12 +0000 (UTC) From: Thy Shizzle To: "voisine@gmail.com" Message-ID: <1511245342.4538047.1426139892373.JavaMail.yahoo@mail.yahoo.com> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_Part_4538046_1837632964.1426139892370" X-Spam-Score: 1.2 (+) X-Spam-Report: Spam Filtering performed by mx.sourceforge.net. See http://spamassassin.org/tag/ for more details. 0.0 FREEMAIL_FROM Sender email is commonly abused enduser mail provider (harro84[at]yahoo.com.au) 0.2 FREEMAIL_ENVFROM_END_DIGIT Envelope-from freemail username ends in digit (harro84[at]yahoo.com.au) -0.0 RCVD_IN_DNSWL_NONE RBL: Sender listed at http://www.dnswl.org/, no trust [72.30.239.214 listed in list.dnswl.org] 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 0.0 AWL AWL: Adjusted score from AWL reputation of From: address X-Headers-End: 1YVw8Q-0003MB-LW Cc: "bitcoin-development@lists.sourceforge.net" Subject: Re: [Bitcoin-development] Electrum 2.0 has been tagged X-BeenThere: bitcoin-development@lists.sourceforge.net X-Mailman-Version: 2.1.9 Precedence: list Reply-To: Thy Shizzle List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 12 Mar 2015 05:58:20 -0000 ------=_Part_4538046_1837632964.1426139892370 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable =C2=A0 Why on earth would you want to derive the mnemonic from the wallet s= eed? Ever? Remembering that as an attacker doesn't actually have to do any key stretch= ing, they can just keep trying (what is it 64 bytes from memory?) at a time= without any PBKDF2 to attack a seed, it seems that the PBKDF2 is just to s= low down anyone attempting to attack through an interface such as a web ser= vice or to a TREZOR or whatever, in a real world attack you would not even = be performing PBKDF2 you would just brute force the raw bytes and=C2=A0forc= e them into the BIP32 wallet=C2=A0as there is no Authentication scheme that= hashes and compares against the result. It purely limits abuse through an = online wallet provider or something like that by slowing down seed generati= on attempts THROUGH that API, it doesn't really add any security to the see= d in a real world brute force attack! So yea I think the 2048 iteration cou= nt is sufficient for it's purpose because even if it only forces an extra 1= ms per seed generation through the API, it is still slower than just brute = forcing the 64 bytes straight up, and so they would have no reason to abuse= your API that is all :) "meh... the fact that you can't derive the seed phrase from the wallet seed= , and that the password key stretching is so weak as to be ineffectual secu= rity theater bugs me. Feels like a pretty big compromise to work on current= generation low power embedded devices when the next generation will be mor= e than capable. But I understand the motivation for the compromise. Aaron Voisine co-founder and CEO breadwallet.com" ------=_Part_4538046_1837632964.1426139892370 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
 
Why on earth would= you want to derive the mnemonic from the wallet seed? Ever?

Remembe= ring that as an attacker doesn't actually have to do any key stretching, th= ey can just keep trying (what is it 64 bytes from memory?) at a time withou= t any PBKDF2 to attack a seed, it seems that the PBKDF2 is just to slow dow= n anyone attempting to attack through an interface such as a web service or= to a TREZOR or whatever, in a real world attack you would not even be perf= orming PBKDF2 you would just brute force the raw bytes and force them = into the BIP32 wallet as there is no Authentication scheme that hashes= and compares against the result. It purely limits abuse through an online = wallet provider or something like that by slowing down seed generation atte= mpts THROUGH that API, it doesn't really add any security to the seed in a = real world brute force attack! So yea I think the 2048 iteration count is s= ufficient for it's purpose because even if it only forces an extra 1ms per = seed generation through the API, it is still slower than just brute forcing= the 64 bytes straight up, and so they would have no reason to abuse your A= PI that is all :)

"meh... the fact that you can't derive the seed phras= e from the wallet seed, and that the password key stretching is so weak as = to be ineffectual security theater bugs me. Feels like a pretty big comprom= ise to work on current generation low power embedded devices when the next = generation will be more than capable. But I understand the motivation for t= he compromise.

Aaron Voisine
co-founder and CEO
breadwallet.com= "
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