Received: from sog-mx-4.v43.ch3.sourceforge.com ([172.29.43.194] helo=mx.sourceforge.net) by sfs-ml-1.v29.ch3.sourceforge.com with esmtp (Exim 4.76) (envelope-from ) id 1Tg5ml-00046F-LV for bitcoin-development@lists.sourceforge.net; Wed, 05 Dec 2012 03:36:35 +0000 Received-SPF: pass (sog-mx-4.v43.ch3.sourceforge.com: domain of gmail.com designates 209.85.210.180 as permitted sender) client-ip=209.85.210.180; envelope-from=watsonbladd@gmail.com; helo=mail-ia0-f180.google.com; Received: from mail-ia0-f180.google.com ([209.85.210.180]) by sog-mx-4.v43.ch3.sourceforge.com with esmtps (TLSv1:RC4-SHA:128) (Exim 4.76) id 1Tg5mk-0005OJ-PQ for bitcoin-development@lists.sourceforge.net; Wed, 05 Dec 2012 03:36:35 +0000 Received: by mail-ia0-f180.google.com with SMTP id t4so4512598iag.39 for ; Tue, 04 Dec 2012 19:36:29 -0800 (PST) MIME-Version: 1.0 Received: by 10.50.170.66 with SMTP id ak2mr516505igc.38.1354678589515; Tue, 04 Dec 2012 19:36:29 -0800 (PST) Sender: watsonbladd@gmail.com Received: by 10.64.93.231 with HTTP; Tue, 4 Dec 2012 19:36:29 -0800 (PST) In-Reply-To: References: Date: Tue, 4 Dec 2012 21:36:29 -0600 X-Google-Sender-Auth: uY8Bt3OtYnt-2tIQQHKe6Yi2qC0 Message-ID: From: Watson Ladd To: Gregory Maxwell Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-Spam-Score: -1.5 (-) 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 FREEMAIL_FROM Sender email is commonly abused enduser mail provider (watsonbladd[at]gmail.com) -0.0 SPF_PASS SPF: sender matches SPF record 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: 1Tg5mk-0005OJ-PQ Cc: "bitcoin-development@lists.sourceforge.net" Subject: Re: [Bitcoin-development] String-based Hierarchical Deterministic Keys - Alternative to BIP 32 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: Wed, 05 Dec 2012 03:36:35 -0000 On Tue, Dec 4, 2012 at 9:23 PM, Gregory Maxwell wrote: > On Tue, Dec 4, 2012 at 10:06 PM, Mike Koss wrote: >> I've implemented an alternative to the BIP 32 proposal. I wanted a syst= em >> based on a hierarchical string representation (rather than hierarchy of >> integers as BIP 32 proposes). For example I name keys like this: >> >> [hd1.75491111].store.1. 1D7GM5dkUtxvGeWgn7SYtanBuyj1MD1EZy >> [hd1.75491111].store.2. 1QAqDbzpNKViGSjVe1XmnGbmZtvz5hM7t1 >> [hd1.75491111].store.3. 14XkSN92QLGeorYPpoVbG87DQhowEx3mFn >> [hd1.75491111].store.4. 1JLcGdod6Wm33rMZuZZUmAEE6osLhM4QMn >> >> First draft of proposal: >> >> https://gist.github.com/4211704 > > As Pieter pointed out recently=E2=80=94 it's not (realistically) possible= to > blindly iterate through strings. This means your proposal loses the > backup recoverablity property which is part the point of a > deterministic wallet: If you have a backup prior to a new string name > being established you must also have a reliable backup of the string > as well. I would like to note that BIP32 and this new proposal have a missing feature: being able to spend a coin sent to an address generated by this scheme implies being able to spend any coin generated by this scheme. The easiest deterministic wallet construction is simply to use a stream cipher to generate random bytes used as the private keys in a wallet. Hierarchical constructions do not seem to me to add more, other then distinguishing transactions by sending to unique addresses, which could be done by other means. > > Of course, if you're backing up the strings then you can also backup a > map equating the hdwallet indexes to your strings, and in the event of > a catastrophic loss where you are only left with the original ultimate > root you lose no coins (only metadata) with the BIP32 scheme. If, > instead, we have your scheme and the backup of strings is incomplete > then some or all assigned coin may be lost forever. > > Your extended hierarchy of multiplers also makes me uncomfortable. > BIP32 uses a HMAC in its construction to obtain strongly unstructured > points. I read BIP32. And while the multipliers at each level are unstructured, the ones in the next level are products of the ones before i.e. we have a multiplication tree with random looking branches. Note that the order of the basepoint is prime or a small cofactor times a prime, so this isn't an issue (usually: the cofactor could be annoying). -- "Those who would give up Essential Liberty to purchase a little Temporary Safety deserve neither Liberty nor Safety." -- Benjamin Franklin