Received: from sog-mx-3.v43.ch3.sourceforge.com ([172.29.43.193] helo=mx.sourceforge.net) by sfs-ml-2.v29.ch3.sourceforge.com with esmtp (Exim 4.76) (envelope-from ) id 1WTBAf-0001At-16 for bitcoin-development@lists.sourceforge.net; Thu, 27 Mar 2014 14:20:41 +0000 Received-SPF: pass (sog-mx-3.v43.ch3.sourceforge.com: domain of gmail.com designates 209.85.214.169 as permitted sender) client-ip=209.85.214.169; envelope-from=mh.in.england@gmail.com; helo=mail-ob0-f169.google.com; Received: from mail-ob0-f169.google.com ([209.85.214.169]) by sog-mx-3.v43.ch3.sourceforge.com with esmtps (TLSv1:RC4-SHA:128) (Exim 4.76) id 1WTBAc-0005zw-Gh for bitcoin-development@lists.sourceforge.net; Thu, 27 Mar 2014 14:20:40 +0000 Received: by mail-ob0-f169.google.com with SMTP id va2so4285487obc.14 for ; Thu, 27 Mar 2014 07:20:33 -0700 (PDT) MIME-Version: 1.0 X-Received: by 10.60.174.170 with SMTP id bt10mr1658799oec.47.1395930032935; Thu, 27 Mar 2014 07:20:32 -0700 (PDT) Sender: mh.in.england@gmail.com Received: by 10.76.71.231 with HTTP; Thu, 27 Mar 2014 07:20:32 -0700 (PDT) In-Reply-To: <1395928699.5369.99593201.1CFF9238@webmail.messagingengine.com> References: <53340999.807@gmx.de> <5334144A.9040600@gmx.de> <53342C6C.2060006@gmx.de> <1395928699.5369.99593201.1CFF9238@webmail.messagingengine.com> Date: Thu, 27 Mar 2014 15:20:32 +0100 X-Google-Sender-Auth: DFTpZ67KtFdDJUuuqZpG6_H1dgU Message-ID: From: Mike Hearn To: Jim Content-Type: multipart/alternative; boundary=047d7bd6c52cbe9b7304f59749e8 X-Spam-Score: -0.5 (/) 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 (mh.in.england[at]gmail.com) -0.0 SPF_PASS SPF: sender matches SPF record 1.0 HTML_MESSAGE BODY: HTML included in message 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: 1WTBAc-0005zw-Gh Cc: Bitcoin Dev Subject: Re: [Bitcoin-development] New BIP32 structure 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: Thu, 27 Mar 2014 14:20:41 -0000 --047d7bd6c52cbe9b7304f59749e8 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable For SPV wallets it's more complicated. There must always be a large lookahead window for latency reasons. We can't query the entire database because we don't know how far ahead the user is. So we have to assume there might be a lot of transaction traffic and create a large window, to reduce the chances that we run out whilst syncing and have to abort/restart the sync after resetting the Bloom filter. If you have a full db index then you can calculate some addresses, query, if they all get hits, calculate some more, requery, etc. It's a bit simpler= . On Thu, Mar 27, 2014 at 2:58 PM, Jim wrote: > Good to hear the bip32 wallet structure is _so_ close to being > standardised. > For MultiBit HD, we have put in support for 12/18/24 words but have the U= I > 'suggest' to use 12. > You can see this on the wallet creation wizard Gary recently blogged abou= t: > https://multibit.org/blog/2014/03/26/multibit-hd-welcome-wizard.html > > There's a little combo for the seed length, with 12 as the default. > > > @Thomas. You mention gaps. We are creating new addresses on the UI in a > panel marked 'Request' where the user also types in a QR code label and a > note to themselves. This gets stored away as a first class > 'PaymentRequest'. The UI 'suggests' that each address is used once. There > will be some gaps (where the payment request is never paid) but we aren't > bulk creating addresses. I am hoping this shouldn't cause Electrum a > problem. > > We are also storing a timestamp (the number of days since the genesis > block) to help wallet restore but that is SPV specific. > > > On Thu, Mar 27, 2014, at 01:49 PM, Thomas Voegtlin wrote: > > > > > > Le 27/03/2014 13:49, Mike Hearn a =C3=A9crit : > IP32 allows for a range of entropy sizes and it so happens that > > > they picked 256 bits instead of 128 bits. > > > > > > I'd have thought that there is a right answer for this. 2^128 should > not > > > be brute forceable, and longer sizes have a cost in terms of making t= he > > > seeds harder to write down on paper. So should this be a degree of > freedom? > > > > > > > > > Here is what I understand: > > > > 2^128 iterations is not brute forcable today, and will not be for the > > foreseeable future. > > > > An EC pubkey of length n can be forced in approximately 2^(n/2) > > iterations (see http://ecc-challenge.info/) Thus, Bitcoin pubkeys, whic= h > > are 256 bits, would require 2^128 iterations. This is why unused > > addresses (160 bits hash) are better protected than already used ones. > > > > However, people tend to believe that a public key of size n requires 2^= n > > iterations. This belief might have been spread by this popular image: > > https://bitcointalk.org/index.php?topic=3D508880.msg5616146#msg5616146 > > > > > > > -------------------------------------------------------------------------= ----- > > _______________________________________________ > > Bitcoin-development mailing list > > Bitcoin-development@lists.sourceforge.net > > https://lists.sourceforge.net/lists/listinfo/bitcoin-development > > > -- > http://bitcoin-solutions.co.uk > > > -------------------------------------------------------------------------= ----- > _______________________________________________ > Bitcoin-development mailing list > Bitcoin-development@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/bitcoin-development > --047d7bd6c52cbe9b7304f59749e8 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
For SPV wallets it's more complicated. There must alwa= ys be a large lookahead window for latency reasons. We can't query the = entire database because we don't know how far ahead the user is. So we = have to assume there might be a lot of transaction traffic and create a lar= ge window, to reduce the chances that we run out whilst syncing and have to= abort/restart the sync after resetting the Bloom filter.

If you have a full db index then you can calculate some addr= esses, query, if they all get hits, calculate some more, requery, etc. It&#= 39;s a bit simpler.


On Thu, Mar 27, 2014 at 2:58 PM, Jim <jim618@fastmail.co.uk> wrote:
Good to hear the bip32 wallet structure is _so_ close to being standardised= .
For MultiBit HD, we have put in support for 12/18/24 words but have the UI = 'suggest' to use 12.
You can see this on the wallet creation wizard Gary recently blogged about:=
https://multibit.org/blog/2014/03/26/multibit-hd-we= lcome-wizard.html

There's a little combo for the seed length, with 12 as the default.


@Thomas. You mention gaps. We are creating new addresses on the UI in a pan= el marked 'Request' where the user also types in a QR code label an= d a note to themselves. This gets stored away as a first class 'Payment= Request'. The UI 'suggests' that each address is used once. The= re will be some gaps (where the payment request is never paid) but we aren&= #39;t bulk creating addresses. I am hoping this shouldn't cause Electru= m a problem.

We are also storing a timestamp (the number of days since the genesis block= ) to help wallet restore but that is SPV specific.


On Thu, Mar 27, 2014, at 01:49 PM, Thomas Voegtlin wrote:
>
>
> Le 27/03/2014 13:49, Mike Hearn a =C3=A9crit :
IP32 allows for a range of en= tropy sizes and it so happens that
> > they picked 256 bits instead of 128 bits.
> >
> > I'd have thought that there is a right answer for this. 2^128= should not
> > be brute forceable, and longer sizes have a cost in terms of maki= ng the
> > seeds harder to write down on paper. So should this be a degree o= f freedom?
> >
>
>
> Here is what I understand:
>
> 2^128 iterations is not brute forcable today, and will not be for the<= br> > foreseeable future.
>
> An EC pubkey of length n can be forced in approximately 2^(n/2)
> iterations (see http://ecc-challenge.info/) Thus, Bitcoin pubkeys, which
> are 256 bits, would require 2^128 iterations. This is why unused
> addresses (160 bits hash) are better protected than already used ones.=
>
> However, people tend to believe that a public key of size n requires 2= ^n
> iterations. This belief might have been spread by this popular image:<= br> > https://bitcointalk.org/index.php?topic=3D50= 8880.msg5616146#msg5616146
>
>
> ----------------------------------------------------------------------= --------
> _______________________________________________
> Bitcoin-development mailing list
> Bitcoin-d= evelopment@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/bitco= in-development


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