Ah, BIP32 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 the seeds harder to write down on paper. So should this be a degree of freedom? On Thu, Mar 27, 2014 at 1:28 PM, Mike Hearn wrote: > By the way, I just noticed that greenaddress.it is creating seeds that > have 24 words instead of 12. Does anyone know what's up with that? They > claim to be using BIP32 wallets so I wanted to see if they were using the > default structure and if so, whether bitcoinj was compatible with it > (before I switch to the one discussed here). But it seems we fall at the > first hurdle ... > > > On Thu, Mar 27, 2014 at 1:06 PM, Thomas Voegtlin wrote: > >> >> >> Le 27/03/2014 12:30, Marek Palatinus a écrit : >> > Ah, I forget to two things, which should be into the BIP as well: >> > >> > a) Gap factor for addresses; as Thomas mentioned, although some software >> > can watch almost unlimited amount of unused addresses, this is serious >> > concern for lightweight or server-based wallets like Electrum or >> > myTREZOR. myTREZOR currently uses gap factor 10, which is (from my >> > experience so far) quite sane for most of users. >> >> >> Yes, I was planning to increase the number of available unused addresses >> to 10 or 20 in the bip32 version of Electrum. >> >> Related to this, here is another idea I would like to submit: >> >> Instead of using a "gap limit" (maximal number of consecutive unused >> addresses), I think we should get rid of the topology, and simply count >> the number of unused addresses since the beginning of the sequence. >> Indeed, the topology of the sequence of addresses is of no interest to >> the user. Users often misinterpret "gap limit" as the "number of unused >> addresses available", so I think we should just give them what they want >> :) This is easier to understand, and it makes things more predictable, >> because the wallet will always display the same number of unused >> addresses (except when it is waiting for confirmations). >> >> >> >> ------------------------------------------------------------------------------ >> _______________________________________________ >> Bitcoin-development mailing list >> Bitcoin-development@lists.sourceforge.net >> https://lists.sourceforge.net/lists/listinfo/bitcoin-development >> > >