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From: Mike Hearn <mike@plan99.net>
To: Thomas Voegtlin <thomasv1@gmx.de>
Cc: Bitcoin Dev <bitcoin-development@lists.sourceforge.net>
Subject: Re: [Bitcoin-development] New BIP32 structure
Date: Thu, 27 Mar 2014 12:39:21 +0100	[thread overview]
Message-ID: <CANEZrP1v7ZCmhhoHmuXXXvKwAV1_0a02Vkf9z4nQGNfAbZBM=A@mail.gmail.com> (raw)
In-Reply-To: <53340426.4040208@gmx.de>

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>
> One issue that I have is bandwidth: Electrum (and mycelium) cannot
> watch as many addresses as they want, because this will create too
> much traffic on the servers. (especially when servers send utxo merkle
> proofs for each address, which is not the case yet, but is planned)
>

This is surprising and the first time I've heard about this. Surely your
constraint is CPU or disk seeks? Addresses are small, I find it hard to
believe that clients uploading them is a big drain, and mostly addresses
that are in the lookahead region won't have any hits and so won't result in
any downloads?

This constraint is not so important for bloom-filter clients.


Bloom filters are a neat way to encode addresses and keys but they don't
magically let clients save bandwidth. A smaller filter results in less
upload bandwidth but more download (from the wallets perspective). So I'm
worried if you think this will be an issue for your clients: I haven't
investigated bandwidth usage deeply yet, perhaps I should.

FWIW the current bitcoinj HDW alpha preview pre-gens 100 addresses on both
receive and change branches. But I'm not sure what the right setting is.

We also have to consider latency. The simplest implementation from a
wallets POV is to step through each transaction in the block chain one at a
time, and each time you see an address that is yours, calculate the next
ones in the chain. But that would be fantastically slow, so we must instead
pre-generate a larger lookahead region and request more data in one batch.
Then you have to recover if that batch ends up using all the pre-genned
addresses. It's just painful.


> My opinion, as far as Electrum is concerned, is that merchant accounts
> should behave differently from regular user accounts: While merchants
> need to generate an unlimited number of receiving addresses, it is also
> acceptable for them to have a slightly more complex wallet recovery
> procedure
>

Maybe. I dislike any distinction between users and merchants though. I
don't think it's really safe to assume merchants are more sophisticated
than end users.


> but also because we want fully automated synchronization between different
> instances of a wallet, using only no other source of information than
> the blockchain.
>

I think such synchronization won't be possible as we keep adding features,
because the block chain cannot sync all the relevant data. For instance
Electrum already has a label sync feature. Other wallets need to compete
with that, somehow, so we need to build a way to do cross-device wallet
sync with non-chain data.

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  reply	other threads:[~2014-03-27 11:39 UTC|newest]

Thread overview: 100+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-03-26 20:49 [Bitcoin-development] New BIP32 structure Mike Hearn
2014-03-26 23:37 ` Andreas Schildbach
2014-03-27  1:01   ` Alan Reiner
2014-03-27  6:15     ` Mike Belshe
2014-03-27 10:57   ` Thomas Voegtlin
2014-03-27 11:39     ` Mike Hearn [this message]
2014-03-27 13:30       ` Thomas Voegtlin
2014-03-27 13:38         ` Mike Hearn
2014-03-27  1:13 ` Allen Piscitello
2014-03-27  5:34 ` Troy Benjegerdes
2014-03-27  7:09 ` Tamas Blummer
2014-03-27  9:42   ` Mike Hearn
2014-03-27 11:35   ` Pavol Rusnak
2014-03-27 15:43   ` Jeff Garzik
2014-03-27 15:57     ` Allen Piscitello
2014-03-27 16:06       ` Pavol Rusnak
2014-03-27 16:13         ` Allen Piscitello
2014-03-27 16:07       ` Tamas Blummer
2014-03-27 16:14       ` Pieter Wuille
2014-03-27 16:21         ` Pavol Rusnak
2014-03-27 16:28           ` Pieter Wuille
2014-03-27 17:49             ` Allen Piscitello
2014-03-28 14:59             ` slush
2014-04-08 12:43               ` slush
2014-04-08 13:18                 ` Pieter Wuille
2014-04-08 13:40                   ` slush
2014-04-08 13:43                     ` slush
2014-04-08 13:53                       ` Pieter Wuille
2014-04-08 13:59                         ` Thomas Voegtlin
2014-04-08 14:00                         ` Tamas Blummer
2014-04-08 14:35                         ` Pavol Rusnak
2014-04-08 15:41                         ` slush
2014-04-23 17:42                           ` Pieter Wuille
2014-04-23 18:01                             ` slush
2014-04-23 18:18                               ` slush
2014-04-23 18:39                                 ` Tier Nolan
2014-04-23 18:46                                   ` Pavol Rusnak
2014-04-23 19:00                                     ` Tier Nolan
2014-04-23 19:06                                       ` slush
2014-04-23 19:36                                         ` Tamas Blummer
2014-04-23 19:46                                           ` slush
2014-04-23 19:07                                       ` Tamas Blummer
2014-04-23 19:29                                       ` Pavol Rusnak
2014-04-23 19:44                                         ` Luke-Jr
2014-04-23 19:49                                           ` Pavol Rusnak
2014-04-23 19:55                                             ` Luke-Jr
2014-04-23 19:57                                               ` slush
2014-04-23 20:01                                                 ` Luke-Jr
2014-04-23 20:04                                                   ` Pavol Rusnak
2014-04-23 20:09                                                     ` Luke-Jr
2014-04-23 20:16                                                       ` Pavol Rusnak
2014-04-23 20:32                                                         ` Luke-Jr
2014-04-23 20:35                                                           ` Pavol Rusnak
2014-04-23 20:41                                                             ` Luke-Jr
2014-04-23 20:43                                                               ` Pavol Rusnak
2014-04-23 20:54                                                                 ` Pieter Wuille
2014-04-23 21:06                                                                   ` Pavol Rusnak
2014-04-23 21:18                                                                     ` Luke-Jr
2014-04-23 21:22                                                                       ` Gregory Maxwell
2014-04-23 21:33                                                                         ` Pavol Rusnak
2014-04-23 21:42                                                                           ` Pieter Wuille
2014-04-23 21:44                                                                             ` Pavol Rusnak
2014-04-23 21:48                                                                             ` Gregory Maxwell
2014-04-23 21:53                                                                           ` Luke-Jr
2014-04-23 21:24                                                                       ` Pavol Rusnak
2014-04-23 21:07                                                                   ` slush
2014-04-23 20:59                                                                 ` Luke-Jr
2014-04-23 20:17                                                       ` Tamas Blummer
2014-04-23 20:12                                                     ` Pieter Wuille
2014-04-23 20:08                                                   ` Pieter Wuille
2014-04-23 20:01                                               ` Tamas Blummer
2014-04-23 20:02                                                 ` Luke-Jr
2014-04-23 20:04                                                   ` Tamas Blummer
2014-04-24  6:54                                           ` Thomas Voegtlin
2014-04-24  7:10                                             ` Pieter Wuille
2014-04-24  7:21                                               ` Gregory Maxwell
2014-04-24  8:15                                                 ` Thomas Voegtlin
2014-04-24  7:42                                               ` Thomas Voegtlin
2014-04-24  8:09                                               ` Mike Hearn
2014-04-23 18:48                                   ` Tamas Blummer
2014-04-08 14:49                 ` Andreas Schildbach
2014-04-08 15:46                   ` slush
2014-04-08 15:58                     ` Andreas Schildbach
2014-04-08 16:24                       ` slush
2014-03-27 11:20 ` Thomas Voegtlin
     [not found]   ` <CAJna-HhmFya+3W67qQt0wMhW=B4vJvwdkr-5WnU+KEaKq7uaUA@mail.gmail.com>
2014-03-27 12:06     ` Thomas Voegtlin
2014-03-27 12:28       ` Mike Hearn
2014-03-27 12:49         ` Mike Hearn
2014-03-27 13:12           ` Thomas Kerin
2014-03-27 13:19             ` Mike Hearn
2014-03-27 13:49           ` Thomas Voegtlin
2014-03-27 13:58             ` Jim
2014-03-27 14:20               ` Mike Hearn
2014-03-27 15:17             ` Troy Benjegerdes
2014-03-27 13:07         ` Matias Alejo Garcia
2014-03-27 13:44       ` Pavol Rusnak
2014-03-27 13:53         ` Thomas Voegtlin
2014-03-27 14:03           ` Pavol Rusnak
     [not found]       ` <CAJna-HitjJbL9TnfxTY=+TvfaeNvZM6aPWmNYmHUCwmw6V8PUg@mail.gmail.com>
2014-03-27 15:04         ` Thomas Voegtlin
2014-03-27 11:36 ` Pavol Rusnak

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