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From: Peter Todd <pete@petertodd.org>
To: Mike Hearn <mike@plan99.net>
Cc: Bitcoin Dev <bitcoin-development@lists.sourceforge.net>
Subject: Re: [Bitcoin-development] BIP 70 refund field
Date: Mon, 31 Mar 2014 11:23:09 +0200	[thread overview]
Message-ID: <20140331092309.GA19482@tilt> (raw)
In-Reply-To: <CANEZrP0AwR3WgHfwYWcrC9Z_MHPDwymWXAQwp7D8XZ+o2FsK8g@mail.gmail.com>

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On Fri, Mar 28, 2014 at 12:07:04PM +0100, Mike Hearn wrote:
> Though I am loathe to go back and redesign this part of BIP 70 so soon
> after we shipped v1, it seems to me like the refund feature may be hard to
> implement on phones if there's no time limit for when you can receive a
> refund. Otherwise a wallet has to be looking out for refunds for payments
> you may have made years ago. So perhaps we should add a new refund field
> that embeds a PaymentDetails structure instead of being just a list of
> outputs.
> 
> We could try and solve this problem some other way purely internally, by
> doing a kind of wallet-specific swapping process in which things like Bloom
> filters are calculated without all keys in them being held in memory at
> once (perhaps caching filters for old parts of the key chain on disk), so
> you can have "infinite" wallets, but eventually the huge Bloom filters that
> would result would hurt efficiency in other ways. So key expiry seems
> pretty fundamental to scalability.

One of the main goals of steath addresses is actually scalability. In
particular in the refund address case you would use stealth addresses
with a per-order UUID so that refunds can be detected cheaply by just
scanning for payments to your (single) stealth address, then when those
payments are detected, check the UUID against a on-disk database. A
64-bit "UUID" is probably fine, although unfortunately with OP_RETURN
quite unexpectedly dropped to 40 bytes the standard needs to change;
might have to compromise on privacy and re-use a txin pubkey to make
things fit.

-- 
'peter'[:-1]@petertodd.org
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      parent reply	other threads:[~2014-03-31  9:23 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-03-28 11:07 [Bitcoin-development] BIP 70 refund field Mike Hearn
2014-03-28 11:25 ` Andreas Schildbach
2014-03-28 11:31   ` Mike Hearn
2014-03-28 16:59     ` Andreas Schildbach
2014-03-28 18:19       ` Mike Hearn
2014-03-28 20:56         ` Andreas Schildbach
2014-03-29  9:27           ` Roy Badami
2014-03-29 13:29             ` Mike Hearn
2014-03-30 17:21               ` Andreas Schildbach
2014-03-28 11:38   ` Wladimir
2014-03-28 11:45     ` Tamas Blummer
2014-03-28 11:46       ` Mike Hearn
2014-03-28 11:54         ` Tamas Blummer
2014-03-28 12:27           ` Mike Hearn
2014-03-28 12:55             ` Tamas Blummer
2014-03-28 13:00               ` Mike Hearn
2014-03-28 13:09                 ` Tamas Blummer
2014-03-28 11:30 ` Tamas Blummer
2014-03-28 13:18   ` Tamas Blummer
2014-03-28 14:01     ` Gavin Andresen
2014-03-28 14:06       ` Mike Hearn
2014-03-28 14:27       ` Tamas Blummer
2014-03-28 15:23         ` Mike Hearn
2014-03-28 15:26           ` Tamas Blummer
2014-03-28 16:34             ` Mike Hearn
2014-03-28 16:45               ` Tamas Blummer
2014-03-31  9:23 ` Peter Todd [this message]

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