From: "Jeremy Spilman" <jeremy@taplink•co>
To: "Gregory Maxwell" <gmaxwell@gmail•com>
Cc: "bitcoin-development@lists•sourceforge.net"
<bitcoin-development@lists•sourceforge.net>
Subject: Re: [Bitcoin-development] unlinakble static address? & spv-privacy (Re: Stealth Addresses)
Date: Mon, 20 Jan 2014 20:00:05 -0800 [thread overview]
Message-ID: <op.w90qqfh4yldrnw@laptop-air> (raw)
In-Reply-To: <CAAS2fgTRKgkO15VUvVgttP-iEBNF4=G+++Xo-XsaRBmOxyXXKA@mail.gmail.com>
On Wed, 15 Jan 2014 17:32:31 -0800, Gregory Maxwell <gmaxwell@gmail•com>
wrote:
> I'd point out that regardless of how long the desired prefix is, the
> encoded prefix should probably always be constant length in all
> reusable addresses.
I might be misunderstanding, but I think prefix length must be specified
in the reusable address, however I agree the prefix actually published to
the blockchain should be constant length.
> If you don't want a particular prefix then the
> sender should just pick random data for the rest of the space. There
> is no need to publish any additional distinguishing data in the form
> of how long the prefix is.
Let's say the payee's reusable address is '<version> <prefix> <Q1> <Q2>
...', where <prefix> is 2 bytes. Without any length indicator. What's the
payer going to put on the blockchain? How would they know what the 'rest
of the space' is? They would have to put the whole <prefix> verbatim into
the OP_RETURN without knowing how many bits of <prefix> the payee actually
wants to see there.
If instead, the address is '<version> <prefix> <prefixLen> <Q1> <Q2> ...'
where <prefix> is 2 bytes, and <prefixLen> is 1 byte, representing number
of bits of prefix that should be fixed.
Then payer will know how much of <prefix> from the address should be taken
verbatim, and the rest of the two bytes would be replaced with random
data, and exactly two bytes would be put in the OP_RETURN.
If <prefixLen> was zero, the 2 byte prefix in the reusable address must be
ignored, and an entirely random 2 byte prefix would be put into the
OP_RETURN.
I'm a bit worried about broken implementations copying the <prefix> from
the reusable address into OP_RETURN when <prefixLen> is 0, and ending up
basically identifying the payee. That's the only reason I can think of to
make '<prefix> <prefixLen>' optional in the reusable address, to prevent
the opportunity to screw it up. You would *still* put a 2-byte random
prefix in the OP_RETURN, even if the fields weren't in the address at all.
It's just a minor concern though.
next prev parent reply other threads:[~2014-01-21 4:07 UTC|newest]
Thread overview: 87+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-01-06 12:03 [Bitcoin-development] Stealth Addresses Peter Todd
2014-01-08 10:20 ` Jeremy Spilman
2014-01-10 10:20 ` Peter Todd
2014-01-10 11:28 ` Drak
2014-01-10 12:00 ` Peter Todd
2014-01-12 10:33 ` Jeremy Spilman
2014-01-12 12:51 ` Mike Hearn
2014-01-12 18:20 ` Jeremy Spilman
2014-01-12 18:26 ` Mike Hearn
2014-01-13 9:13 ` Jeremy Spilman
2014-01-14 14:15 ` Peter Todd
2014-01-14 17:54 ` Odinn Cyberguerrilla
2014-01-12 21:18 ` Gavin Andresen
2014-01-13 9:52 ` Gregory Maxwell
2014-01-13 10:39 ` Mike Hearn
2014-01-13 13:37 ` Roy Badami
2014-01-13 15:58 ` Mike Hearn
2014-01-13 20:11 ` Roy Badami
2014-01-14 22:53 ` Roy Badami
2014-01-15 0:19 ` Drak
2014-01-15 20:22 ` Ben Davenport
2014-01-15 20:38 ` Gregory Maxwell
2014-01-15 20:44 ` Jeff Garzik
2014-01-15 22:38 ` [Bitcoin-development] Static addresses on chains encouraging address *RE* use Troy Benjegerdes
2014-01-15 23:01 ` [Bitcoin-development] Stealth Addresses Mike Hearn
2014-01-15 23:04 ` Roy Badami
2014-01-15 23:07 ` Jeff Garzik
2014-01-15 23:17 ` Roy Badami
2014-01-15 23:19 ` Roy Badami
2014-01-15 23:09 ` [Bitcoin-development] unlinakble static address? & spv-privacy (Re: Stealth Addresses) Adam Back
2014-01-16 1:02 ` Jeremy Spilman
2014-01-16 1:32 ` Gregory Maxwell
2014-01-18 17:44 ` Troy Benjegerdes
2014-01-18 20:25 ` Christophe Biocca
2014-01-20 11:11 ` Peter Todd
2014-01-21 4:00 ` Jeremy Spilman [this message]
2014-01-24 9:17 ` Peter Todd
2014-01-16 11:42 ` Adam Back
2014-01-16 18:19 ` Troy Benjegerdes
2014-01-16 0:05 ` [Bitcoin-development] Stealth Addresses Jeremy Spilman
2014-01-16 0:10 ` Gregory Maxwell
2014-01-16 0:24 ` Mark Friedenbach
2014-01-16 0:44 ` Eric Martindale
2014-01-16 6:26 ` Gary Rowe
2014-01-16 9:48 ` Wladimir
2014-01-16 1:16 ` Odinn Cyberguerrilla
2014-01-16 10:14 ` Drak
2014-01-16 10:19 ` Mike Hearn
2014-01-16 11:12 ` [Bitcoin-development] reusable address privacy problems & fuzzy bait limitations (Re: Stealth Addresses) Adam Back
2014-01-16 21:28 ` [Bitcoin-development] Stealth Addresses Peter Todd
2014-01-17 2:30 ` Johnathan Corgan
2014-01-17 3:13 ` Jeremy Spilman
2014-01-17 7:49 ` Drak
2014-01-17 9:15 ` Mike Hearn
2014-01-17 9:19 ` Mark Friedenbach
2014-01-17 9:23 ` Natanael
2014-01-17 9:59 ` Drak
2014-01-17 20:16 ` Cameron Garnham
2014-01-17 14:46 ` Peter Todd
2014-01-17 19:21 ` Ben Davenport
2014-01-18 4:55 ` Alan Reiner
2014-01-18 5:09 ` Gregory Maxwell
2014-01-18 23:12 ` Jeremy Spilman
2014-01-18 23:50 ` Gregory Maxwell
2014-01-20 11:08 ` Peter Todd
2014-01-13 19:53 ` Roy Badami
2014-01-13 19:57 ` Mike Hearn
2014-01-13 20:01 ` Roy Badami
2014-01-13 19:40 ` Roy Badami
2014-01-13 19:44 ` Drak
2014-01-13 19:59 ` Alan Reiner
2014-01-13 20:10 ` Gregory Maxwell
2014-01-13 20:15 ` Peter Todd
2014-01-13 22:02 ` Jeremy Spilman
2014-01-14 14:19 ` Peter Todd
2014-01-14 19:12 ` Jeremy Spilman
2014-01-14 20:48 ` Peter Todd
2014-01-14 21:51 ` Adam Back
2014-01-14 22:34 ` Jeremy Spilman
2014-01-13 20:14 ` Peter Todd
2014-01-13 20:41 ` Alan Reiner
2014-01-13 20:47 ` Gregory Maxwell
2014-01-13 21:02 ` Roy Badami
2014-01-13 21:15 ` Alan Reiner
2014-01-13 21:27 ` Peter Todd
[not found] ` <op.w9ne31oqyldrnw@laptop-air.hsd1.ca.comcast.net>
2014-01-14 12:10 ` Peter Todd
2014-03-06 12:23 ` Dan Carter
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