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Date: Fri, 5 Jun 2015 20:12:08 -0400
Message-ID: <CAGH37SK0k1YUvadetyHcBGjzW+OHNFRmRwqsUDeHBGejUacigQ@mail.gmail.com>
From: Kristov Atlas <kristovatlas.lists@gmail.com>
To: Bitcoin development mailing list
	<bitcoin-development@lists.sourceforge.net>
Content-Type: multipart/alternative; boundary=089e0160b7d4680a9e0517ce4231
Subject: [Bitcoin-development] Lexicographical Indexing of Transaction
	Inputs and Outputs
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Hello all,

I have written a draft of a BIP to standardize the sorting of tx inputs and
outputs for privacy and security reasons. A few colleagues have reviewed
this and provided feedback privately, but now it's ready for feedback from
a wider audience.

If there is positive sentiment about the proposal after feedback is
integrated, I aim for a bip number to be assigned and have it accepted into
https://github.com/bitcoin/bips

Link:
https://github.com/kristovatlas/rfc/blob/master/bips/bip-li01.mediawiki

For your convenience, here's the abstract:

"Currently there is no standard for bitcoin wallet clients when ordering
transaction inputs and outputs. As a result, wallet clients often have a
discernible blockchain fingerprint, and can leak private information about
their users. By contrast, a standard for non-deterministic sorting could be
difficult to audit. This document proposes deterministic lexicographical
sorting, using hashes of previous transactions and output indices to sort
transaction inputs, as well as value and locking scripts to sort
transaction outputs."

Thanks,

Kristov Atlas
Open Bitcoin Privacy Project Contributor, Blockchain.info Security
Engineer, etc.
Twitter: @kristovatlas
Blog: kristovatlas.com

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<div dir=3D"ltr"><div><div><div><div><div><div><div><div>Hello all,<br><br>=
</div>I have written a draft of a BIP to standardize the sorting of tx inpu=
ts and outputs for privacy and security reasons. A few colleagues have revi=
ewed this and provided feedback privately, but now it&#39;s ready for feedb=
ack from a wider audience.<br><br></div>If there is positive sentiment abou=
t the proposal after feedback is integrated, I aim for a bip number to be a=
ssigned and have it accepted into <a href=3D"https://github.com/bitcoin/bip=
s">https://github.com/bitcoin/bips</a> <br><br>Link: <a href=3D"https://git=
hub.com/kristovatlas/rfc/blob/master/bips/bip-li01.mediawiki">https://githu=
b.com/kristovatlas/rfc/blob/master/bips/bip-li01.mediawiki</a><br><br></div=
>For your convenience, here&#39;s the abstract:<br><br>&quot;Currently ther=
e is no standard for bitcoin wallet clients when ordering transaction input=
s and outputs. As a result, wallet clients often have a discernible blockch=
ain fingerprint, and can leak private information about their users. By con=
trast, a standard for non-deterministic sorting could be difficult to audit=
. This document proposes deterministic lexicographical sorting, using hashe=
s of previous transactions and output indices to sort transaction inputs, a=
s well as value and locking scripts to sort transaction outputs.&quot;<br><=
br></div>Thanks,<br><br></div>Kristov Atlas<br></div>Open Bitcoin Privacy P=
roject Contributor, Blockchain.info Security Engineer, etc.<br></div>Twitte=
r: @kristovatlas<br></div>Blog: <a href=3D"http://kristovatlas.com">kristov=
atlas.com</a><br></div>

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