Subject: [Bitcoin-development] Lexicographical Indexing of Transaction Inputs and Outputs

From: Kristov Atlas <[email-masked]>
Date: Fri, 5 Jun 2015 20:12:08 -0400

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