BIP: xxxx

Title: Dust Consolidation Transactions

Author: Chris Charabaruk <chris+NOSPAM@charabaruk.com>

Status: Draft

Type: Standards Track

Created: 17-07-2013

Abstract

========

This BIP proposes adding support for fee-free consolidation transactions for

merging dusts into non-dust coins.

Motivation

==========

Current requirements for fee-free transactions make it hard, if not impossible,

for users to send transactions that include small inputs. The purpose of dust

consolidation is to allow users to avoid high transaction fees caused by a

large amount of dust inputs when sending Bitcoin payments.

Specification

=============

Dust Consolidation Transaction Qualifications

---------------------------------------------

A transaction will be considered a Dust Consolidation Transaction (DCT) when it

meets the following requirements:

* It has two to five inputs, where a majority of the inputs must be

individually below the dust threshold.

* It has one and only one output.

* Its priority is equal or greater to that of a one day old dust threshold

coin in a 250 byte transaction.

Any transaction meeting these requirements may be sent without a fee, allowing

a user with a surplus of dust to consolidate them into more useful coins for

later spending.

Block Inclusion

---------------

When adding transactions to a block from the miner's memory pool, priority

should be given for DCTs over other transactions, to a limit of ten (10) such

transactions. This ensures that DCTs will be mined into blocks, while also

limiting the risk of penny-flooding attacks on the network.

DCTs should be ordered by age of the newest input in transactions rather than

by transaction priority when they are being mined.

Sending and Relaying

--------------------

DCT rules should be added to clients for sending fee-free transactions. DCTs