SIP: 0004
LAYER: Consensus
TITLE: DOUBLE SPEND PREVENTION
AUTHOR: Derek Ross (twitter.com/derekmross)
STATUS: Active
TYPE: Standards Track
CREATED: 2022-7-20

ABSTRACT

At times, the Stackchain can get very busy with a multitude of transactions coming through. These can be regular full stacks or partial Stackjoins. When the network gets congested, we run the risk of double spending. This SIP aims to stop double spending from happening.

PROCESS

	1) Any purchase that's 3 hours older than the originating Tweet will be rejected unless proof is provided that it was orphaned or published by another pleb.
	2) Screenshots or pictures with date and time visible are strongly recommended when the app does not provide a date or time.
	3) Stackjoins do not have a time limit on purchases.
		a) Nodes should still verify the timestamps for stackjoin posts.
		b) This rule cannot be used to evade rule #1 with intent to prebuy.