id	author	title	date	pages	extension	mime	words	sentences	flesch	summary	cache	txt
en-wikipedia-org-1629		Double-spending - Wikipedia			.html	text/html	1284	191	65	Unlike physical cash, a digital token consists of a digital file that can be duplicated or falsified.[1][2] As with counterfeit money, such double-spending leads to inflation by creating a new amount of copied currency that did not previously exist. Prevention of double-spending is usually implemented using an online central trusted third party that can verify whether a token has been spent.[2] This normally represents a single point of failure from both availability and trust viewpoints. By 2007, a number of distributed systems for the prevention of double-spending had been proposed.[3][4] Its cryptographic protocol used a proof-of-work consensus mechanism where transactions are batched into blocks and chained together using a linked list of hash pointers (blockchain). Any pool that achieves 51% hashing power can effectively overturn network transactions, resulting in double spending. ^ The Double Spending Problem and Cryptocurrencies. "Distributed Double Spending Prevention". "Bitcoin Gold hit by 51% attacks, $72K in cryptocurrency double-spent".	./cache/en-wikipedia-org-1629.html	./txt/en-wikipedia-org-1629.txt