Cohen’s newest creation, a cryptocurrency known as Chia which bills itself as ‘green money for a digital world’, is the very antithesis of bitcoin. Unlike bitcoin which uses the electricity-guzzling proof-of-work consensus mechanism, the chia cryptocurrency uses proof-of-space where the mining process uses the hard disk space.
Speaking to Breaker magazine Cohen stated that hard disk space is readily and widely available and most of the time unutilized:
The idea is that you’re leveraging this resource of storage capacity, and people already have ludicrous amounts of excess storage on their laptops, and other places, which is just not being utilized. There is so much of that already that it should eventually reach the point where if you were buying new hard drives for the purpose of farming, it would lose you money.
Besides reducing electricity usage, Cohen also claims that Chia cryptocurrency is relatively more secure compared to bitcoin.
According to Cohen who created the BitTorrent protocol in 2001 while still a student at the University of Buffalo, though it would be monstrously expensive to purchase the resources required to attack the bitcoin network, it is possible to do it. For the Chia network, per Cohen, not so easy though:
To attack Chia you’d have to get access to more resources than the network as a whole, which will be a huge amount of resources once everyone has signed up. The cost of acquiring them upfront would be huge, higher than the cost of the ASICs you’d need to attack bitcoin, so to overwhelm the system would be much more difficult.
While the proof-of-space consensus mechanism may appear more secure on paper, it also has its own limitations and this includes the possibility of a re-mining from genesis attack occurring.
With this sort of attack, a bad actor possessing significant network resources creates a new blockchain from the ground up with the goal of switching it for the original blockchain when it gets longer. When executed perfectly the bad actor gets into a position where they can get the new blockchain accepted by the majority of nodes while also taking possession of any number of coins and/or cancelling previous transactions.
To prevent this sort of attack, Cohen has introduced the proof-of-time consensus mechanism. While this does not prevent a bad actor from rewriting years of work, they would require a lot of time to pull it off.
Though it was supposed to be launched towards the end of this year, the world will have to wait a little longer for a ‘greener’ cryptocurrency as the rollout has been pushed forward.