Plasma

Basics

• Created by OmiseGo in 2017
• The Plasma paper was published by Vitalik Buterin and Joseph Poon on 11-8-2017.
• From this blog by PlotX (25-1-2021):

"It’s a framework for building scalable applications on Ethereum that leverages the use of smart contracts and Merkle trees to enable the creation of an unlimited number of child chains which are copies of the parent Ethereum chain."

• From this (25-8-2018) reddit thread:

"The concept of Plasma is to have another chain attach itself (as a "child chain") to Ethereum (the "parent chain") to contribute computing power. Ethereum maintains complete control of the system and determines what the true state of the system is. I like to think of it like this:

You want to use your friends computer to help speed up your own computer, but not let your friends computer have any control. It simply contributes processing power. So certain calculations you decide to send to the friends computer, and it computes it fast, but ultimately your own computer decides if it likes the calculation your friends computer completed. That is like Plasma.

For instance Omisego (the company heading Plasma research), will contribute their chain to be a child chain to Ethereum. Ethereum can then off-load some of it's transactions to the OMG chain. Then the OMG can do all the important stuff, and return the final state of everything after all of it's transactions to the Ethereum network. At the end of the day everything is set-up in such a way that Ethereum maintains complete control.

Plasma Cash:  is like the bitcoin lightning network, but it limited to payments with non-fungible tokens (like exchanging physical coins). A competing method is "Plasma MVP". The basic concept is the same though."

• From this (25-5-2018) reddit comment:

"Plasma Debit is the same as Plasma Cash, but allows for arbitrarily-sized payments between different Ethereum addresses (like a debit card). For more here.

At present, they all run on a PoA network with a single node called an 'operator' - this is a highly centralized model and teams are looking to transition this to PoS."

History

• As of 1-2020 Plasma has seemed to cease to exist (27-1-2020 done by Dragonfly). Plasma Group has converted to Optimism. Reasons for this are explained in the above link and come down to Plasma creating more problems than solutions. Zk-Rollup and Merged Consensus both came out of plasma like technology.
• There used to be a Leap Plasma Chain, but the team behind it, LeapDAO, shut it down (20-2-2020) and started focusing on Zk-Rollup.

Compared to other scaling options

• From this blog by PlotX (25-1-2021):

"Offloading transactions from the main chain to a child chain allows for fast and cheap transactions. But, on the other hand, one drawback is that users have to wait several days before they’re able to withdraw their funds from the child chains. Moreover, just like Channels, Plasma also doesn’t support general-purpose smart contracts execution."

• From Daily Gwei (25-9-2020):

"The main difference between Plasma and Optimistic Rollups (OR’s) is that OR’s can run virtual machines - so-called Optimistic Virtual Machines (OVMs) - which allows for the execution of smart contracts on layer 2."

Funding

• Done by OmiseGo, Gitcoin, Matic, Status and Ethereum Foundation (still as of 1-2020)

Collaborators & Contributors

• According to this blog (1-2020):

Uniswap, Whiteblock, Abbey Titcomb, Alex Attar, Cryptoeconomics Lab, Dan Robinson, Eva Beylin, Georgios Konstantopoulos, Mikerah Quintyne Collins