The Original Concept: The "Internet of Blockchains" of Ethereum
Originally proposed in 2017 by Vitalik Buterin (creator of Ethereum) and Joseph Poon (co-creator of Lightning Network), Plasma was born as the first major scalability framework for Ethereum. Its design is based on a hierarchy of "child chains" that operate over the main network.
How it works: Imagine a tree where the trunk is Ethereum and the branches are Plasma chains. These process thousands of transactions independently and only send a summary (a hash of the Merkle root) to the main network periodically.
The historical advantage: By not saturating the main chain with every small transaction, Plasma promised to bring Ethereum to processing levels similar to those of Visa.
The challenge: For years, Plasma lost ground to Rollups due to issues with "data availability" and the complexity for users to safely withdraw their funds if the chain operator acted in bad faith.