Plasma Review: Child-chains and ETH Father-chain

If you are a biology student, the term "Epiphytes" should not be strange to you. For those trying to get a date for the dance or to whom biology class is tantamount to nap time: Epiphytes are plants that thrive on preexisting plants. They usually depend on these host plants for their nutrients amongst other things. Well, now you have learned something new (if you haven't already known this) that will serve as the perfect introduction to the wonderful project we are about to discuss in this article. 

Plasma is ..

Plasma is a series of contracts operating on a blockchain which is already in existence, ensuring the enforcement, at the same time, making sure funds can be held by individuals in a contracted state, with net withdrawal or settlement at a later date. Are you thinking what I am thinking? Yes! Plasma and Epiphytes? I mean that was too obvious, right? 

Anyways currently Smart contracts on the Ethereum blockchain are being executed on the main network, the development of plasma makes it possible for Smart contracts to be executed off-chain (Ethereum main Network). As a result of this, it becomes possible to experience an incredible speed of up to 1 billion transactions per seconds. 

Plasma makes it possible for Scalable computation on the Ethereum blockchain with the structure of creating economic incentives to persistently and autonomously operate the blockchain without the contract creator having an active state transition management. Therefore to operate the chain, the nodes themselves are incentivized.

Significant scalability is easily achieved with a Plasma chain by making sure that funds represented in a spend, going from a contract to a singular bit located in a bitmap, is greatly minimized. This is so that a single signature and transaction stands for a payment connected with several participants. These factors are then combined with a MapReduce framework which in turn makes it possible for a scalable computation which bonded smart contracts enforces to be constructed.

An individual can, therefore, have externalized parties hold funds with this construction, as well as compute contracts on an individual’s behalf similar to a miner. It should be noted that Plasma runs on top of a blockchain that is already in existence in order to prevent an individual from having to create transactions for every state on the underlying chain, which includes adding some new network participants’ ledger entries, with reduced data on-chain for connected state updates.  

Plasma: Scalable Autonomous Smart Contracts 

A method was proposed to scale to process by decentralized autonomous applications, not just financial activities, but construct economic incentives also, which are meant for globally persistent data services, with the possibility of producing an alternative to centralized server farms.

Having all blockchain computation reframed into a set of MapReduce functions, is one of the two key parts of the Plasma structure. Another part of the design plasma entails is employing a Proof-of-Stake token bonding on top of existing blockchains.

Composing smart contracts is used to achieve this construction on the main blockchain using fraud proofs. With this on the parent blockchain, state transitions can be enforced. Blockchains are composed into a hierarchy, in a tree pattern, and every single individual branch blockchain is treated with enforced blockchain history, as well as MapReducable computation committed into Merkle proofs. Going by this, using a child blockchain enforced by the parent chain, by framing one's ledger entry, incredible scaling with minimized trust can be enabled. Through creating mechanisms which will incentivize and enforce the execution of data continually and correctly, as well as allowing for exiting faulty chains, Plasma is able to provide mitigations for the issue of data availability and block withdrawal attacks, where the greatest complexity around global enforcement of non-global data revolves around.

For example, Ethereum, being a root blockchain where only merkleized commitments are broadcast periodically to during non-faulty states, incredibly scalable, low-cost transactions and computation can, therefore, be allowed. Also, persistently operating decentralized applications is enabled by Plasma, at an incredible high scale. 

Scalable Multi-Party Computation 

The solution for ensuring correctness with blockchains has been for all network user to generally validate the blockchains by themselves. In this manner, a full validation of the block is needed to accept a new block, to check its correctness. 

The use of time commitments to build a fidelity bond is required for any efforts to scale blockchain transactional capacity, in order for the asserted data to compulsorily become the subject to a dispute period for entirely all participants on the blockchain to enforce the state.

This assert construction gives room for an individual to check and confirm that a particular state is correct. This also allows an individual to assert if the value is incorrect, after which, a dispute period exists. During this dispute period, another observer can challenge these assertions, by simply providing a proof, before a certain agreed time.


In case there is an occurrence of a faulty or fraudulent behavior, the faulty actor can now be penalized by the blockchain. In order to be encouraged to enforce if there is an assertion of the incorrect state, a mechanism for all participants is created. With the possession or access of this assert or challenge-proof construction, participants that are interested can then be able to assert ground truths to participants that are not interested in the root blockchain.

Although payment is what this structure can only be used for, it can, however, be extended to computation itself. The purpose of this is to make the blockchain the adjudication layer for contracts. This presumption would, however, mean that every single party becomes a participant when it comes to validating the computation. The construction in Lightning Network, for example, makes it so that commitments to computing contract state can be established by an individual.

These constructions permit at scale, highly powerful computation, although the summation of numerous external states such as; the summation of entire markets or systems, large number of contributors, computation of a large amount of shared/incomplete data, etc, are required for some issues 

Also, the presumption of ”rounds” is usually present, whereby before contract begins, the execution path must be completely unrolled. This provides the opportunity for participants to exit and force expensive computation on-chain because it is impossible to prove the halting party.

A plan to design a system that allows computation off-blockchain that is absolutely enforcible on-chain, and is scalable to billions of computations in a second, with minimal on-chain updates is already in process. Across an autonomous set of proof-of-state validators, incentivized towards correct behavior enforced by fraud proofs, is where this state update happen, making room for computation to exist without any actor having the power to halt the computation service easily. 

Components of the Plasma Network 

There are five important components which make up the Plasma network:

1. Child chains are arranged in a tree format which aids in capitalizing on low-cost efficiency and overall settlement of a transaction.

2.  An incentive layer made available for the consecutive computation of contracts in an economically efficient manner. 

3. A MapReduce computing framework which is designed for the construction of fraud proofs of state transition which are located within the available nested chains which are in turn made to be highly compatible with the tree structure while still reframing the state transitions to be highly scalable,

4. A consensus mechanism which attempts to duplicate the result gotten from the Nakamoto Consensus incentives and is quite dependent upon the root blockchain.

5. A bitmap-UTXO commitment structure which is there, for ensuring that a valid state transition of the root blockchain while mass-exist cost is being minimized.

Joshua Dylan