Ethereum's expansion plan: Plasma's past and present (2)

In the previous article, we mentioned the process of the birth of Plasma. In fact, the birth of Plasma was not achieved overnight, but based on another technological improvement, which is the sidechain technology.

The so-called side chain technology is a blockchain attached to another blockchain, and the other blockchain is often called the main chain. In the process of communication between the main chain and the side chain, a trusted third party is required. This third party can be an individual or an alliance composed of multiple individuals.

The communication process between the side chain and the main chain is generally like this. Let’s take Bitcoin as an example:

When a user wishes to transfer a bitcoin from the bitcoin mainnet to its sidechain, the user sends a bitcoin to an address regulated by a trusted third party in the bitcoin network. After the address receives the bitcoin, the trusted third party will notify the sidechain of bitcoin, and release tokens in the sidechain that are equivalent in value to the sidechain of bitcoin.

When the user wants to transfer the tokens on the side face back to the Bitcoin main chain, the tokens on the side chain will be transferred to an address supervised by a third-party organization on the side face. When this address receives the sidechain tokens, the third party will notify the Bitcoin network to release the transferred Bitcoins in the Bitcoin network.

This is how Bitcoin and sidechain tokens are traded back and forth between the Bitcoin mainchain and its sidechains.

Bitcoin has a relatively well-known side chain called Liquid. In this side chain, there is an alliance organization as a trusted third party, and the famous Blockstream company is a member of this alliance.

The side chain technology expands the performance of the blockchain main chain, but it has made certain sacrifices in the trust of the blockchain. During the communication process between the main chain and the side chain, both parties must believe that this trusted third party (whether it is an individual or an alliance) will not do evil.

But isn’t blockchain technology all about trust? Can there be a sidechain technology that does not require the existence of such a third-party trusted organization?

Yes, this is Plasma. Plasma was created to solve the problem of such trusted third parties in sidechains.

In addition to the problem of the trusted third party, there is another problem in the side chain technology: if in the side chain, the trusted third party does not show detailed transaction information but only the message of the block header, so that the miners only Without transaction data, it is impossible to verify the validity of the transaction.

This problem is known as "data unavailability".

And Plasma is also committed to solving this problem, allowing users to transfer funds between the main chain and the side chain smoothly even if the trusted third party does not show detailed transaction information intentionally or unintentionally.

The stated goal of Plasma is so ambitious and sounds so good. Therefore, as soon as it came out in the big bull market of digital currency in 2017, it received high attention from inside and outside the circle. At that time, almost everyone believed that Plasma would solve the congestion problem of Ethereum in one fell swoop, and the performance of Ethereum would skyrocket from then on.

However, with the bursting of the digital currency bubble in 2017 and the advent of the digital currency bear market in 2018, when the enthusiasm for the blockchain gradually receded, people's understanding of Plasma gradually became more objective and rational.

why? Because people found in the process of deploying and using Plasma that although it solved some problems, it brought more problems.