The biggest problem of the blockchain at present is the lack of users. Can this kind of new development support at least 10 million new users?

Editor's Note: This article comes fromVernacular Blockchain (ID: hellobtc), Author: Five Fireball Leader, reprinted by Odaily with authorization.

Editor's Note: This article comes from

Vernacular Blockchain (ID: hellobtc)

Vernacular Blockchain (ID: hellobtc)

After the halving of Bitcoin, the Defi trend hit. It can be seen that this year's trend is mainly concentrated on projects that can be implemented and have practical applications, rather than the previous kind of drawing cakes and relying on the market dream rate to support the market value and Fomo emotional rhythm.

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Layer 2, as the most important expansion method before the completion of Ethereum 2.0, finally ushered in the year of landing in 2020. And in the same way, it has also ushered in an era of fighting bayonets, just like 2 years ago, public chains, fighting for TPS, fighting for ecology, fighting to fight... and Layer 2, which will start to land in 2020, are also gearing up and preparing to board It's time for the ring.Layer 2 is an extremely technically oriented category. We will try to give readers a brief introduction to the current major directions of Layer 2 and the various projects represented in the vernacular.secondary title

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As the "oldest" Layer2 technology, channel is the most familiar and famous Layer2. after all,

Bitcoin Lightning Network

No one knows his name, no one knows it.

1. Payment channel representative: Lightning Network

The payment channel is the simplest implementation of channel technology. Friends who are familiar with the Lightning Network are no strangers. In simple terms, both parties to the transaction realize a pledge of a sum of money into the off-chain channel. When necessary, various transfers are made in it. The main amount does not exceed You can use your own balance until the two of you decide to settle, and then go to the chain to settle. It’s a bit like two vendors setting up stalls next to each other. One sells food and the other sells drinks. They order things from each other every day. If they think it’s troublesome to find money every time they pay, they just make a book to keep accounts, and settle at the end of the month. This method avoids the weak TPS on the chain, and theoretically can increase the TPS to a great extent.

However, the payment channel also has many disadvantages. One is that it is only suitable for high-frequency small-amount transactions between two people. If you want to expand, because of the need for pledge, you need some help to transfer, and large accounts with a large balance will inevitably be severely centralized over time. . Furthermore, currently, for these nodes that provide routing (the activity of transmitting information from the source address to the destination address), the incentives for routing fees are too low to cheer up. This has also led to the fact that the Lightning Network has been thunderous and rainy for several years, and has earned a lot of shouting, but it is useless. The general consensus in the industry has also become-BTC will be your digital gold honestly, don’t Thinking about tossing and paying.

2. State channel representatives: Raiden, Celer

The state channel can be regarded as an upgraded version of the payment channel. Like the payment channel, it is a way of "interaction under the chain and liquidation on the chain". It's just the balance of an account, and the update of the status of this account.

While providing the convenience of payment channels, state channels also face the same problems as payment channels, namely a series of security-related issues such as routing, channel balance, node offline, and deposit lock. What’s more embarrassing is that the Lightning Network on Bitcoin has no tokens, and the Raiden Network (Raiden Network), which was the first state channel on Ethereum, was personally criticized by God V, saying that “this technology Is there a need to issue coins?" After all, the Lightning Network is still running without coins, isn't it?IPFSLook, justin Sun's BTFS is about to be launched

side chain

side chain, and there is a new opponent, a peer-to-peer file sharing transmission protocol based on Ethereum state channel technology, and this one does not need to issue coins, just use ETH.

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side chain

side chain

As the name suggests, it is an independent blockchain that hangs on the main chain, "hangs" on the main chain through bridges or relays, and locks assets or states on the main chain at the same time. Because it is an independent chain, the side chain will also have its own consensus algorithm.

1. Representatives of the older generation of sidechains: Loom, Celer

Previously, the popularity of EOS led to the popularity of DPoS. Running a DPoS on the side chain to provide performance, and then running DApp and the like, and then hanging this side chain on ETH, wouldn’t it be a compromise between performance and security?

The idea is indeed very good. LOOM’s technical documentation at that time, including the zombie-interesting Solidity teaching provided, are all commendable things that are second to none in the industry.

Then the reality is very skinny. On the Loom network, no one has ever used it.

Thinking about it now, you may think that it is DPoS anyway, why not develop it directly on EOS or Tron? Why do you have to use an Ethereum DPoS sidechain?

Loom also built the first sidechain that implemented Plasma Cash (Plasma will be called later), but it was useless. After the development team turned to To B and "returned the project to the community", the Loom project can basically be regarded as an announcement Failed.

• By the way, Celer, the main state channel mentioned above, is also doing side chains.

• 2. Representative of the new generation of side chains: Skale

• Skale can be regarded as the main project of the new generation of side chains. The main network has just been launched a few days ago.

The features are as follows:

Elastic side chain: When choosing the size of the chain, the developer can customize the number of resources selected for a single node to provide security for the chain;

Verification node pool: Thousands of independent verification nodes + randomly selected verification nodes of the blockchain + frequent rotation of nodes inside and outside the blockchain;

BLS Rollup: Pay attention to Rollup, which will be mentioned later. Skale uses Rollup technology based on BLS signatures to improve performance by compressing data size through aggregated signatures without sacrificing any security of the main chain at all. Effective support is provided for use cases that require full reliance on primary network custody.

Strictly speaking, Plasma is not considered a sidechain, and should be called a "subchain". However, for convenience, people in the industry usually classify Plasma as a variant of sidechains.

Different from general sidechains that run their own consensus mechanism, Plasma is essentially a blockchain that exists on the blockchain, or "chain-in-chain". The chain's information about the order of transactions is converted into a hash value and stored on the root chain to ensure its security.

The difference from the side chain can be explained in one sentence. Plasma is a side chain with non-custodial features: any error in the Plasma chain can be detected by the user (because the hash value of the sub-chain is stored on the root chain) , and exit the Plasma chain safely, but the problem is to wait for a challenge period, how long? one to two weeks...

Plasma was first proposed by Vitalik and Lightning Network white paper author Joseph. It can be regarded as an ambitious expansion project. However, the process has undergone several twists and turns. The first team to do Plasma was OMG, who was working hard, and the progress was slow. Later, Loom cool of Plasma Cash Cool, Matic was once the only seedling for Plasma. However, just when everyone thought that Plasma was "dead", OMG suddenly went to Coinbase, and Matic's mainnet was launched last month, and Plasma felt revived in an instant.

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Rollup family

The core concept of Rollup is actually a bit similar to Plasma, so many people also regard Rollup as a variant of Plasma, but this variant solves the huge problem of Plasms: data availability.zero-knowledge proofRollup packs a large amount of transaction data originally scattered in the block into a "condensed" transaction, publishes it on the chain, and verifies its security in some form. This verification form is divided into the following types:

1. Representative projects of Zk Rollup: Loopring, Matter Labs

ZK Rollup is a relatively high-end technology, because it uses

zero-knowledge proof

To ensure security, operators must generate a SNARK for each state transition, proving the existence of a series of transactions correctly signed by the owner.

The advantage of ZK Rollup is that it is the safest, and the withdrawal period of funds from the main chain is also the shortest, and it only takes a few minutes if something goes wrong. But there are also disadvantages, that is, because the ZKP technology used is currently relatively high-end and complex, resulting in a long process of generating SNARK proofs, and it also fails to support general-purpose smart contracts, so it is currently concentrated on some applications, such as high-performance DEX, the domestic Loopring DEX is the first ZK Rollup project to come up with a product, TPS2000+, which has received various praises from V God.

Relatively academic Matter Labs (unissued currency) has made some improvements to Zk Rollup, called Zk-Sync, which aims to improve the long-time-consuming generation of SNARK proofs mentioned just now and the difficulty of supporting general-purpose smart contracts. Running the test network, I believe that in the future, we will see further results.

2. Optimistic Rollup representative projects: Idex, Synthetix

Optimistic Rollup removes the high-level zero-knowledge proof in ZK Rollup, and introduces the Plasma penalty mechanism (Otimistic Rollup defaults to "optimistic" and believes that nodes will publish the latest and accurate data to the chain. If someone finds a problem, they can initiate a challenge. , the node will be penalized after success).

The benefits of this are obvious. There is no complex cryptographic zero-knowledge proof. This scheme has higher TPS and better support for general-purpose smart contracts. It is easier to deploy and implement at the current stage. Both Idex2.0 and SNX Optimistic Rollup will be deployed to improve TPS and transaction experience. Of course, everything is a double-edged sword. The consequence is that the security is worse than Zk-Rollup, and there is a 1-7 day exit period, although it is much better than Plasma’s 7-14 days, but Compared with Zk-rollup, it is still too big.

3. Rollup variant: Validium——Representative project: DeversiFi