In addition to Lightning Network, is there any other way to achieve blockchain expansion?
From the current point of view, no matter what kind of technical solution is to find a balance between "higher efficiency" and "decentralization", if you want efficiency, you must centralize, and if you want security, you must go centralized. O(1) consensus algorithms currently appearing in everyone's field of vision include off-chain (off-chain channel), sharding (sharding), DAG (directed acyclic graph), multi-chain (multi-chain), etc., each Algorithms have their own characteristics and strengths. This article will explain this type of horizontal expansion solution.
【Off-chain channel】
The concept of off-chain comes from the Bitcoin community. It was proposed in December 2013, and later formed a system of off-chain chains that we are familiar with, that is, side chains. Bitcoin blocks are running all the time, and the amount of money involved in case something goes wrong is too great. This is not allowed. In this case, sidechains were born. Essentially, a sidechain mechanism—a mechanism for moving money between two blockchains—allows assets to be transferred between the Bitcoin blockchain and other chains. Reduce the number of transactions that occur on the core blockchain.
The side chain items for Bitcoin include the recently popular Lightning Network. Its operating mechanism is very simple: suppose A intends to transfer 100 BTC to B, then A must open a payment channel (State channel) with B, and first Mortgage minimum 100BTC. After A mortgages, he can start transferring money to B. A can send B 1BTC today and send B 2BTC tomorrow as he likes, it doesn't matter, anyway, it is an Off-Chain transaction, and no transaction fee is charged at all. The Lightning Network is to provide this kind of payment channel between A and B, that is, Off-Chain (outside the chain) transaction channel.
So, what if A or B wants to withdraw the BTC balance and stop the transfer transaction with the other party? At this point, it is necessary to close the payment channel between A and B, and use a series of protocols of the Lightning Network for liquidation.
A brief summary of how the Lightning Network works:
a. Establish a payment channel;
b. Mortgage is required.
So the application of Lightning Network
a. Frequent exchange of funds;
b. The transaction amount between the two parties is less than the mortgage amount.
For example, the use of Lightning Network between large exchanges is particularly suitable. Funds come and go, and the speed is fast, let alone the transaction fee can save a lot of money. If there are two people who have no connection, if they want to trade, they will inevitably cross several unstable state channels or pass through a large relayer. This relayer may be credible, or may suddenly run away, so In this case, why don't you continue to use Alipay happily? There is another problem with the state channel. The security deposit just mentioned, if you continue to send funds from one party to the other, the security deposit will become less and less, and finally be forced to close, which is also an unstable factor.
Finally, to summarize the current problems of off-chain:
a. The relay is too centralized;
b. Unstable online status;
c. Mortgage asset issues.
【Fragmentation】
Fragmentation, also known as Sharding, first appeared in the database field. At first, all data was placed on one server. Although different users access different data, only one server provides services. Then people think that the easiest way to improve is to put different data on different servers. At this time, accessing different data will be served by different servers, thus breaking through the I/O capability limit of a single-node data server. In short, divide and conquer is the core idea of sharding.
The sharding of Ethereum is simply to divide the blockchain network into several smaller component networks capable of processing transactions, so as to realize a payment system that can process thousands of transactions per second.
Set up a blockchain, there are a hundred different universes in this blockchain system, and each universe is an independent account space. A user can have an account in a certain universe, and the transaction initiated by the user will only affect the transaction-related universe. Is it familiar? Does it sound similar to sidechains? Yes, if the side chain is “grafted externally” to the main chain, then sharding is the “internal division” of the main chain. Obviously, the implementation of the latter is much more difficult than the former! Therefore, many people think that V God has complicated things...even if it is sharding, it will sacrifice a certain degree of "decentralization" for efficiency. By the way, EOS also has shards called Regions.
Sharding is an exciting technology for the blockchain that gives us hope that it can solve the scaling problem with very little impact on decentralization and transparency. However, there is no doubt that sharding technology, especially state sharding, is very difficult at both the design level and the implementation level. This is also the reason why Ethereum has always wanted to go but has not fully followed this path.
【multi-chain】
Multi-chain, that is, abandoning the traditional solution of "one chain governs everything", adopting the new solution of "multi-chain divide and conquer" to redesign a public chain that guarantees the normal operation of each contract. This innovation greatly simplifies the architecture, reduces the pressure of data processing, and ensures that the surge of traffic on one chain will not affect the efficiency of the other chain, and any business carried out on the chain will not receive other business interference, effectively Resource isolation is achieved.
Representative projects of multi-chain include COSMOS, EKT, Polkadot and other projects.
Represented by EKT multi-chain technology, the central idea of EKT is to design a community mechanism so that developers can easily develop a DAPP and leave the rest to EKT. EKT provides a set of underlying blockchain mechanisms, and other blockchain projects can easily deploy their own main chain based on EKT's main chain code. Blockchain projects written on EKT will not need to worry too much about security issues, because each interface is very simple and deployed and run on many parallel main chains. When deploying the main chain, you can flexibly issue tokens of your own main chain and choose a consensus algorithm. The newly deployed main chain can also join the entire ecology of EKT general credits, share the user resources of the EKT ecology, and tokens can also be exchanged and circulated with the EKT main currency and tokens of other main chains.
In EKT, Byzantine Fault Tolerance is implemented using public-private key encryption and routing strategies, and the public key of each node on the EKT main chain is public. This is a solution that balances efficiency, security, and decentralization. Token is now generally defined as a smart contract, but if it is turned into an "object" with pre-defined events, this "object" can have its own parameters (such as total amount, consensus mechanism, etc.), it will bring Better security experience. There are two types of addresses that accept tokens: ordinary user addresses and contract addresses. After receiving tokens, contract addresses can execute non-Turing-complete contract languages for simple state calculations and token transfers. EKT separates the Token chain and the DApp chain, which can largely avoid the fragmentation mentioned above and the difficulties encountered by offchain in the future.
【Directed Acyclic Graph】
DAG is the abbreviation of Directed Acyclic Graph, which is a graph structure with vertices and edges. It is guaranteed to travel along several edges from a vertex (directed), but never return to the origin (acyclic). In the IOTA project, the Tangle mentioned belongs to a data structure of DAG. In a real sense, IOTA does not belong to the "blockchain". You can understand that if Bitcoin and Ethereum use The underlying data structure is BlockChain, while the underlying data structure of IOTA is DAG, but it still belongs to the category of "decentralization".
Directed acyclic graph (Direct Acyclic Graph or DAG) is one of the technical hotspots of blockchain projects in recent years. Many people in the industry believe that this technology may fundamentally solve the problem of blockchain expansion, so related projects are highly popular. However, due to its higher technical threshold and development difficulty, there are still a small number of blockchain projects using this technology, even rarer in China.
On the premise of maintaining good multi-centralization and security, the traditional linear architecture blockchain has a fundamental bottleneck problem in the throughput capacity of the underlying layer. Therefore, the expansion schemes of these blockchain projects, one is to sacrifice the multi-centralized bookkeeping method in exchange for the throughput capacity of the entire chain, and the other is to rely on the second layer (Layer 2) technology such as side chain and sharding to deal with small transactions. To fundamentally obtain better underlying chain efficiency, a completely different architecture needs to be adopted. DAG is a more promising potential challenger. The advantages of DAG over traditional linear blockchains are very obvious, mainly in terms of scalability and transaction throughput.
