Simple understanding of Polkadot
Original title: "Simple Understanding of Polkadot"
Original source: Blue Fox Notes
The public chain is not only the most attractive track in the encryption field, but also the most difficult field to succeed. In addition to Ethereum, which other public chains have opportunities? This is the focus of great attention from both developers and investors. Polkadot is one of the most concerned public chains outside of Ethereum. There are also many introductions about Polkadot. Blue Fox Notes has also mentioned many times before Polkadot's 2019", "Roadmap for Polkadot Network"《Easy to understand Polkadot", "After the launch of Polkadot: the first performance on the line", "Will Polkadot DeFi shake Ethereum DeFi? ", "Polkadot: The cornerstone of the new Internet? ", "Polkad ot) Founder Gavin Wood's Encrypted World", "Cosmos and Polkadot: Blockchain Interoperability". This article is mainly a brief introduction to Polkadot, for beginners to understand Polkadot (Polkadot) services, and more basic articles will be released later.
What is Polkadot
Polkadot is a public chain, but it is A special public chain, which consists of multiple chains, is a public chain that can have multiple chains. Why not use a chain? It tries to solve the problems of scalability, speed, and cost, allowing more personalized blockchains to exist, allowing interoperability and upgrading between chains, and allowing self-governance of chains.
(Source : Polkadot.network)
Polkadot not only supports the transfer of tokens, but also supports the transfer of data between different chains. Its ultimate goal is to become a cross-chain The network protocol makes cross-chain registration and cross-chain calculation possible. Polkadot’s architecture and scalability currently have Bitcoin’s TPS of about 7, while Ethereum’s is about 15, which leads to a very bad transaction experience, slow speed, and high fees, especially during the previous peak mining period. For this reason, Ethereum is gradually moving towards the exploration of Layer 2, especially the practice of the Rollup series. In addition, the sharding of Ethereum is also on the way, although it will take a long time. The picture below is Vitalik’s outlook on the scalability of Ethereum, from 15 TPS to 100,000 TPS.
（Source: Vitalik Buterin）
And Polkadot is taking the road of heterogeneous sharding blockchain. The so-called heterogeneity is actually the "union" of different blockchains. In contrast, Ethereum's shards are isomorphic and are all part of the Ethereum blockchain. In Polkadot, there is a central chain that connects all blockchains, which is the "relay chain". Parachains are connected to the “relay chain”.
< p>(Source: Polkadot.network)
This relay chain + parallel chain architecture is the reason why Polkadot can achieve scalability. Multiple chains can process transactions in parallel instead of on one road Queue for processing. In this way, compared to the current Ethereum, Polkadot can have higher throughput, faster speed and lower fees.
(Source : Polkadot.network)
In the future Polkadot planning, it is even possible to add a relay chain to the relay chain to realize the chain in the chain, trying to pass This approach achieves greater scaling. In addition, the parachains on Polkadot are different from the chains on Cosmos. They have shared security, which is an important reason why developers are attracted to build parachains on Polkadot. Because, for the blockchain, it is not easy to build security from scratch.
The security of the Polkadot parachain
The security of the blockchain comes from whether the consensus is reliable . This is why the consensus mechanism has always been one of the most important components of the blockchain. When the state on the chain changes, all nodes need to reach a consensus, and the mechanism for reaching consensus is the key to whether the blockchain can achieve security.
Poca is a PoS mechanism that mixes BABE and GRANDPA. In the traditional PoW mechanism, people obtain bookkeeping rights through proof of work, while in the PoS mechanism, people need to pledge tokens, and pledgers are also verifiers and stakeholders. They need to verify the state transition proof of the parallel chain. Relay blocks are produced based on the validity of these proofs.
BABE (Blind Assignment for Blockchain Extension) is a block production mechanism running between verification nodes, which determines the generator of new blocks. To some extent, BABE can be compared with Ouroboros Praos, but there are big differences in chain selection rules and slot time adjustment. BABE will allocate slots for producing blocks to verifiers based on the amount of pledged tokens and the Polkadot random cycle.
GRANDPA (GHOST-based Recursive ANcestor Deriving Prefix Agreement) is Polkadot's "finality tool" and serves Polkadot's relay chain. It works fine in a partially synchronous network as long as 2/3 of the nodes are honest and can handle 1/5 of Byzantine nodes in an asynchronous setting. GRANDPA achieves consensus on the chain (compared to the block), which is conducive to its faster finality, even in the face of long-term network partitions or other network failures.
Validators maintain the security of the relay chain by staking DOT tokens, they verify the proofs from Collator, and they also reach consensus with other validators. In order to prevent validators from colluding, validators are randomly selected based on the amount of DOT tokens pledged. If they truthfully report the state change of the assigned parachain, they will be rewarded with DOT; if they are dishonest (checked by other nodes), their pledged tokens will be slashed.
In Polkadot, there is a class of characters called fishermen. They can also report these dishonest verifiers, and fishermen can also be collectors and verifiers. Verifiers will not publish all transactions to Polkadot's relay chain, but only state change proofs. Therefore, the relay chain has no knowledge of the actual transactions on the parachains, but they can verify that the current state is valid. In addition, the verifier will change randomly and will not be fixed on a certain parachain. It is not a part of the parachain, but a part of the relay chain.
(Source : Polkadot.network)
There are also the roles of Nominator and Collator on Polkadot, which are also important roles in participating in the relay chain. Nominator does not directly become a verifier, but can obtain DOT rewards by choosing a verifier to participate in the verification. Of course, if the chosen validators are penalized, they will also be slashed. Collator collects user transactions on parachains and provides state transition proofs for verifiers to maintain parachains. Collator maintains full nodes for the relay chain as well as full nodes for specific parachains.
Interoperation of Polkadot Parachain
At present, it is possible for one chain to dominate the world Sex is not big. Polkadot's cross-chain design has a premise that the future will be a world where multiple chains coexist. Different blockchains are independent, designed differently from each other, and cannot communicate directly. There are interoperability issues between heterogeneous chains. For example, people cannot trade ETH or ERC20 tokens on the Bitcoin chain, nor can BTC directly trade on Ethereum, and cannot directly participate in DeFi on Ethereum. At present, if Bitcoin wants to participate in Ethereum’s DeFi activities, it needs to package BTC first (such as wBTC, etc.).
Parallel chains on Polkadot are interconnected and they can achieve interoperability. The starting point of Polkadot's parallel chain design is that Polkadot believes that blockchains are personalized, and different chains can focus on specific areas. Ultimately each chain serves a different need. For example, some focus on trading, some on lending, some on asset management, some on games, and so on. When these parachains focus on different areas, they may perform better.
In order to facilitate developers to build parallel chains, Polkadot provides a framework for building blockchains, Substrate, which supports developers to start and run their own chains in a short time. defined blockchain. Substrate also supports developers to build blockchains in a way similar to building Lego bricks according to their own needs. The blockchain built through Substrate can not only interoperate with other parachains on Polkadot, but also connect with other blockchains (such as Ethereum) through token bridges.
The upgrade and governance of Polkadot
The upgrade and governance of the blockchain has always been a big problem question. This is also related to the fact that the blockchain is a decentralized network. Hard forks have also become a common sight in blockchains when upgrades are not well resolved by governance. In order to iterate, project developers and node operators need to do a lot of work.
However, the parachain on Polkadot does not need to worry about hard forks. Polkadot solves this problem through the governance system and code level. Polkadot's code is updated according to its voting system, which is also part of the blockchain itself. The Polkadot network updates the core code, publishing transactions similar to deploying smart contracts. As a result, iterative updates can be achieved without hard forks, and nodes do not need to do more operations.
Of course, this also means that the holders of the Polkadot token DOT are very important, and it is the DOT holders who determine the future direction of Polkadot.
In Polkadot governance, it includes DOT holders, councils and technical committees who actively participate in governance. When the number of votes for a proposal passes a specific voting indicator, the proposal will be passed.
Proposals are generally proposed by ordinary token holders or councils, and will ultimately be decided by the vote of DOT token holders. In the common token holder's proposal, users only need to deposit the minimum required amount of tokens within a certain period of time to initiate a proposal. And if other people agree to the proposal, then they will deposit the same amount of DOT to support it. The proposal backed by the largest amount of DOT tokens is selected as the unanimous voting proposal. As for the council proposal, when all council members agree, it will become a general voting proposal. It adopts an adaptive quorum approval mechanism. The smaller the number of pledged votes, the smaller the number required for its approval. If it is a proposal approved by a majority of council members, it can also become a plenary vote proposal, but its threshold is higher, and it requires a majority of votes to pass a resolution.
(Source : Polkadot.network)
The council is of great significance in the governance of Polkadot, which is different from the pure community governance of DeFi. In Polkadot's council, which consists of 13 to 24 members, the council has some relatively special rights: conduct general votes and emergency votes; cancel controversial or malicious general votes; elect technical committees; There is more weight in voting.
Polca Token Economic Mechanism
DOT is the native token of the Polkadot network, as ETH is the same as the native token of Ethereum, and its smallest unit is Planck, which is similar to Wei on Ethereum.
The main uses of DOT are:
*DOT serves network governance
Holding DOT has the opportunity to obtain voting rights for proposals, and can participate in the resolution of proposals, such as determining network fees, adding or removing parachains, etc.
*DOT serves network security
DOT also serves the consensus mechanism supporting the Polkadot network. To achieve consensus, participants need to stake DOT tokens. This is the most important role of DOT, which is responsible for the security of the Polkadot network.
*DOT service parachain
In order to become a parachain of the Polkadot network, a certain amount of DOT must be bound for a period of time . During the binding period, DOT will be continuously locked. This means that if the Polkadot ecology is favored by developers, DOT will become popular in order to compete for limited positions.
From the above mechanism, DOT’s token mechanism is deeply bound to its Polkadot network, and is deeply integrated with its governance, security and usage . If the Polkadot ecology develops, its governance, security, and usage will create a great demand for DOT. In other words, the value of DOT itself is highly related to the Polkadot ecological development itself.
Some public chains may develop well, but their tokens do not necessarily capture the value proportional to their ecological development. From this perspective, DOT's token design mechanism is conducive to the capture of its future value.
Polkadot’s road to public chain
From a paradigm perspective, Polkadot is still a smart contract The scope of the platform. Where will it go under the ecology of Ethereum? Is it beyond Ethereum? Or is it an important addition to Ethereum?
It depends on the evolution of the developers, the community and the public chain itself. Can Layer 2 and sharding of Ethereum play an important role in the future, and how to achieve interoperability between Layer 2 and shards? Is Ethereum's road to scalability smooth? Is Polkadot's cross-chain model a better path, and can it win the favor of developers? Do other public chains like Solana have a chance of gaining ground?
There is no clear answer to these, but one thing is certain, the public chain is the most important infrastructure in the encryption field, and the evolution of the public chain in the future will directly determine the entire Where the crypto space is headed.
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