The overall structure and process of Wanchain Galaxy Consensus Exploration

Galaxy Consensus ( click to view: full text of the Yellow Book ) is a new, efficient, scientific and safe PoS consensus protocol proposed by the Wanwei Chain Theory R&D team to replace the original high energy consumption PPoW (permission proof-of-work) ), also officially open the consensus system of Wanwei Chain to the community, and take a crucial step towards complete decentralization. Under the current situation of many blockchain systems, safe and efficient consensus protocols have become one of the main research directions. Many consensus models such as PoS, PoA, PoI, etc. have been proposed one after another, and in many consensus models, they have been cautious. Thinking, Wanwei Chain believes that rights are the fundamental factors in the governance and development of the left and right chains. It also developed the PoS galaxies consensus agreement, and built a consensus galaxies belonging to the Wanwei chain under the operation of the consensus nodes of the stars.

First, the overall frame design

For the design of the consensus agreement, the two main problems are solved: the leader selection and the legal chain selection. In the traditional PoW, the choice of the blocker is carried out by mining. With the randomness of the hash function, the miner relies on his own computing power to participate in the competition of the blocker, and the fairness here is reflected in any node. For the unpredictability of the hash function results, any node has no advantage, and can only solve the problem through simple and ruthless exhaustive operations. The choice of the legal chain is often the rule that takes the longest chain, that is, the branch with the most computing power becomes the mainstream. Such a framework of mining and the longest chain rule leads to a large amount of energy waste, and is one of the root causes of other consensus agreements. So what is the current mainstream PoS protocol to solve this problem through the framework design?

After a long period of research and study, we briefly introduced the mainstream framework of the PoS consensus with three well-known consensus protocols:

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Cardano 's Ouroboros is the leading academic paper published at the Smithsonian Conference and the first provable secure PoS algorithm adopted by industry. Its outstanding contribution is to propose and prove a secure consensus model framework. Practical algorithm module. In its multiple series, there are different ways to choose the blocker. From the initial selection of the random number to the anonymous selection using the VRF algorithm, Ouroboros gradually secures the selected process privacy, while the effective chain The choice is always the longest chain rule, which is the chain based method, which guarantees the security of the chain. So the overall framework of Ouroboros is the VRF selection + Chain based mode.

Algorand is a PoS Consensus Agreement proposed by Turing Award winner and Professor MIT Sivio Micali. Its outstanding contribution is to design the BFT upgrade agreement BA* protocol, which uses voting to solve the choice of block legitimacy. The certifier's choice on Algorand also uses the VRF algorithm to ensure randomness and anonymity. After the operation of the BA* protocol, every block of height is guaranteed, even if it is empty, it is voted. Certified. So Algorand's overall framework is the VRF + BA* voting mode.

Casper is a PoS consensus protocol currently developed by Ethereum. With its practicality, Casper adopts a betting-style consensus. The verifier who completes the margin pledge can bet on the block that he believes will be confirmed, and is guaranteed by the betting rules. The uniqueness of the final winning block, and the winning verifier will also benefit. Casper will help Ethereum transform from PoW to PoS, and is a consensus agreement that everyone is looking forward to. So Casper's overall framework is the mode of verifier + betting.

After a brief introduction to several mainstream PoS consensus protocols, we returned to the galaxy consensus. After in-depth thinking and research, the galaxy consensus adheres to the development path of the academic school, drawing on the model framework that Ouroboros can prove safe, and the new design of more efficient and safe random numbers. The algorithm is generated, and the Unique Leader Selection algorithm is innovatively designed to replace the VRF algorithm for the choice of the blocker, which ensures the uniqueness of the legal blocker and greatly reduces the natural fork probability. Therefore, the overall framework of the galaxy consensus is ULS + Chain. Based on the premise of ensuring security, the utility is greatly improved.

Second, two kinds of stars

In the galaxy consensus, all users who pledge the WAN in smart contracts will become a node in the entire galaxy, and these nodes are divided into two kinds of stars due to their ability: star and planet.

In order to distinguish between two kinds of stars, we have to say the delegation mechanism in the galaxy consensus. In order to provide a consensus for users who only hold a small number of WANs or less interests, we have designed a complete delegation mechanism in the galaxy consensus. The implementation of the delegation mechanism is based on the triple ECDSA delegation signature algorithm, which has natural compatibility with the current blockchain system. Through the delegation mechanism, users holding a small number of WANs can entrust their own rights to the agent nodes, and the agent nodes participate in the consensus. At the same time, due to the limitation of the signature message space, the proxy node can only make a block and cannot perform other operations, which ensures the security of the user's rights and interests.

Knowing the delegation mechanism, you can introduce the difference between the two stars. In the galaxy consensus, the stellar node is a consensus node that can accept the entrustment, and it holds a certain amount of equity, and its own equity value will affect the upper limit of the equity it accepts; the planetary node is a consensus node that cannot accept the entrustment. Participation in consensus is entirely dependent on the value of equity held by itself. Although the size of the two stars is different, it is the same in the process of participating in the consensus and does not make a distinction. How to become a stellar node requires more equity pledge on the one hand, and depends on the degree of credibility of the node on the other hand. The final method will be described in detail later.

Three, two types of constellations

In the galaxy consensus, the participating nodes are divided into two constellations due to the division of tasks: the RNP constellation and the EL constellation, which mainly solve two key problems in the consensus.

The RNP constellation is selected according to the proportion of its own equity in all galaxies' consensus nodes, and is responsible for constructing the population of random numbers on the chain. The nodes in the RNP constellation complete the random number update through the three stages of DKG1, DKG2, and SIGN, ensuring the security of the random number on the chain. As stated in the mainstream PoS framework described above, how to maintain a fair random number is the top priority of the security of the protocol. The RNP constellation is responsible for this critical work, and the random number generated in each round will be used as The important seeds of star group construction, blocker selection and other random source applications maintain a healthy operation of consensus.

The EL constellation is selected according to the proportion of its own equity in all galaxy consensus nodes, and is responsible for collecting transactions and packing out groups. The EL constellation needs to complete two cycles of work. The first cycle completes the secret message array negotiation through two stages of SMA1 and SMA2, and completes the sharing of secret data inside the EL constellation. The second cycle passes the secret. The information sequence and the random number on the chain determine the block right attribution, and package the block and broadcast in the time period in which it is responsible for the block out, complete the growth and development of the chain, and its role is undoubtedly the basis for ensuring the safe operation of the consensus.

Fourth, the operation process

After introducing two kinds of stars and two types of constellations, we describe the running process of the galaxy consensus from a higher perspective and give you an intuitive display. First we introduce two concepts of time: slot and epoch. I believe that the readers who know about Ouroboros should be familiar with these two concepts. The slot is the generation time of a block, that is, a new block is generated in each slot, and the epoch is a time period composed of a large number of consecutive slots. A loop in which the protocol runs completely. The following four steps describe the protocol running process:

1. Building a galaxy

This is the preparation phase of the protocol operation. At this stage, all nodes that want to participate in the galaxy consensus will pledge a certain amount of WAN into a galaxy node in the consensus smart contract, and the lock time will be selected when pledging. This time will affect the node's The equity value, the longer the lock-in time, the correspondingly higher equity value, and the equity value will also increase with the lock-up time. This design simulates the concept of currency age and ensures the rationality of equity design. And the fairness of node participation. After this stage of preparation, a large number of nodes appear in the galaxy, and these nodes will officially run the galaxy consensus.

2. Forming a constellation

At the beginning of each protocol run cycle (epoch), two large constellations, the RNP constellation and the EL constellation, are selected in the galaxy. The choice of these two constellations is based on the proportion of the node holding equity value. The random selection process performed by random numbers on the chain is similar to follow-the-satoshi. Here we use follow-the-stake-ratio to ensure the fairness of the galaxy nodes participating in the formation of the constellation. The higher the proportion of equity, the selected The greater the probability of a constellation, the greater the possibility of participating in consensus and gaining revenue, which is one of the core ideas of the PoS consensus.

3. RNP constellation operation

After the RNP constellation is selected, the nodes in the constellation complete the three phases of DKG1, DKG2 and SIGN. In the DKG1 phase, each node proposes its own commitment to random number fragment selection, ensuring the unchangeableness of the fragment selection. In the DKG2 phase, each node shares the random number fragments selected by itself into other nodes in the constellation through secret sharing. Finally, in the SIGN phase, each node publishes the random number fragment data collected by itself and completes the generation of random numbers. Update the random number data on the chain. The whole process is guaranteed by the secret sharing of the threshold, as long as the number of online nodes exceeds the threshold, the random number update will be completed smoothly, ensuring the reliability of random number generation, and at least one node in the constellation is in the random number fragment. The choice is random, then the final random number result is random, ensuring the security of random number generation.

4.EL constellation operation

After the EL star group is selected, it will participate in two cycles (epoch) work. In the first cycle, the EL constellation node participates in the two phases of SMA1 and SMA2. In the SMA1 phase, each node proposes the commitment data of its own secret information, which guarantees the unchangeableness of the secret information. In the SMA2 phase, each node will The secret information of oneself is encrypted and shared with other nodes to complete the generation of a secret message array. At the beginning of the second period, the nodes in the EL cluster are sorted according to the random number generated by the RNP constellation. This sorting is valid throughout the period, and the block selector algorithm is executed according to the secret information sequence to determine the whole. The block right of each time slot in the cycle belongs to the process. This process is secretly executed within the EL star group. Other nodes cannot know the result, and the nodes in the EL star group complete the whole cycle according to the ownership of the block weight. The generation of new blocks, when the new block is proposed, the nodes in the EL star group should add their own legality credentials, which can be verified by the whole network, ensuring the normal and safe development of the chain.

The above briefly introduces the overall framework and operational process of the galaxy consensus. The details are described in the galaxy consensus paper. In the subsequent galaxy consensus exploration, we will further introduce the design ideas and operation processes of each module component. Gradually present the complete blueprint for the galaxy consensus system, so stay tuned.

For consensus node business cooperation, please contact [email protected]

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Related background knowledge added:  

1. What is Cardano's Ouroboros consensus algorithm?

Https://www.cardano.org/en/ouroboros-3/

2. What is a verifiable random function (VRF)?

https://en.wikipedia.org/wiki/Verifiable_random_function

3. What is the Algorand Consensus Agreement?

Https://www.jianshu.com/p/c1f73f2eafac

4. What is the Casper Consensus Agreement?

Https://arxiv.org/pdf/1710.09437.pdf

5. What is the Elliptic Curve Digital Signature Algorithm (ECDSA)?

Https://www.jianshu.com/p/cd55c3d5bcc1

6. Galaxy Consensus Technology Yellow Book Full Text Link (English):

https://www.wanchain.org/files/Wanchain-Galaxy-Consensus-V1.0.pdf

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At present, Wanwei Chain has successfully realized the cross-chain public chain and the certificate is as follows:

Bitcoin (BTC)

Ethereum (ETH)

MakerDAO (MKR, Dai)

Chainlink(LINK)

Loopring (LRC)

Gemini Dollar (GUSD)

USDC

We look forward to opening up more public links and certificates in the future.

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About Wanwei Chain

Wanchain is an asset cross-chain + privacy protection + smart contract. The three characteristics create a cross-chain digital asset infrastructure platform to de-centralize the connection and value exchange of different blockchain networks, allowing any individual and organization to be based on Wanchain. Create a decentralized app. As the first cross-chain between Bitcoin, Ethereum and ERC20, Wanwei Chain is fully promoting the development of the fully decentralized PoS consensus mechanism, which is scheduled to be officially launched on the main network by the end of 2019. At the same time, Wanwei Chain teamed up with Telefónica and RIVETZ, Europe's largest mobile operators, to provide blockchain-based mobile security solutions. According to the plan, Wanchain will gradually realize the cross-chain connection with the main public chain and alliance chain of the industry. Wanchain adopts a global ecological operation and currently has offices in Beijing, China, Austin, USA and London, UK.

For more information about Wanchain, please check the official website:

Https://wanchain.org;

You can also view project progress information through Medium:

Https://medium.com/wanchain-foundation

Business Cooperation:

[email protected]

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