Achain is a decentralized public blockchain platform. Developers can use the Achain platform to publish tokens, smart contracts and blockchain systems in a simple, fast and secure manner. Achain is committed to building a blockchain network system with global information interconnection, value interconnection and trust exchange. Achain’s philosophy and technical mission is to build a blockchain world without barriers.

1. Project introduction

Achain's unique RDPOS distributed consensus mechanism realizes a Turing complete smart contract virtual machine with independent intellectual property rights, with on-chain transaction performance up to 1,000 TPS. It is a simple, fast and secure blockchain platform. Users can use Achain to quickly deploy enterprise-level decentralized applications such as digital assets and smart contracts. ACT coins have the value of the Achain ecosystem. Coin holders can participate in community activities such as creating and publishing smart contracts, accessing web services, voting agents, and making profits.

Project Features

Stability
Stability is a necessary requirement to ensure Achain is available. Blockchain comes with its own decentralized characteristics, and decentralized networks are usually complex and full of uncertainty. Therefore, we abstract and simplify blockchain with modular design tools, and run smart contracts by building a modular virtual machine, Lua Virtual Machine (hereinafter referred to as LVM), can bring two benefits to this design. First, optimize LVM performance to directly improve contract execution efficiency and reduce interference factors caused by system coupling; second, weaken the correlation between the blockchain network and the running status of smart contracts. Even if there are problems with contract execution or the virtual machine is running abnormally, the stability of the blockchain network can still be guaranteed.

Security
PoW has made an indelible contribution to the security of the Bitcoin network, but due to the growing demand for mining and increased computing power difficulty, almost all rights are concentrated in the hands of miners and mining pools. Through professional cooperation, they have actually become highly centralized "central servers". If more than 51% of the computing power is combined, most Bitcoin transactions can theoretically be controlled, such as the DOS (Denial of Service) attacks we are familiar with. In addition, the high power consumption is also criticized. Compared with the PoW model, the PoS model is still developing, and these development directions are mainly based on security and application. PoS mode has a great security advantage over PoW mode, but the premise is to attract enough holders to carry out PoS mining in order to fully utilize the security advantages. DPoS is an improvement of PoS, and Achain has innovated a more commercially universal RDPoS consensus mechanism. With the same security as DPoS, the block response can theoretically be improved and the stability and security of the network can be increased. In addition, Achain innovatively proposed an intelligent sandbox mechanism. Anyone's contract is first tested in a smart sandbox. Achain will conduct full-path automated testing and continuously monitor its operating status. If the health level deteriorates, or vulnerabilities are found. The network will terminate it by itself to avoid the damage to the blockchain ecosystem due to the problematic contract.

Scalability
Scalability is proposed to solve the problem of information islands where blockchains are incompatible with each other. First of all, we believe that upgrading and forking are one of the effective ways of network evolution, and after forking, a main chain and several sub-chains are formed. The main chain and the sub-chain are completely peer from a technical perspective, but they are set different identifiers based on community consensus. Each sub-chain can be customized according to different commercial applications. By building VEPs between sub-chains, it works similar to a gateway, and information and value can be exchanged between sub-chains through VEP. Through such collaboration, a multi-application blockchain ecosystem can be formed. Not only that, non-blockchain online data will also be included in the Achain ecosystem, supplemented by smart contracts, which can respond to events in the real world.

Easy to use
Achain achieves ease of use through two aspects. First, provide a blockchain as aService (BaaS) to lower the threshold for use by enterprises and individuals. Through network forking, data customization, smart contract release and upgrade, asset transaction monitoring, etc. and supplemented by visual functions, blockchain applications are made simple and easy to use. Second, Achain provides support for multiple languages, from Lua, C++ to Java, allowing developers of different platforms to develop conveniently.

Application Scenarios

Supply Chain Finance
Supply chain finance is a financial service where financial institutions (usually banks) focus on core enterprises to manage the capital flow and logistics of upstream and downstream small and medium-sized enterprises, and by integrating information, it controls risks to the lowest level. It is one of the industries that have developed rapidly in recent years. Due to the high cost of establishing credit, financial institutions have to act cautiously based on risk control and often miss out on some high-quality projects. Achain can help enterprises and financial institutions reconstruct their credit systems and establish more efficient supply chain finance.

Under the core enterprises as the endorsement, a blockchain platform for warehousing, logistics, digital bills and enterprise credit reporting is established through Achain. It can realize the information on goods, warehousing, logistics and accounts receivable witnessed by upstream and downstream enterprises and financial institutions in the supply chain. The issuance, confirmation, circulation, splitting and acceptance of digital notes are triggered by each participant in the supply chain through contracts. The triggering conditions can be based on changes in the data status in the warehousing, logistics blockchain, and core enterprise databases. The triggering rules are compiled according to the contracts of the participating parties. Acts that comply with or violate the rules will be recorded on the credit reporting blockchain and cannot be tampered with.

Achain leverages the advantages of BaaS, smart sandboxing and other technologies to enable rapid deployment. By quickly forking the unnecessary blockchain network at low cost, establishing a connection protocol using VEP, and realizing event-driven by integrating data. All participants can jointly verify the authenticity of the data, thereby ensuring smooth transfer of funds in the supply chain and improving collaboration efficiency.

Product traceability
The retail industry naturally has the characteristics of fragmented transaction data, diversified transaction nodes, and complex transaction networks. People's communication
When purchasing goods through online malls or offline supermarkets, the packaging will be marked with the origin information, production date, and manufacturer. But it is difficult for us to judge the authenticity of this information. Because of the profit margin of fraud, high-value goods such as diamonds, leather bags, skin care products are more likely to have fakes. Falsification not only harms the interests of consumers, but also damages the reputation and brand image of merchants, but society also has to consume funds and manpower to exercise legal supervision and legal sanctions. There are currently several pain points for product traceability: First, product traceability needs not only to trace to the production link, but also to the circulation link. This will inevitably add more joint endorsement of the subjects, and the difficulty of cross-organizational collaboration can be imagined; second, whether it is a manufacturer or a logistics provider, the system used must be centralized and there is an information island problem; third, the centralized system has the risk of individuals doing evil.

In response to the above three pain points, Achain proposes a corresponding solution - blockchain + Internet of Things. With the help of the Internet of Things, data from the production and logistics links can be collected in real time through smart devices and connected to Achain through VEP and stored in the traceability network. The unique data storage structure and distributed ledger technology of blockchain ensure that the data on the chain cannot be tampered with. At the same time, asymmetric encryption and relative anonymity can ensure that the core information of the enterprise is not leaked. When consumers need to query product information, they can trace all the information of the product as long as they know the product code and production batch.

Technical Overview
Contract and LVM implementation
Traditional smart contracts are limited to the input and output of data on the chain, which can only support some simple application scenarios. Because of this, Achain redefined the smart contract. In addition to on-chain data, it also allows on-chain and off-chain data to interact, and supports event responses to changes in on-chain and off-chain data status. Most of the commercial applications in the real world are very complex, and this complexity is reflected in data structures and logical rules. In order to achieve the above goals, Achain made two preparations in the top-level design. First, abstract potential applications, extract general requirements, and design API interfaces and data structures in advance. The second is to choose a Turing complete language to approach the rules in the real physical world as much as possible.

Consensus mechanism
Due to the characteristics of distribution, blockchain requires a consensus mechanism to operate normally. Currently, the consensus algorithms widely used are mainly: Proof of Work (PoW: Proof of Work), Proof of Equity (PoS: Proof of Stake), Practical Byzantine Fault Tolerance algorithm (PBFT: Practical Byzantine Fault Tolerance), and Delegated Proof of Stake (DPoS: Delegated Proof of Stake). From the perspective of security and practicality, Achain selects DPoS and improves the RDPoS consensus mechanism based on it.

RDPoS not only inherits the advantages of DPoS - it does not require additional computing power to achieve the equity allocation after the block production, but it can also dynamically determine the execution results of the smart contract by the agent or all nodes based on the transaction status of the network.

Achain as a public chain, forming community consensus is inseparable from the support of Token. Holding a token can not only obtain basic blockchain services such as contract release and network fork, but also participate in voting and become a proxy node to provide services to receive token rewards. Achain named this token ACT, and each ACT holder is called a stakeholder, and the corresponding voting weight is allocated according to the number of ACT held. Agent nodes are voted on by the stakeholder. The top 99 agents with the largest number of votes take turns to verify transactions, and the order is determined by all proxy nodes and ensure that they cannot be tampered with. Agents can benefit from working normally, but otherwise, if they work abnormally or fail to work, they will be punished.

Account Model
In the blockchain network, the account address is a solution designed for secure exchange. The account, public key, and private key generation process have the following relationship: private key—> public key—> account address. All of these three use Secure Hash Algorithm (SHA) to ensure sufficient security. Hash is a refinement of information, usually its output is much smaller than the input and is a fixed length. With current technical means, hashs with strong encryption must be irreversible. That is, the user's private key information cannot be derived through the user's account address.

Achain uses the Account model instead of Bitcoin's UTXO model (Unspent Transaction Output). Although UTXO is very cleverly designed, supports multiple transactions in parallel, and has relatively good account privacy protection. However, Bitcoin’s account design is a transaction-oriented design, and it is very difficult to implement smart contracts based on UTXO. Smart contracts in the Achain ecosystem often require conditions and states to trigger asset transactions, so Achain finally chose the Account model.

Fork Network
Achain proposes a network suitable for forked based on two considerations. First, maintain strong vitality, and second, meet different application scenarios. First of all, the blockchain network is a community formed by many participants according to certain consensus. The split in consensus causes hard forks to occur, and such forks are sometimes good and sometimes have time difference. Through people's screening and elimination, a group of valuable blockchain networks will eventually be left behind, which is very consistent with the law of continuous self-evolution of species and environment in the self-organized world.

Achain will serve as the starting point of the entire fork network, and may also be called the main chain. The main chain can fork out the sub-chain parallel to it, and the sub-chain can also continue to fork, and all chains have equal status. When a fork occurs, the VEP will record and broadcast the registration information of this sub-chain, such as Genesis block information, sub-chain ID, seed node, digital assets, service identification number, etc. If the fork continues to occur, these registration information will be updated by VEP and synchronized to the entire network again. When interaction is needed between chains, connections can be established through registration of information, that is, service discovery, and information interaction and value exchange can be achieved under the VEP framework. VEP is similar to the DNS service of the Internet, and is responsible for registering information, updating information, and providing access services.

Value Exchange Protocol
VEP is a standard protocol for connecting different blockchain networks. VEP has set guidelines for how to collaborate. It registers the registration information of each chain and provides services to the chains in the trusted list for query and connection requests. VEP supports two application scenarios: cross-chain node interaction and cross-chain contract call. The former uses state changes of data stored on nodes or external data to indirectly generate interactions between contracts and may generate new information. For example: The outstanding loan due as agreed in the contract will affect personal credit. Loan records can be stored on blockchain A, while credit data can be stored on blockchain B, and personal identification information may come from external public databases. The latter is the mutual call between contracts. A simplest example is the exchange of tokens of two chains and keeping the total value unchanged.

Event Driven
Relying on VEP, Achain can realize information interaction and value exchange between chains, and even incorporate non-blockchain data sources such as IOT (Internet of Things), AI (Artificial Intelligence), enterprise or public service databases in the real physical world into the ecosystem, achieving real-time event-Driven.

2. Commentary

Achain is a public blockchain platform. Developers are able to issue tokens, smart contracts, create applications and blockchain systems. Originated in 2015, it was launched on the main website in July 2017. Achain is committed to establishing a global blockchain information exchange and value trading network. Achain was originally developed by the Singapore-based nonprofit Achain Foundation, which is built and maintained by fan communities around the world.

Related links:

https://www.achain.com/

http://www.qukuaiwang.com.cn/szhb/2352.html###

https://www.okex.com/cn/project/98/