[Short general description]: PCHAIN is a new system with native support for multi-chain applications, making it possible for large-scale enterprise applications based on smart contracts.
[Main problems tackled]:
1) The first native multi-chain architecture that supports EVM, with a consensus of POS based on multi-layer sharding mechanism that tremendously improves the performance of transactions.
2) A new Oracle mechanism based on the knowledge graph makes it easier to encapsulate smart contracts. PCHAIN's endogenous W3C-compliant smart data effectively addresses the issue of non-intelligence in smart contracts and can become a fundamental element of smart contracts, just like the market exchange rate data from the external.
3) The goal of PCHAIN Smart Data is to generate valuable data that filters out noise and make it an integral part of Oracle. These smart data can be used in various PCHAIN's smart contracts and other cross-chain requests. Smart data, on the one hand, can serve as an intermediary between blockchain and articial intelligence, and on the other hand, facilitates the integration of blockchain with big data. Therefore, it has a vast application prospects, including decentralized question and answer, forecasting markets, the construction of distributed knowledge graph, social networks, digital identities and others.
4) The trunked cross-chain solution makes the exchange of digital currency and digital assets more convenient. Various Token (e.g. BCH, ERC20) can be directly used to invoke smart contracts in PCHAIN.
[Main contribution proposal]:
In response to the defect of single-chain method which supports smart contracts, a multi-chain approach is proposed to improve the support for DApp. The multichain approach has a new structure of a main chain and multiple side chains.
When you create a new DApp (e.g. a new smart contract), a side chain will be created :
1) Invocation of Smart Contract for Non-native Token - When the toolkit provided by PCHAIN, which is used on other blockchains, invokes the smart contract of PCHAIN with a certain number of Tokens in this blockchain, the exchange rate between the Token and PCH (Token of PCHAIN) will be acquired by the toolkit firstly through the smart data in Knowledge Graph. When the convertible PCH is enough to run the called smart contract, the toolkit will transfer corresponding number of Tokens to PCHAIN and consume the corresponding quantity of PCH of PCHAIN to invoke the smart contract.
2) Consensus of Sharding - PCHAIN supports Shardings at different levels and offers a choice of POS consensus mechanisms to improve the efficiency of operation and storage and support chain expansion.
3) Knowledge graph and Smart data -PCHAIN writes standard RDF triples into the built-in blockchain knowledge base to form Smart Data. The goal of PCHAIN Smart Data is to generate valuable data, lter the noise of the data, and become an element of the smart contracts Oracle.
4) Supporting EVM - EVM completes the logic of business and takes control of all instructions and thus to resist malicious code logic. While making reasonable and transparent calculations of costs of calling smart contracts by implementing Turing complete Solidity.
[Innovation]: PCHAIN is the first blockchain that supports Smart Data, based on which knowledge graph is formed and smart contract can be executed within a closed loop. Every DApp has its own chain tha makes it easy to browse and restore transactions.
1) Supporting large-scale transactions - When the accumulation of transactions of multiple DApp results in a large overall scale, the scale of the corresponding side chain is relatively small. Now every side chain grows itself without affecting the main chain and other side chains. When the scale of transactions of single DApp is large, the computing power of the whole network focus on the chain because of incentive mechanism to ensure blocks can be produced in time and transactions can be completed aș soon as possible. If there are many DApps and many transactions in each DApps, the system will be busy and it is hard to avoid congestion. However, this situation is less likely to happen.
2) New consensus make computing parallelism - Under the original POW mechanism of the public blockchain, every node mines and thus there is a high probability to produce new blocks at same time. However the probability of fork also is high. Under the new consensus mechanism, a group is formed for consensus and the probability of fork is reduced. Meanwhile, with the new mechanism, when a group reaches a consensus, intensive CPU operation is not needed anymore, which can save a lot of power. All nodes can be divided into many small groups and each group has a consensus on one chain, which is concurrent consensus. Besides, groups have intersection, i.e., a node may join consensuses of many chains. Therefore, the computing power is fully utilized and the growing of PCHAIN is smooth.
3) Supporting smart contract update - supports upgrade of smart contract through the methods above.
4) High fault tolerance - In construction of PCHAIN, main chain just records, and errors will not occur in theory. When some error happens in a side chain, main chain and other side chains are not a affected and only corresponding side chain needs to be corrected.
5) Expansibility - It is easy to deploy a new DApp with expanding a new side chain. Under the consensus mechanism, the growing of new chain does not cause much burden.