What is Vite?
Vite is a universal dApp platform that can support a set of smart contracts, each of which is a state machine with independent state and different operational logic, which can communicate by message delivery.
Our review will be based on Vite Cross chain protocol and Loopring Protocol.
WHAT IS CROSS CHAIN PROTOCOL?
Vite designed a Vite Cross Chain Transfer Protocol (VCTP) in order to support cross chain value transfer of digital assets and eliminate 'Value Island '.
For every asset that needs cross-chain transmission on the target chain, a token that corresponds to it, is needed in the Vite as the voucher of the target Token circulating within
the Vite, which is called the ToT (Token of Token). For example, if you want to transfer the ether in the Ethereum account to Vite, you can issue a ToT with an identifier of ETH in Vite, the initial quantity of TOT should be equal to the total quantity of ether.
There is a Gateway Contract on Vite for each target chain to maintain the mapping relationship between Vite transactions and target chain transactions. In the consensus
group where the contract is located, the node responsible for generating blocks is called VCTP Relay. VCTP Relay needs to be the Vite node and the full node of the target chain at the same time, and listen transactions on both sides. On
the target chain, we also need to deploy a Vite Gateway Contract.
Before VCTP Relay starts to work, the corresponding ToT in Vite should be transferred to the gateway contract. After that, the supply of ToT can only be controlled by the gateway contract, and no one can be added to ensure the 1:1 exchange ratio between the ToT and the target asset. At the same time,so as to ensure that ToT has a full acceptance reserve the assets on the target chain are controlled by the Vite gateway contract, and no user can use it.
CROSS CHAIN PROTOCOL DIAGRAM
The above picture is an example of the cross chain value transmission between the Vite and the Ethereum. When the Ethereum user E1 wants to transfer the token from the Ethereum to the Vite, it can send a transaction to the Vite gateway contract address V , while the user’s address A on the Vite is placed in the parameter. The balance of the transfer will be locked in the gateway contract account and become part of the ToT reserve. After listening to the transaction, the VCTP relay node generates a corresponding account sending transaction of Vite, sending the same amount of ToT to the user’s account A in the Vite. In the picture, ⃝1 and ⃝2 respectively indicate that E1 and E2 transfer to Vite account A and B. It should be noted that if
the user does not specify the Vite address when transferring, the contract will reject the transaction. The reverse flow is shown in ⃝3 , When the user A launches transfering from the Vite account to the Ethereum account, a transaction will be sent to the Vite gateway
contract, transfers to a certain quantity of ToT, and specifies the reception address E1 of the Ethereum in the transaction. The VCTP relay node will generate the corresponding response block on the Ethereum Gateway contract, and
package a transaction of the Ethereum to the Vite gateway contract on the Ethereum. In the Ethereum , the Vite gateway contract will verify whether this transaction is initiated by a trusted VCTP relay, and then the same amount of ether
is transferred from the Vite gateway contract to the target account E1.
All cross chain relay nodes will monitor the target network, and they can verify whether each cross chain transaction is correct and reach consensus within the consensus group. But snapshot consensus group will not monitor the transaction of the target chain, nor will it verify whether the mapping between the two chains is correct. If the target network is rolled back or hard forked, the mapped transactions in the Vite system cannot be rolled back;similarly, if the cross chain transactions in the Vite are rolled back, the corresponding transaction of the target network can not be rolled back at the same time. Therefore, when doing cross - chain transactions, it is necessary to deal with transaction rollback in contract logic. At the same time, as described in the 4.4 part, we need to set a delay parameter for the cross chain Relay consensus group.
WHAT IS LOOPRING PROTOCOL?
Loopring protocol  is an open protocol to build a decentralized asset trading network. Compared to other DEX solutions, the Loopring protocol is based on the multiparty loop matching, which provides a dual authorization technology to prevent preemptive transactions and is fully open.
We build the Loopring protocol into Vite, which is conducive to promoting the circulation of digital assets in Vite, so that the whole value system can be circulated. In this value system, users can issue their own digital assets, transfer assets outside the chain through VCTP, and use
the Loopring protocol to achieve asset exchange. The whole process can be completed within the Vite system and is completely decentralized.
In Vite, Loopring Protocol Smart contract (LPSC) is a part of the Vite system. Asset transfer authorization and multi-party atomic protection are all supported in the Vite.
The Loopring relay is still open to fully integrate with its own ecosystem.
Users can use vite to pay for asset exchange transactions, so the earned token by miners of Looping who perform loop matching in the Vite platform is still vite.