the bridge for the outward expansion and connection of the blockchain-cross-chain technology
Open various market websites, we can see that there are many chains on them, such as Bitcoin, Ethereum, Ripple, Grapefruit, etc., each of which has its own characteristics and problems to be solved. However, it is not difficult to find that each chain is an independent, vertical, and closed system. They cannot exchange value and data with each other. Even the fork of Bitcoin, Bitcoin Cash, cannot be exchanged. They are separated from each other, and the blockchain is like an "island".
Such as Bitcoin and Ethereum, etc., the value exchange between these decentralized blockchains needs to be completed by centralized exchanges.
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1. Why cross-chain is needed
The rapid development of blockchain technology, the emergence of a large number of tokens, the disconnection between blockchains, and the large fluctuations in the value of assets will restrict development, and make it difficult to manage digital assets, requiring various transactions Can be redeemed. Each chain is like an island, which will also reduce the vitality of each chain community and limit the network development of the blockchain. As a result, the value and data exchange between chains are more and more important, and the demand for cross-chain will come out. .
2. What is cross-chain
What is cross-chain? Cross-chain can be understood as a bridge connecting various blockchains to realize the value conversion and information interaction between chains.
Cross-chain value conversion is the exchange of tokens, which is the creation of their own transfer transactions on two chains; cross-chain information exchange is the transmission of information, without changing the structure of the original chain, the realization of information from one chain Pass it to the other chain and copy the same data on both chains.
3. Problems solved by cross-chain
The cross-chain technology connects the blockchain from scattered islands. It is a bridge for block connection and a bridge for block expansion.
4. Cross-chain technology
Cross-chain is a complex process that requires the chain to obtain and verify information outside the chain, and requires nodes to have separate verification capabilities, etc. Currently, cross-chain technology mainly has three implementation modes: 1. Notary mode; 2. Side Chain/relay chain; 3. Hash lock.
1. Notary Public Model
The notary mode is the simplest way to use chain-to-chain interaction. A certain or a group of trusted parties declare that something has happened on the A chain versus the B chain. It has received a lot of attention in the field of permission splitting, and flexible consensus does not require proof of work or proof of interest mechanism.
2. Side chain/relay
The side chain can be compared to a payment wallet. The transaction that was originally carried out on the bank (main chain) is recharged (anchored) to the payment wallet (side chain). The difference is that the payment wallet is solved by a centralized company, and the side chain is solved by a decentralized way of blockchain. The relay chain can be understood as a special side chain, at the level of the protocol layer, and the blockchain itself needs to support this mode.
3. Hash lock
The key technology of Lightning Network is HTLC hash locking technology, which provides a scalable micro-payment channel network. Hash lock is to form a smart contract to ensure that the transfer between any two people can be realized through a "payment" channel, completing the role of "intermediary". Both parties of the transaction freeze part of the money through the smart contract and provide a hash value. Who can match the hash value within the contract setting time, then this part of the frozen money belongs to whom.
Blockchain is a distributed ledger technically, and a value network from a commercial perspective. The more effective nodes that can be connected in the network, the greater the value of the network. Therefore, cross-chain technology is needed to connect and expand different blockchains to form a network and build a highway of value networks.