cross-chain bridge

Users may quickly access other protocols thanks to a cross-chain bridge that joins several blockchains and enables the transfer of assets and data across them. Because blockchains act as isolated silos that cannot communicate with one another, bridges are required.

For instance, you cannot use ETH or BTC on the other. In contrast, your credit card can be used at several providers with legacy systems like banking.

The development of the blockchain ecosystem has increased interest in blockchain bridges. In the past, few people were interested in using other blockchains; consumers were more inclined to utilize Ethereum for decentralized applications (dApps) or Bitcoin for high-value payments.

However, the shortcomings of these well-known blockchains, like Ethereum, prompted the creation of additional platforms.

Benefits including lower transaction fees, increased network throughput, and access to novel yield-earning activities were provided by these new chains.

Users were unable to transfer assets from earlier platforms to these more recent blockchain networks without any issues.

Imagine you needed to use a Layer 2 network like Polygon and you had money on the Ethereum network (ETH). Your best bet would be to use a centralized exchange, like Coinbase or Binance, to swap ETH for MATIC.

To use the network, you would then send the tokens to your Polygon chain wallet address. However, what if you had to transfer money back to Ethereum? You would have to go through the conversion process again.

The issue was resolved with a cross-chain bridge, which made it simpler to transfer money between various networks. Wanchain, one of the first cross-chain bridges, was introduced in 2018. Since then, hundreds of bridges with distinctive tradeoffs, advantages, and applications have gone live.

We examine the operation of cross-chain bridges in the sections that follow.

Specifically, how do bridges transfer assets between several blockchain networks? And why does that matter?

How does a cross-chain bridge work?

Most cross-chain bridges use a lock-and-mint model for moving value between chains. Here's how that works in practice: 
1. John pays the transaction fee and transmits units of Token A to a specific address on the source chain (such as Ethereum).

2. A trusted validator or a trusted custodian has John's Token A locked up in a smart contract.

3. On the final blockchain, Token B is printed in equal amounts (e.g. Polygon).

4. John receives Token B at the address associated with her wallet and is free to utilize it to complete transactions on the new network.