Web 3.0, the next generation Internet, has been envisioned as a fully functional and user-friendly Web where our identities and data are our own. Due to the decentralized blockchain technology, there is no security protection from any centralized organization. In line with this vision, Polkadot was created based on the belief that:No single blockchain can do everything, rather, the future is multi-chain.

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Blockchain bridges are connections that allow tokens and/or arbitrary data to be transferred from one blockchain network to another. Two chains can have different protocols, rules, communities and governance models, but the bridge provides a compatible way to achievesecure interoperability。

Bridges come in many different designs, but they can generally be divided intotwo camps: Centralized bridges that rely on trust or federation, and more decentralized so-called "trustless" bridges. Centralized bridges rely on some type of centralized institution or system to operate, meaning users need to trust the intermediary to use a given application or service.

In contrast, a trustless bridge is one in which users don't have to trust a single entity or authority, but instead trust a mathematical truth built into the code. Trustless interactions are enforced by the technology and/or incentives behind the system, not by promises or legal agreements.

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As a practical example of a bridge chain, it is aDecentralized Insurance Marketplace. One way to build this model on Polkadot is to deploy a dedicated insurance parachain that acts as a marketplace for buyers and sellers of insurance. Suppose Polkadot also includes an oracle parachain that brings external data on-chain, and an Internet of Things (IoT) parachain that aggregates information from off-chain IoT devices.

In the case where you buy flight delay insurance, the policy could be structured in such a way that if the oracle parachain confirms that your flight is delayed, and the IoT parachain confirms that you arrived at the airport on time, the policy would pay out compensation. On-chain, if the insurance parachain receives signals from both the oracle and the IoT parachain, it can use the Ethereum bridge to trigger a transaction using a stablecoin (like Dai) from the insurance company's account to the policyholder's account. This is a relatively simple example of strong interoperability.

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The Substrate blockchain development framework can be used to build parachains (when combined with the Cumulus consensus engine) and separate chains with their own consensus and security. Parachains connected and protected by Polkadot or Kusama relay chains are first-class citizens of the ecosystem, and Substrate-based single chains can also be connected through bridges and communicate with ecosystem parachains.

The Parity team is currently developing a Substrate-based chain-baseduniversal bridge. The bridge consists of multiple components that together enable bidirectional communication between an independent Substrate-based chain and a Polkadot parachain, or between two independent Substrate-based chains. especially,This bridge will also enable Polkadot and Kusama to interactfirst level title

The Web3 Foundation grant program has supported the development of many bridges for the Polkadot ecosystem, including the following:

Interlay A trustless bridge from Bitcoin to Polkadot is being built. Currently in beta, it will allow users to mint Bitcoin-backed assets into PolkaBTC on Polkadot at a 1:1 ratio. PolkaBTC can be used in any application or parachain in the Polkadot ecosystem, just like a native asset, thereby unlocking BTC liquidity for Polkadot's DeFi. Internally, PolkaBTC implements the XCLAIM protocol (https://www.xclaim.io/), which makes the bridge financially trustless, permissionless and censorship resistant. PolkaBTC’s rewarded Beta testnet has been launched at the end of February and has made major improvements to the user experience. Meanwhile, PolkaBTC is being audited by the NCC, and Interlay has begun integrating PolkaBTC with Rococo's other parachains.

Snowfork A universal bridge chain (https://snowbridge.snowfork.com/) is being built between Ethereum and Polkadot. This not only transfers ETH from Ethereum to Polkadot, but also ERC20 assets and arbitrary data. In addition to asset transfers, this bridge chain can also be used for more complex interactions, such as cross-chain smart contract calls. For example, any application built on Polkadot can use the bridge to send Dai directly from one account to another on the Ethereum blockchain.

DarwiniaA permissionless, non-custodial bridge chain protocol is being built with efficient, low-cost decentralized functions for cross-chain token and NFT transfers and other cross-chain operations. The Darwinia bridge integrates technologies such as ultra-light clients, zero-knowledge and optimistic verification mechanisms. Darwinia has launched a bridge with Ethereum, and plans to implement more bridges connecting major heterogeneous blockchains in the future, such as BSC, Tron, Filecoin, etc.

CentrifugeCooperated with ChainSafe to develop a modular, asset-agnostic, multi-directional bridge chain between the Substrate blockchain and Ethereum. ChainBridge allows Centrifuge to move fungible and NFT assets between chains, thereby financing real-world assets in various DeFi products. ChainBridge is open source, and it also allows other teams in the ecosystem to build bridge chains with their projects.

ChainX, an encrypted asset gateway, is planning to bridge with multiple networks and has implemented a BTC-to-Substrate bridge. In this design, the bridge is run by validators who stake in ChainX's PoS consensus and control BTC multisig wallets.

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The future of blockchain internet infrastructure lies in everyone working together in a spirit of collaboration. We are committed to connecting the community to the Substrate and Polkadot ecosystems, and to providing reusable development components that make it easy to build and deploy bridge chains that connect to other blockchains. learn more:

• in our Wiki exist

• exist GitHubexist

• exist Element Discuss bridge chains with others on: https://matrix.to/#/#bridges:web3.foundation

• official websiteofficial websiteLearn more about Polkadot: https://polkadot.network/

• use your favoritemedium, join the Polkadot conversation: https://wiki.polkadot.network/docs/en/community

Ready to create? You can apply for a Grant from the Web3 Foundation here:https://github.com/w3f/General-Grants-Program

Translation: PolkaWorld, the first Chinese community of Polkadothttps://wiki.polkadot.network/docs/en/learn-scams

Original link:https://polkadot.network/polkadot-bridges-connecting-the-polkadot-ecosystem-with-external-networks/

Translation: PolkaWorld, the first Chinese community of Polkadot

Follow the PolkaWorld video account,This Thursday at 7pm, continue to chat live about Phala's parachain auction plan! Click to make an appointment!

This Friday, we will hold an offline Polkadot Meetup in Shanghai, welcome to sign up~ for details"Polkadot & Friends" Official Gathering "Polkadot & Friends" Registration Now! See you in Shanghai on Friday! "