▪️Light-client vs validator-based bridges

There are two main approaches to building blockchain bridges: the light-client approach and the validator-based approach. The primary difference lies in how the bridge, which relies on the target chain, verifies data belonging to the source chain. In Validator-based bridges, this validation is performed by validator nodes, acting as a layer between the source chain and the target chain. However, in Light-client bridges, this verification is conducted by the bridge contract itself. While there are nodes that provide source chain data to the bridge contract, they serve solely as relayers of data, not as verifiers.

Why TeleportDAO opts for the light-client approach?

TeleportDAO employs light-client verification to connect blockchains. Instead of relying on third parties for cross-chain verification, we utilize predefined smart contract rules for this purpose. The light-client approach provides distinct advantages over validator-based architectures.

Security

Validator-based bridges rely on a set of validators to verify cross-chain data. Flaws in the security of these validators, such as a potential leak of their private keys, could result in million-dollar hacks. However, in light-client solutions, verification of cross-chain data is performed by smart contracts. Network nodes provide input for the bridge contract, and the contract checks data validity based on predefined rules. Therefore, the security of the protocol is not tied to the security of third-party nodes.

Capital efficiency

Ensuring the security of validator-based bridges by holding validator nodes accountable for their services requires locking a significant amount of capital by them. The required capital also increases if the bridge intends to transfer higher value from one chain to another. This is because the security of the bridge is dependent on the locked value. In contrast, in light-client bridges, security doesn’t rely on third-party nodes. Network nodes merely provide input for the smart contract, and any incorrect input would be detected and rejected by the smart contract. Thus, they don’t require locking any collateral. Additionally, the security of the bridge is independent of network nodes, allowing the bridge to transfer any value from one chain to another.

Decentralization

Validator-based bridges are maintained by a set of validators. These validators could collude together to censor some users and transactions; for example, they may not allow a user to move funds from one chain to another. On the other hand, in light client bridges, anyone can contribute to maintaining the bridge by providing the source chain data to the bridge contract. Also, as there is no collateral requirement here, it makes it very easy for new nodes to join the network. Therefore, it is not possible to prevent a user from moving assets from one chain to another.