What are the differences between main approaches in decentralised Bridges?

There are several different approaches to building a decentralized bridge, each with its own set of trade-offs in terms of scalability, security, and performance. The main approaches are:

1. Atomic swap: This approach uses smart contracts on both blockchain networks to enable atomic cross-chain transactions. In this approach, assets are locked on one blockchain network, and a corresponding asset is locked on the other blockchain network. If both assets are locked at the same time, the assets are automatically swapped between the two networks. This approach is secure and decentralized, but it can be limited in terms of scalability and requires the use of smart contracts on both blockchain networks.

2. Relay: This approach uses a central intermediary, known as a relay, to facilitate cross-chain transactions. In this approach, assets are locked on one blockchain network, and a corresponding asset is locked on the relay. If both assets are locked at the same time, the assets are automatically swapped between the two networks. This approach is less decentralized than the atomic swap approach and can be more vulnerable to attack.

3. Hash Time Locked Contract (HTLC): This approach uses Hash Time Locked Contracts (HTLCs) to enable cross-chain transactions. In this approach, assets are locked on one blockchain network and a hashed time-locked contract is created on the other blockchain network. If the correct secret is provided within a specific time frame, the assets are automatically unlocked and transferred to the other blockchain network. This approach is more decentralized than the relay approach and does not require a central intermediary. However, it can also be limited in terms of scalability and can be more complex to implement.

4. Proxy tokens: this approach consist in creating a token on a blockchain network that represents an asset on another blockchain network. This enables cross-chain transactions without actually moving the assets between the chains, but with the same value representation, this approach can help to increase scalability and performance, but also may have security issues, and requires coordination and trust from both chains.

Each of these approaches has its own set of trade-offs in terms of security, scalability, and performance, and the right approach will depend on the specific use case. It’s important to consider these trade-offs and choose the approach that best fits the needs of the specific use case.