Types of bridges
https://www.blockchainx.tech/bridge-smart-contract-development
Bridges can be classified in different ways based on different criteria. First, let’s take a look at categorization by addiction.
(1) Classification based on dependence:
Asset Dependent: Build a cross chain bridge This is a solution that only serves the purpose of making certain assets available for use on other chains. As this is a resource specific solution, it is not very scalable. #defi Wrapped tokens are a type of token that many users have seen at least once. Wrapped tokens are tokens anchored to the value of other crypto assets, and you can think of them as a kind of security. The most typical example is $ #WBTC(Bitcoin labeled).
Since the same $ BTC cannot be used on the Ethereum network, to use Bitcoin in Ethereum, $ WBTC of the ERC-1 standard is issued, the value of which is pegged 1:20 with $ BTC, and $ BTC equal to the value issued amount blocks the digital safe. In this way, you can use a token that plays the role of Bitcoin on the Ethereum network, and if you want to change $ WBTC into $ BTC, you can burn the $ WBTC issued and extract the stuck $ BTC in the safe.
Chain Dependent: This is a slightly more scalable approach than resource dependent bridges. It is not a specific resource, but a cross-chain solution between specific chains linked by bridges. A typical example is the polygonal bridge, which is a bridge connecting Ethereum and L2 polygons.
Application Dependent: Corresponds to a single application that targets more than one blockchain and treats the service as an instance. This has the advantage of being able to target more than one chain with one instance, instead of deploying the entire application on each chain. However, this cannot be applied to multiple applications at the same time and there is a limitation as different applications have to create different solutions. Typical examples are compound chains and tor chains. They both provide services by writing codes for
1) loan and
2) applications that function as exchanges.
independent : Build a token bridge It means a solution designed with the aim of connecting multiple blockchains without depending on anything. It may seem suitable as a generalized solution that connects every ecosystem, but many of them have trade-offs to achieve scalability at the expense of decentralization and security to some degree. The most representative example is the Cosmos IBC.
(Classification of the bridge by dependence:
(2) Classification according to the method of verification of cross-chain transactions
In addition to classification by dependency, you can also try classification by the cross-chain transaction verification method.
Validation by external validators and federation: In this way, when an external validator detects a transaction request from the source chain, the token transmitted by the transaction is blocked and the corresponding token is issued on the arrival chain. This only occurs when there is an agreement between the validators and the validators check an address that acts as a sort of “mailbox” in the source chain and the mailbox address blocking is also done. As the name “external” suggests, this is how a certain level of trust in the Validator occurs.
Lightweight Clients and Relays: Observers monitor events that occur on the source chain and create cryptographic evidence of past events that have occurred on that chain. This proof is sent along with the block header to the contract (light customer) on the coverage chain, and after verifying the information received there, the specified action is performed.
While this method has the advantage of not entrusting the trust to a third party, it has the disadvantage of having to develop a smart contract on the cover chain and the cost because the analysis and verification of the proof of status provided by the chain of origin itself involves a commission. The downside is that this can happen a lot.
Types of bridges https://www.blockchainx.tech/bridge-smart-contract-development Bridges can be classified in different ways based on different criteria. First, let’s take a look at categorization by addiction.
(1) Classification based on dependence:
Asset Dependent: Build a cross chain bridge This is a solution that only serves the purpose of making certain assets available for use on other chains. As this is a resource specific solution, it is not very scalable. #defi Wrapped tokens are a type of token that many users have seen at least once. Wrapped tokens are tokens anchored to the value of other crypto assets, and you can think of them as a kind of security. The most typical example is $ #WBTC(Bitcoin labeled).
Since the same $ BTC cannot be used on the Ethereum network, to use Bitcoin in Ethereum, $ WBTC of the ERC-1 standard is issued, the value of which is pegged 1:20 with $ BTC, and $ BTC equal to the value issued amount blocks the digital safe. In this way, you can use a token that plays the role of Bitcoin on the Ethereum network, and if you want to change $ WBTC into $ BTC, you can burn the $ WBTC issued and extract the stuck $ BTC in the safe. Chain Dependent: This is a slightly more scalable approach than resource dependent bridges. It is not a specific resource, but a cross-chain solution between specific chains linked by bridges. A typical example is the polygonal bridge, which is a bridge connecting Ethereum and L2 polygons.
Application Dependent: Corresponds to a single application that targets more than one blockchain and treats the service as an instance. This has the advantage of being able to target more than one chain with one instance, instead of deploying the entire application on each chain. However, this cannot be applied to multiple applications at the same time and there is a limitation as different applications have to create different solutions. Typical examples are compound chains and tor chains. They both provide services by writing codes for
1) loan and
2) applications that function as exchanges.
independent : Build a token bridge It means a solution designed with the aim of connecting multiple blockchains without depending on anything. It may seem suitable as a generalized solution that connects every ecosystem, but many of them have trade-offs to achieve scalability at the expense of decentralization and security to some degree. The most representative example is the Cosmos IBC.
(Classification of the bridge by dependence:
(2) Classification according to the method of verification of cross-chain transactions
In addition to classification by dependency, you can also try classification by the cross-chain transaction verification method.
Validation by external validators and federation: In this way, when an external validator detects a transaction request from the source chain, the token transmitted by the transaction is blocked and the corresponding token is issued on the arrival chain. This only occurs when there is an agreement between the validators and the validators check an address that acts as a sort of “mailbox” in the source chain and the mailbox address blocking is also done. As the name “external” suggests, this is how a certain level of trust in the Validator occurs.
Lightweight Clients and Relays: Observers monitor events that occur on the source chain and create cryptographic evidence of past events that have occurred on that chain. This proof is sent along with the block header to the contract (light customer) on the coverage chain, and after verifying the information received there, the specified action is performed.
While this method has the advantage of not entrusting the trust to a third party, it has the disadvantage of having to develop a smart contract on the cover chain and the cost because the analysis and verification of the proof of status provided by the chain of origin itself involves a commission. The downside is that this can happen a lot.