Produced | Vernacular Blockchain (ID: hellobtc)
Produced | Vernacular Blockchain (ID: hellobtc)

"If you want to get rich, build roads first."

Originally, there was only one Ethereum in the world, like a big village, where all production and consumption activities were located, blacksmiths, farms, banks, markets...everyone was close to each other, and there was no such thing as "road building" question.

Originally, there was only one Ethereum in the world, like a big village, where all production and consumption activities were located, blacksmiths, farms, banks, markets...everyone was close to each other, and there was no such thing as "road building" question.

Now that the blockchain has officially entered the multi-chain era, there are many other villages opened next to the Ether Village. Although they are not as large as the Ether Village, they all have their own blacksmith shops, farms, banks, and markets...

Gradually, many villagers who disliked the overcrowding and expensiveness of Ether Village "immigrated" to other villages, and gradually the number of people in several villages increased, and the days of Ether Village's dominance were completely over.

Then road construction was officially put on the agenda. After all, there still had to be economic and news exchanges between several villages, and many villagers' funds also needed to be transferred between villages.

first level title

01 
find a bank

There used to be several big money houses in Ether Village, such as Bian'an, Shuibi, etc. As the surrounding villages gradually became prosperous, they also opened branches in other villages, because these money houses have always had a good reputation , so the villagers also trust them.

When we need capital turnover or transfer money to other villages, we often go to these banks. They also provide fund deposit and withdrawal or turnover services in various villages. This is the earliest CEX solution we commonly used.

Strictly speaking, this is not a "bridge" at all, but it is indeed a simple and effective solution, or the only solution before the bridge era.

However, only the bank is not enough. After all, the bank may also go bankrupt, and more importantly, in such a "decentralized" environment as the blockchain, such an important business always needs the help of a "centralized" bank. Deal with it, it's too embarrassing...

first level title

02 
Single Point of External Authentication

Leaving aside the disadvantages of centralization of banks, in many scenarios, banks are completely unable to meet people's requirements.

For example, the bitcoins in the hands of villagers in Bit Village are actually recognized by every village.But this Bitcoin cannot be taken out of the Bit Village, and people want to use Bitcoin in the Ethereum Village or other villages, what should they do?

Someone found a highly respected elder who did not belong to any village, and discussed with him such a thing: if a villager in Bit Village comes to the elder to deposit a sum of bitcoins, the elder will send him a receipt, and this Bills can be freely circulated in the Ethereum village, and the denomination represented by the bills is equivalent to the Bitcoin deposited by the villagers with the elders.

At the same time, the bitcoins deposited by the elders are also "locked" in the elders and cannot be circulated until someone takes a note to "unlock" these bitcoins.

The advantage of doing this is that it is very convenient. When people in Bit Village want to go to Ethereum Village to use their Bitcoins, they only need to find the elders to save money and get the bills. Bills are as easy to use in Ethereum Village as Bitcoins. .

The disadvantage is that although this respected elder has a good reputation, what if he fails to resist the temptation of sugar-coated bullets and runs away with the bitcoins that everyone has deposited?

Those Bitcoin bills circulating in the Ethereum village will directly become a piece of waste paper due to the loss of the endorsement of these deposited Bitcoin assets, causing heavy losses to users. You must not be difficult to see that this is the bridge of "single-point external verification" represented by WBTC.

first level title

03 
Multipoint External Authentication

Since we don't trust the "highly respected" elder, how about finding several elders with good reputations to do the work of accessing, locking, and issuing tickets together?

The reputation and character of each of them can't keep up with the previous "highly respected" elder, but there are so many of them! And they usually have to pledge a large amount of assets to be able to qualify as this "verifier".

Then under the conditions of asset pledge + game, the possibility of them collectively "getting dirty" is much reduced, and they are more reliable than the individual elder on the whole.

native authentication

04 
native authentication

It sounds very high, so what is native verification? Everyone knows that the order of each village is maintained by the police (miners) in the village.

For villages with a long history like Bit Village and Ether Village, the law and order has always been very good, and everyone's trust in the police is also very high. Although the newly rising villages have not yet accumulated enough precipitation, such as Near Village and Cosmos Village also have good reputations and orderly law and order.

What if we transfer assets between two reputable villages under the premise of the collective witness and guarantee of the village police (miners) on both sides?Is it no longer necessary to find one or more elders from the outside world?

Even better, under the witness of the police on both sides, people in the villages on both sides can not only transfer assets, but also send news to each other! The real realization of "speaking from a distance".Obviously, the native verification model is safe and reliable, and there is no need to find someone from the outside, and there is no need to pledge assets...

But the disadvantage is also obvious, that is, the police of two villages have to be involved every time (deploying this kind of native verification bridge between any two chains, developers need to develop and deploy new light weight bridges on the source chain and the target chain) client smart contract), so the flexibility is much worse than the external verification mode.

first level title

05 
Local Verification (Liquidity Network)

This model is basically an extension based on the Bitcoin Lightning Network model. To understand the typical model of this bridge, you must first understand two words: atomic swap and hash time lock.

What do you mean? For example, if a person wants to transfer the Ethereum in his hand from village A to village B, is there any more reliable method than the elders, or even two village policemen?

There really is, and that is a robot without emotion and moral blemishes! Atomic swap based on hash lock is such a robot. The robot receives payment from your address with a hash lock in village A, and specifies an expiration time lock, and then sends the same hash to your address in village B. Locked transfers.

After you discover the transfer at the address in village B, publish the key in village A, unlock the hash lock, and release the funds to the robot. Then the robot unlocks the hash lock with the same key in Village B and gives you the funds. If you don't publish the key, both parties can return their funds through the contract after the time lock expires.

In this case, you don't need to rely on the robot's reputation and moral standards at all, but rely on cryptography to implement Code is Law, called "router".The relay node + contract that provides liquidity constitutes the "robot" above.

summary

06 
summary

At present, the mainstream bridges can be classified into these five categories for the time being. However, the world of blockchain is changing with each passing day. The multi-chain era is officially coming. While each public chain continues to develop technologically, the underlying technology and economic incentives of the bridge And game models, etc. will also continue to develop.

Different scenarios and different needs will definitely have different types of bridges to meet. Let us wait and see the public chain's "Hundred Flowers Blooming" and the cruel "Hundred Bridges War"!