What do you think of the latest collaboration between @BSquaredNetwork and @babylon_chain? One is a BTC modular expansion solution provider that launched the B² Hub modular DA layer, and the other is a BTC second-layer POS security pledge service provider that brings native asset pledge interest generation into the BTC network.
The combination of the two is similar to the combination of Celestia modular DA layer + Eigenlayer shared security layer? Next, let me analyze the technical implementation process:

According to the announcement, both the B² Hub and B² Rollup layers of this cooperation will use Babylon’s BTC pledge to enhance security and support BTC LSD and BTC Restaking functions.

Why does BTC staking provide security for B² internal components? Take B² Hub as an example to further illustrate:

1) B² Hub is a key component in the DA layer of B² Network. It is equivalent to a decentralized verification network. It will handle Sequencer filtering, distributed Storage storage, Prove processing of data and proofs from the ZK-Rollup layer, Indexer maintenance after generating Commitment and sending inscription to the BTC main network, and verifying the result of Commitment challenge for challengers, etc.

It should be said that every key step in B² Hub involves the verification and governance of a decentralized Validators network.

The question is, how to ensure the security of this verification network?

One idea is to use Validators to perform POS pledges on the local network, and perform rewards and slashes in accordance with the agreed specifications. The pledged assets are the tokens of the local second-tier chain. This solution is theoretically feasible, but it lacks higher-level security; another The first idea is to let these Validators directly participate in the asset pledge of the BTC main network, and then use them to ensure the security of the external POS system.

Obviously, when B² Hub cooperates with Babylon, it will advance to the second security solution, which will enhance the security of its decentralized verification network.

2) How does the BTC pledge system introduced by Babylon ensure the security of the external POS system?

1. Time lock. Babylon will lock the assets requested to be pledged by the main network for a certain period of time. During the locking period, the pledger cannot use the pledged assets. This will also become a restriction for the pledger on the POS external system, making the pledger must Follow the rules of the external POS system. Once a violation occurs, the pledged assets may not be redeemable;

2. One-time signature EOTS, Babylon introduces a signature scheme. If the same private key is used to sign two different blocks at the same block height, the private key will be exposed. This means that if a staker attempts to double-spend, his private key will be leaked and his staked BTC assets will be forfeited by Slash. EOTS signature can be implemented through BTC’s native Schnorr signature, and multi-signature governance equivalent to BTC’s security level will take effect;

3. In the final round of multi-signature consensus, Babylon stipulates that a block will only be finalized when it receives the EOTS signatures of more than 2/3 of the BTC pledgers, which means that the evil node wants to proceed when the signatures are less than 1/3. When double-signing, the private key will be exposed and the pledged assets will be slashed. This mechanism further ensures that pledge nodes can participate in POS system governance in accordance with regulations.

3) So, how does Babylon provide security support for B² Hub? in particular:

First of all, B² Hub’s decentralized verification network needs to reach a consensus mechanism, including nodes pledging BTC and B² tokens to participate in governance. The use of a dual asset pledge mechanism can avoid some nodes in the second-layer network from trying to control by purchasing large amounts of B² tokens. network because it must have a large amount of BTC assets in a pledged state on the mainnet at the same time.

Secondly, B² Hub has set up Epoch consensus and CheckPoint. During each Epoch, verification nodes need to conduct governance votes on all on-chain actions, and the final determination of each POS second-layer chain block must wait for at least two BTC mainnets to be released. Block timestamp. This will give enough time for the second layer's own governance mechanism to determine the certainty of the state transition to punish possible evil behaviors;

Finally, Babylon cleverly utilizes BTC timestamps to prevent “long-range attacks.” To put it simply, if a node in the POS chain attempts to create a fork on the second layer and builds a longer forked chain, if the new forked chain is longer than the original chain, it will cause damage to the consensus of the entire second-layer network.

It will take a long time for malicious nodes to plan and prepare to achieve their goals. If the blocks of the POS chain can be linked to the timestamps of the Bitcoin mainnet blocks, so that each POS block corresponds to a Bitcoin block, wouldn’t the problem be solved?

Just imagine, if a malicious node in the POS chain attempts to carry out a long-range attack, it will not only need to obtain the longest chain of consecutive blocks on the POS chain, but also need to achieve the longest chain control on the BTC network. If the cost of manipulating the POS chain may be high, It is lower, and to control the BTC mainnet chain at this stage, the computing power cost is estimated to be astronomical.

Of course, in addition to enhancing security, B² Hub and Babylon are also of great benefit to the ecological interoperability of both parties, and can bring direct re-pledge benefits. Users who pledge BTC to the Validator of B² Hub can obtain token rewards provided by B². When Babylon After staking the mainnet online, you can also enjoy the re-staking benefits of the Babylon ecosystem. You can get stBTC by staking BTC, and you can also get the double benefits of staking in the B² Hub staking contract and the Babylong staking contract.

that's all

The modular DA provided by Celestia has become a more cost-effective choice for Ethereum's Rollup layer 2. The long-term positioning of B² Hub is also to serve as a modular DA layer to provide services for multiple Rollup layer 2 chains in the BTC ecosystem.

B² Hub's original off-chain zk-Rollup proof system and BitVM-style Commitment mainnet challenge are equivalent to realizing a POS off-chain consensus that is close to the BTC mainnet security consensus. After all, there is a challenger mechanism, and node behavior is highly likely. Will be considered to be "optimistic".

Eigenlayer's re-pledge ensures the provision of EigenDA node services by giving Ethereum nodes gain Buffs, which is equivalent to enhancing node verification capabilities through an economic incentive mechanism. By analogy, the role of Babylon is actually very similar to the Function provided by Eigenlayer.

All in all, would it be easier to understand if we compare the impact of this cooperation between B² Network and Babylon on the BTC layer2 ecosystem to the effect of Celestia DA and Eigenlayer Restaking on Ethereum layer2?