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Author: Admin | 2025-04-28
Attack renders PoS chains not slashable and secure. This attack is fundamental and cannot be solved by modifying the consensus protocol without an extra source of trust. To alleviate this threat, some PoS chains resort to social consensus, where the stakeholders periodically make off-chain decisions on the correct block at the latest height and ignore any other potential forks. However, this approach ties the chain’s security to the participating stakeholders’ subjective opinions. This approach is also called weak subjectivity, which is against the decentralization principle. In addition, since social consensus takes time, most PoS chains impose a very long stake unbonding time in the order of weeks.To protect the PoS chain from long-range attacks, Babylon can checkpoint the PoS chain’s blocks to Bitcoin and implement a fork choice rule with an earlier BTC timestamp. This way, either the attacking fork will have a later BTC timestamp in the BTC canonical chain and will never be chosen by anyone, or in order to be chosen, the attacker will have to create a very long fork of Bitcoin in which the attacking PoS fork has an earlier timestamp, which is economically impractical. Thus, long-range attacks are neutralized by BTC timestamping.In the PoS mechanism of B² Hub, a block needs to go through two checkpoints before it is finally confirmed. Therefore, in the consensus mechanism of B² Hub, after the second checkpoint, we submit the block information and the corresponding validator signature information to Finality Providers. The Finality Providers are nodes that are required to stake BTC and can be slashed when they sign two blocks at the same height using EOTS. The Finality Providers then submits it to B² Hub’s validators to collect Finality Votes. The Validator Node will store the collected Finality Vote signature information in a mempool and broadcast it to light clients of B² Hub. Once ⅔ of the Finality Vote signatures are collected, it can be considered that the block has been finally confirmed.B² Hub, which ensures security through Babylon BTC Staking and BTC Timestamping, will be able to effectively avoid Long-Range Attacks, providing greater security for different Rollups.B² Network Supports Babylon BTC StakingB² Network’s mainnet will support BTC Staking.The BTC Staking feature of B² Rollup will be divided into two phases:Before the mainnet launch of Babylon BTC Staking, B² Rollup will allow users to use BTC to stake for B² Hub validators and get B² Token rewards.After
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