A safe way to remove objectionable content from the blockchain

Peter has raised a critical concern regarding the use of Zero-Knowledge Proof (ZKP) only validation methods within Bitcoin's Hashed Time-Locked Contracts (HTLCs), highlighting a potential flaw where the necessity to reveal transaction data on-chain could be circumvented. This issue primarily affects the mechanism of HTLCs, as it relies on the publication of a preimage for the completion of a transaction. If a transaction can be validated through ZKPs without the need to disclose the actual transaction data, including the preimage, it jeopardizes the security framework of Lightning Networks. The integrity of "proof of publication" is compromised, shifting to a "proof of validity without data availability," which directly impacts the counterparty's ability to claim their incoming HTLC due to the unavailability of the preimage.

Furthermore, Boris elaborates on the broader implications of deploying ZKP-centric approaches without ensuring data availability. He warns against a future where network dynamics might lean heavily towards ZKPs, risking block data becoming exclusive to a limited number of data providers. This scenario presents a significant data-availability risk and threatens the principle of self-sovereignty for routing nodes within the network. The essence of any ZKP or succinctness design tailored for Bitcoin, according to Boris, must incorporate robust data availability measures. Ensuring that every participant can access raw transactions and not just the validity proofs is paramount to preserving the network's decentralized and open nature.

To mitigate these concerns, Boris proposes that any development in the realm of ZKPs or succinctness for Bitcoin should inherently include mechanisms that guarantee the publication and retrievability of necessary data, such as preimages, on-chain. Moreover, he emphasizes the importance of integrating strong data availability guarantees into these designs to ensure that raw transaction and block data remain accessible to everyone. By prioritizing data availability within the design of ZK systems, there's an opportunity to preemptively address and reduce the space for alternative designs that may compromise on these essential aspects.