Forwardable Peerswap Incentives, And Closing Surreptitious Communications Tunnels

The Forwardable Peerswaps protocol offers a novel approach to handling liquidity in the Lightning Network, presenting significant advantages over the traditional splicing method. One of the core benefits of Forwardable Peerswaps is its ability to maintain privacy while ensuring incentive compatibility, contrasting sharply with splicing where service providers might misrepresent their actual available inbound liquidity. In splicing scenarios, providers can sell more liquidity than they possess, which ultimately results in transaction failures once the real capacity is exceeded. However, Forwardable Peerswaps mitigate this issue by requiring that any inbound liquidity offered must correspond directly to actual outbound capacity from another node, thus aligning incentives and maintaining transparency in transactions.

This protocol operates efficiently in terms of blockchain space utilization as well. Unlike splicing, which requires modifications proportional to the number of channels involved (O(N)), Forwardable Peerswaps only need changes corresponding to the number of channels through which the swap is forwarded, essentially O(1). This structural difference not only saves block space but also simplifies the transaction process by reducing it to potentially just two key transactions – creation and completion of an onchain Hash Time-Locked Contract (HTLC), regardless of how many channels are actually used.

From a participant perspective, Forwardable Peerswaps involve three main roles: the Initiator, Forwarders, and the Acceptor. The Initiator seeks outbound Lightning liquidity in exchange for onchain funds, while the Acceptor agrees to provide this by taking on the new onchain funds and managing the associated inbound Lightning liquidity. Forwarders facilitate this exchange by searching for suitable Acceptors and are compensated by rebalancing their channels without incurring onchain fees. To ensure the integrity of this system and prevent direct bypassing of Forwarders, the protocol includes mechanisms to obfuscate critical information such as public keys and hashes, using cryptographic techniques like addition modulo and homomorphic properties.

One significant challenge addressed by the protocol is the potential misuse of public keys and hashes as covert communication channels, which could undermine the Forwarders' role and disrupt the intended liquidity balances. To combat this, the protocol incorporates steps like randomizing data in public and private keys and modifying the hash handling processes to secure the integrity of transactions and ensure the Forwarders are appropriately compensated for their services.

In summary, Forwardable Peerswaps introduce a robust framework for managing liquidity in the Lightning Network that prioritizes privacy, efficiency, and incentive alignment. By addressing fundamental flaws in previous systems like splicing, it presents a more sustainable and scalable solution for future network operations.