Emulating OP_RAND

The correspondence inquires about the viability of implementing probabilistic Hashed Time-Locked Contracts (HTLCs) within the Lightning Network (LN), proposing a shift from traditional HTLCs to a model that facilitates microtransactions through probabilistic payments. The concept hinges on creating an output for a payment with a low probability but higher value, aimed at making small transactions economically feasible. Specifically, the scenario presented involves Alice wanting to transfer a nominal amount to Bob, which is not practical under current mechanisms. Instead, Alice would generate an output that pays Bob a significantly larger sum with a slim chance of occurrence. This setup ensures that if the channel remains off-chain until the HTLC's resolution, a mutual channel update would suffice for the transaction. However, if the channel were to be closed forcibly, the probabilistic payment would then be executed.

Further inquiry delves into whether this proposed scheme could be adapted to function based on conditional resolutions tied to an HTLC, such as allowing Alice to reclaim funds after a specified block duration or enabling Bob to claim funds with a minuscule probability upon revealing a preimage for a given hash digest. Moreover, the question extends to the compatibility of this system with PTLC resolution mechanisms, particularly focusing on the use of signature adaptors and ensuring that Bob cannot determine his ability to claim the money before accepting the probabilistic HTLC.

The discussion also explores the feasibility of incorporating LN-Penalty revocation paths within this framework. Such paths would dictate specific actions and conditions for both parties depending on who initiates the on-chain publication of the HTLC, with distinct commitment transactions outlined for Alice and Bob. This segment underscores the importance of determining the initiator based on the published commitment transaction version.

Additionally, the sender expresses interest in understanding whether the proposed protocol could facilitate the pre-arrangement of most interactive steps prior to establishing the specific probability for a payment. This would potentially allow for smoother transaction processes during channel setup or intervals between forwarding HTLCs by sharing public keys and commitments in advance. The aim is to streamline the process to select the appropriate number of commitments to achieve the desired probability without necessitating further interaction beyond the initial setup, ideally aligning with the interactivity requirements akin to those of using MuSig2 signature adaptors.

Overall, the inquiry seeks detailed insights into the adaptability of the proposed probabilistic HTLC scheme within the Lightning Network, its integration with existing cryptographic solutions like PTLC and LN-Penalty, and the potential for simplifying the interaction process to facilitate efficient microtransactions.