Babilonia - probabilistic coinjoin and covert betting

The discussion revolves around the comparison and application of two cryptographic protocols, GTT 26 and Babilonia, particularly in the context of cryptocurrency transactions like coinswap and coinjoin. GTT 26 is characterized by its use of an Oblivious Pseudo-Random Function (OPRF), which allows for a complex but highly secure way to handle transactions. This method leverages an exponential set of possible outcomes, enabling applications like lotteries that require representing very small probabilities. However, it necessitates the dealer's secret key for the evaluation and incorporates a swap structure termed "evaluation as a service."

On the other hand, Babilonia simplifies the transaction process by allowing direct responses from the system without needing the dealer’s interaction, provided the player’s guess is correct. This results in a straightforward "one transaction" design, suitable for simpler payment structures like coinjoin or payjoin. It lacks the capability to support functions like lotteries due to its limited range of outcome probabilities.

Further examination reveals that applying Babilonia to coinswap presents unique challenges and advantages. While traditionally, coinswap suffers from amount correlation issues, Babilonia proposes a novel approach to mitigate this through variable transaction fees that are privately negotiated. This not only enhances privacy but also ensures fairness, unlike conventional methods where small, fixed fees do little to obscure transaction correlations. Specifically, Alice and Bob would engage in a dual transaction mechanism where each party creates two output transactions. Each transaction varies slightly in the amount transferred, thereby breaking the link between transaction amounts and preserving privacy.

Claude, presumably another developer or researcher in this field, has contributed a simplified explanation aimed at Bitcoin engineers, which can be accessed here. This resource could potentially clarify the practical implications and technical details for those interested in implementing such cryptographic solutions in real-world scenarios.

In conclusion, while GTT 26 offers robust capabilities for complex betting systems, Babilonia provides a more streamlined and private solution for everyday cryptocurrency transactions, emphasizing its utility in enhancing privacy and flexibility in coinswap applications.