In secure multiparty computation, the enemy of practicality is not usually raw computation — it is rounds. Every back-and-forth of messages between the parties adds a network round-trip, and over a wide-area network those round-trips dominate latency. An MPC protocol that is theoretically elegant but needs many rounds can be useless for anything interactive, like a payment.
US11784803B2, “Round-efficient fully secure solitary multi-party computation with honest majority,” granted to Visa International Service Association on October 10, 2023, is explicitly about that bottleneck. Classified under H04L 9/085 (secret sharing) with signature codes, its title front-loads the three properties that matter: round-efficient, fully secure, honest-majority.
Each of those terms is load-bearing. “Solitary” means a single designated party receives the output — a common real-world pattern where one entity needs the answer and the others are contributing private inputs. “Honest majority” is the trust assumption that more than half the parties follow the protocol, which buys stronger guarantees and simpler constructions than the dishonest-majority case. “Round-efficient” is the optimization the patent claims over that setting.
Why a payments network cares is straightforward: latency budgets at the point of sale are brutal, and any cryptographic protocol that wants to run inside a transaction has to be round-frugal. The inventor team — Badrinarayanan, Mukherjee, Ravi, Miao — overlaps with serious academic MPC work, and the same Visa research group shows up across the biometric and MPC filings, marking a coherent program.
Per the desk's discipline: issued grant (B2), not an application; a protocol-method claim, not a deployed product. A round-efficiency patent is a claim to a construction, not proof that a particular transaction flow uses it.
For the reader tracking the field, this is the maturation signature: the early MPC patents asked “can we do this securely?”; the 2023-era ones ask “can we do it in two rounds instead of five?” When the IP shifts to round counts and concrete efficiency, the technology is being engineered for production, not demonstrated for a paper.