We propose an efficient protocol for the evaluation of functions getting their inputs from multiple parties in a way that guarantees the result correctness. In our setting, a worker is trusted with the confidentiality of the inputs and, given this assumption, our protocol guarantees perfect privacy to the clients. Our protocol offers an interesting middle ground between traditional verifiable computation protocols, that usually do not come with privacy guarantees and focus on one or a small number of clients, and secure multi-party computation protocol that distribute the privacy trust between a number of parties, at the cost of much more expensive protocols (especially for 𝖭𝖯 functions and functions that do not admit an efficient static circuit representation) and a demanding infrastructure of independently managed servers interacting in multiple rounds. By contrast, our protocol is single-pass: the clients submit their inputs asynchronously, and everyone can collect the result at any later time. We present three unrelated applications of our technique: solving a system of linear equations, an auction scheme and the search of the shortest path in a shared graph. These examples illustrate the ease of use and the advantage in terms of complexity of our approach. We made a prototype implementation that illustrates the practicality of our solution.

We propose an efficient and simple protocol for the evaluation of functions getting their inputs from multiple parties in a way that guarantees the correctness of the computation to everyone and the perfect privacy of the inputs as long as the worker is honest.

We investigate the problem of solving traditional combinatorial graph problems using secure multi-party computation techniques, focusing on the shortest path and the maximum flow problems. To the best of our knowledge, this is the first time these problems have been addressed in a general multi-party computation setting. Our study highlights several complexity gaps and suggests the exploration of various trade-offs, while also offering protocols that are efficient enough to solve real-world problems.

We propose a new encryption primitive, commitment consistent encryption (CCE), and instances of this primitive that enable building the first universally verifiable voting schemes with a perfectly private audit trail (PPAT) and practical complexity. That is: These properties make it possible to introduce election verifiability in large scale elections as a pure benefit, that is, without loss of privacy compared to a non-verifiable scheme and at a similar level of efficiency. We propose different approaches for constructing voting schemes with PPAT from CCE, as well as two efficient CCE constructions: one is tailored for elections with a small number of candidates, while the second is suitable for elections with complex ballots.