A practical approach to solve secure multi-party computation problems

Secure Multi-party Computation (SMC) problems deal with the following situation: Two (or many) parties want to jointly perform a computation. Each party needs to contribute its private input to this computation, but no party should disclose its private inputs to the other parties, or to any third party. With the proliferation of the Internet, SMC problems becomes more and more important. So far no practical solution has emerged, largely because SMC studies have been focusing on zero information disclosure, an ideal security model that is expensive to achieve. Aiming at developing practical solutions to SMC problems, we propose a new paradigm, in which we use an acceptable security model that allows partial information disclosure. Our conjecture is that by lowering the restriction on the security, we can achieve a much better performance. The paradigm is motivated by the observation that in practice people do accept a less secure but much more efficient solution because sometimes disclosing information about their private data to certain degree is a risk that many people would rather take if the performance gain is so significant. Moreover, in our paradigm, the security is adjustable, such that users can adjust the level of security based on their definition of the acceptable security. We have developed a number of techniques under this new paradigm, and are currently conducting extensive studies based on this new paradigm.