Improved Secure Computation over Real Numbers and Its Application to Reliability Engineering

Secure computation over real numbers has recently been proposed for outsourcing computations while maintaining high security. This scheme has had difficulty in practice because it causes an unreasonably large computational complexity in decryption. While previous research resolved this difficulty, problems remain because the encryption is based on a kind of Caesar cipher known to be weak in terms of security. This paper proposes an improvement on the previous research. The key idea is replacing the differential operator used in the encryption and decryption process with another one so that encryption can be altered to use additional secret real numbers. This addition realizes stronger security because hackers must find not only keys but also these secret real numbers.