Active Privacy-Preserving Contact Tracing Scheme for Infectious Diseases in Cloud Environment

To overcome the issues such as privacy leakage and Health Authorities passive tracking in the current contact tracing scheme, this paper proposes an active privacy-preserving contact tracing scheme for infectious diseases in cloud environments. In this scheme, Telecom Center timely collects participants' information, so that Health Authorities can proactively track the contacts of infectious diseases when needed, and participants needn't to install any additional Apps; Pseudorandom number generator is used to blind the participants' location information to protect their privacy; ElGamal encryption algorithm and its variants are introduced to encrypt the participants' identities, so that the Health Authorities can correctly obtain the information of contacts without revealing anything of other participants. Theoretical analysis and experimental simulation show that the scheme is secure and effective, and it also has good computation performance in large-scale data scenarios.