Affiliations: [a] School of Computer Science, Shaanxi Normal University, Xi'an, Shaanxi, China | [b] Science and Technology on Communication Security Laboratory, Chengdu, Sichuan, China | [c] State Key Laboratory of Information Security, Beijing, China | [d] State Key Laboratory of Integrated Service Networks, Xidian University, Xi'an, Shaanxi, China
Correspondence:
[*]
Corresponding author: Zhiyi Shao, School of Computer Science, Shaanxi Normal University, Xi'an 710119, Shaanxi, China.shaozy@snnu.edu.cn
Abstract: Medical information sharing is one of the most attractive applications of
cloud computing, where searchable encryption is a fascinating solution for
securely and conveniently sharing medical data among different medical
organizers. However, almost all previous works are designed in symmetric key
encryption environment. The only works in public key encryption do not
support keyword trapdoor security, have long ciphertext related to the
number of receivers, do not support receiver revocation without
re-encrypting, and do not preserve the membership of receivers. In this
paper, we propose a searchable encryption supporting multiple receivers for
medical information sharing based on bilinear maps in public key encryption
environment. In the proposed protocol, data owner stores only one copy of
his encrypted file and its corresponding encrypted keywords on cloud for
multiple designated receivers. The keyword ciphertext is significantly
shorter and its length is constant without relation to the number of
designated receivers, i.e., for n receivers the ciphertext length is only
twice the element length in the group. Only the owner knows that with whom
his data is shared, and the access to his data is still under control after
having been put on the cloud. We formally prove the security of keyword
ciphertext based on the intractability of Bilinear Diffie-Hellman problem
and the keyword trapdoor based on Decisional Diffie-Hellman problem.
Keywords: Medical information sharing, searchable encryption, multiple receivers, ciphertext security, trapdoor security
