Title: Non-transferable proxy re-encryption for multiple groups

Authors: Ei Mon Cho; Lwin San; Takeshi Koshiba

Addresses: Graduate School of Science and Engineering, Saitama University, Saitama, Japan ' Graduate School of Science and Engineering, Saitama University, Saitama, Japan ' Faculty of Education and Integrated Arts and Sciences, Waseda University, Tokyo, Japan

Abstract: In proxy re-encryption (PRE) scheme, the message is sent by a delegator to a delegatee with help of the trusted third party proxy without knowing the existing plaintext. It is known that non-transferable PRE schemes solve some problems of the naive PRE schemes. Some non-transferable PRE scheme is extended to group-based schemes, where the proxy diverts a ciphertext for a group into another group, but the existing schemes have the proxy colluding problem. To resolve the proxy colluding problem for group-based PRE schemes, we propose a non-transferable PRE scheme for multiple groups. In our scheme, there are three sub-processes, which are based on a non-transferable PRE scheme and a group signature. We show that our scheme provides the security for a delegator Alice, a delegatee Bob in the same group with Alice, and another delegatee Charlie in a different group from Alice.

Keywords: proxy re-encryption; PRE; non-transferability; group signature; multiple groups.

DOI: 10.1504/IJSSC.2018.091192

International Journal of Space-Based and Situated Computing, 2018 Vol.8 No.1, pp.20 - 29

Received: 17 Oct 2017
Accepted: 15 Dec 2017
Published online: 15 Apr 2018 *