An Efficient Identity-based Ring Signcryption Scheme

ZhenChao ZHU1,2 Yuqing ZHANG2,* Fengjiao WANG2 1. (Key Lab of Computer Networks and Information Security of Ministry of Education, Xidian University, Xi’an, 710071,P.R.China) 2. (National Computer Network Intrusion Protection Center, GUCAS, Beijing 100049,P.R.China) Abstract: ID-based ring signcryption schemes (IDRSC) are usually derived from bilinear parings, a powerful but computationally expensive primitive. The number of paring computations of all existing ID-based ring signcryption schemes from bilinear pairings grows linearly with the group size, which makes the efficiency of ID-based schemes over traditional schemes questionable. In this paper, we present a new identity-based ring signcryption scheme, which only takes four pairing operations for any group size and the scheme is proven to be indistinguishable against adaptive chosen ciphertext ring attacks (IND-IDRSC-CCA2) and secure against an existential forgery for adaptive chosen messages attacks (EF-IDRSC-ACMA).