Affiliations: College of Information Engineering, Qingdao University, 266071 Qingdao, China. qduyujia@gmail.com | Institute of Network Security, Shandong University, 250100 Jinan, China | College of Information Engineering, Qingdao University, 266071 Qingdao, China | School of Computer Science and Technology, Soochow University, 215006 Suzhou, China
Note: [] Address for correspondence: College of Information Engineering, Qingdao University, 266071 Qingdao, China
Abstract: In traditional identity-based encryption schemes, security will be entirely lost once secret keys are exposed. However, with more and more use of mobile and unprotected devices, key exposure seems unavoidable. To deal with this problem, we newly propose a forward-secure identity-based public-key encryption scheme. In this primitive, the exposure of the secret key in one period doesn't affect the security of the ciphertext generated in previous periods. Any parameter in our scheme has at most log-squared complexity in terms of the total number of time periods. We also give the semantic security notions of forward-secure identity-based public-key encryption. The proposed scheme is proven semantically secure in the standard model. As far as we are concerned, it is the first forward-secure identity-based public-key encryption scheme without random oracles.
Keywords: forward security, public-key encryption, key exposure, standard model
