On the Insecurity of an Identity Based Proxy Re-encryption Scheme

Article type: Research Article

Authors: Wang, Xu An | Yang, Xiaoyuan

Affiliations: Key Laboratory of Information and Network Security, Engineering College of Chinese Armed Police Force Xi'an, 710086, P. R. China. E-mail: wangxahq@yahoo.com.cn

Abstract: At Pairing'07, Matsuo proposed two proxy re-encryption schemes: proxy re-encryption fromCBE to IBE and IBE to IBE. Now both schemes have been standardized by P1363.3workgroup. In this paper, we show that their identity based proxy re-encryption scheme is insecure. We give two attacks to this scheme. The first attack shows that the proxy can re-encrypt any IBE user's ciphertext to be the delegatee's ciphertext. The second attack implies that, if the proxy colludes with any delegatee, the proxy and this delegatee can derive any other IBE user's secret key.

Keywords: Cryptography, identity based proxy re-encryption, attack, insecurity

DOI: 10.3233/FI-2010-227

Journal: Fundamenta Informaticae, vol. 98, no. 2-3, pp. 277-281, 2010