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Journal of Applied Mathematics
Volume 2014, Article ID 329198, 7 pages
Research Article

Time-and-ID-Based Proxy Reencryption Scheme

1Department of IT Convergence and Engineering, Kyungil University, Daegu 712-701, Republic of Korea
2School of Computer Science and Engineering, Kyungpook National University, Daegu 702-701, Republic of Korea
3Department of Multimedia, Sungkyul University, Anyang-si 430-742, Republic of Korea

Received 28 December 2013; Accepted 4 February 2014; Published 22 May 2014

Academic Editor: Jongsung Kim

Copyright © 2014 Kambombo Mtonga et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Time- and ID-based proxy reencryption scheme is proposed in this paper in which a type-based proxy reencryption enables the delegator to implement fine-grained policies with one key pair without any additional trust on the proxy. However, in some applications, the time within which the data was sampled or collected is very critical. In such applications, for example, healthcare and criminal investigations, the delegatee may be interested in only some of the messages with some types sampled within some time bound instead of the entire subset. Hence, in order to carter for such situations, in this paper, we propose a time-and-identity-based proxy reencryption scheme that takes into account the time within which the data was collected as a factor to consider when categorizing data in addition to its type. Our scheme is based on Boneh and Boyen identity-based scheme (BB-IBE) and Matsuo’s proxy reencryption scheme for identity-based encryption (IBE to IBE). We prove that our scheme is semantically secure in the standard model.