HIERARCHICAL IDENTITY-BASED PROXY RE-ENCRYPTION WITHOUT RANDOM ORACLES

作者:Ren, Yanli*; Gu, Dawu; Wang, Shuozhong; Zhang, Xinpengu
来源:International Journal of Foundations of Computer Science, 2010, 21(6): 1049-1063.
DOI:10.1142/S0129054110007726

摘要

In a proxy re-encryption scheme, a semi-trusted proxy converts a ciphertext for Alice into a ciphertext for Bob without seeing the underlying plaintext. A number of solutions have been proposed in public key settings. Hierarchical identity-based cryptography is a generalization of identity-based encryption that mirrors an organizational hierarchy, which allows a root private key generator to distribute the work load by delegating private key generation and identity authentication to lower-level private key generators. In this paper, we propose a hierarchical identity-based proxy re-encryption (HIBPRE) scheme which achieves IND-PrID-CCA2 security without random oracles. This is the first HIBPRE scheme up to now, and our scheme satisfies unidirectionality, non-interactivity and permits multiple re-encryptions.