Extended Nested Dual System Groups, Revisited

The notion of extended nested dual system groups (ENDSG) was recently proposed by Hofheinz et al. [PKC 2015] for constructing almost-tight identity based encryptions (IBE) in the multi-instance, multi-ciphertext (MIMC) setting. However only a composite-order instantiation was proposed and more efficient prime-order instantiations are absent. The paper fills the blank by presenting two constructions. We revise the definition of ENDSG and realize it using prime-order bilinear groups based on Chen and Wee’s prime-order instantiation of nested dual system groups [CRYPTO 2013]. This yields the first almosttight IBE in the prime-order setting achieving weak adaptive security in MIMC scenario under the d-linear (d-Lin) assumption. We further enhanced the revised ENDSG to capture stronger security notions for IBE, including B-weak adaptive security and full adaptive security. We show that our prime-order instantiation is readily B-weak adaptive secure and full adaptive secure without in...

• Type: Journal
• Year: 2016
• Where: PKC
• Authors: Junqing Gong, Jie Chen 0021, Xiaolei Dong, Zhenfu Cao, Shaohua Tang
• Keywords: Cryptology, PKC 2016