Anonymous IBE, Leakage Resilience and Circular Security from New Assumptions
Name
2017-967.pdf
Description
Accepted version
Size
600 KB
Format
Adobe PDF
Checksum (MD5)
6037c2ab2e8ee74bb2f1193ecfd85eeb
Author(s)
Brakerski, Zvika
Lombardi, Alex
Segev, Gil
Vaikuntanathan, Vinod
Date Issued
2018
Publisher
Springer International Publishing
Citation
Brakerski, Zvika, Lombardi, Alex, Segev, Gil and Vaikuntanathan, Vinod. 2018. "Anonymous IBE, Leakage Resilience and Circular Security from New Assumptions."
Version
Author's final manuscript
Abstract
© International Association for Cryptologic Research 2018. In anonymous identity-based encryption (IBE), ciphertexts not only hide their corresponding messages, but also their target identity. We construct an anonymous IBE scheme based on the Computational Diffie-Hellman (CDH) assumption in general groups (and thus, as a special case, based on the hardness of factoring Blum integers). Our approach extends and refines the recent tree-based approach of Cho et al. (CRYPTO’17) and Döttling and Garg (CRYPTO’17). Whereas the tools underlying their approach do not seem to provide any form of anonymity, we introduce two new building blocks which we utilize for achieving anonymity: blind garbled circuits (which we construct based on any one-way function), and blind batch encryption (which we construct based on CDH). We then further demonstrate the applicability of our newly-developed tools by showing that batch encryption implies a public-key encryption scheme that is both resilient to leakage of a (1o(1)) -fraction of its secret key, and KDM secure (or circular secure) with respect to all linear functions of its secret key (which, in turn, is known to imply KDM security for bounded-size circuits). These yield the first high-rate leakage-resilient encryption scheme and the first KDM-secure encryption scheme based on the CDH or Factoring assumptions. Finally, relying on our techniques we also construct a batch encryption scheme based on the hardness of the Learning Parity with Noise (LPN) problem, albeit with very small noise rate Ω(log2(n)/n). Although this batch encryption scheme is not blind, we show that it still implies standard (i.e., non-anonymous) IBE, leakage resilience and KDM security. IBE and high-rate leakage resilience were not previously known from LPN, even with extremely low noise.
MIT Department
Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science
Massachusetts Institute of Technology. Computer Science and Artificial Intelligence Laboratory
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Creative Commons Attribution-Noncommercial-Share Alike
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DOI of Published Version
https://doi.org/10.1007/978-3-319-78381-9_20
