Cryptology ePrint Archive: Report 2022/095

Spatial Encryption Revisited: From Delegatable Multiple Inner Product Encryption and More

Huy Quoc Le and Dung Hoang Duong and Willy Susilo and Josef Pieprzyk

Abstract: Spatial Encryption (SE), which involves encryption and decryption with affine/vector objects, was introduced by Boneh and Hamburg at Asiacrypt 2008. Since the introduction, SE has been shown as a versatile and elegant tool for implementing many other important primitives such as (Hierarchical) Identity-based Encryption ((H)IBE), Broadcast (H)IBE, Attribute-based Encryption, Forward-secure cryptosystems.

In this paper, we revisit SE toward a more compact SE in the lattice setting. In doing that, we introduce a novel primitive called Delegatable Multiple Inner Product Encryption (DMIPE), which is a delegatable generalization of Inner Product Encryption (IPE) but different from the Hierarchical IPE (HIPE) (Okamoto and Takashima at Asiacrypt 2009). We point out that DMIPE and SE are equivalent in the sense that there are security-preserving conversions between them. As a proof of concept, we then successfully instantiate a concrete DMIPE construction relying on the hardness of the decisional learning with errors problem. The DMIPE design in turn implies a more compact lattice-based SE in terms of sizes, in comparison with SEs converted from HIPE (e.g., Xagawa’s HIPE at PKC 2013) using the framework by Chen at al. (Designs, Codes, and Cryptography, 2014). Furthermore, we show that SE can also be used to implement the Allow-/Deny-list encryption, which subsumes, e.g., puncturable encryption (Green and Miers at IEEE S&P 2015) among others

Category / Keywords: cryptographic protocols / spatial encryption, learning with errors, inner product encryption, delegatable multiple inner product encryption, hierarchical inner product encryption, allow-/deny-list encryption, lattice evaluation, lattice trapdoors

Date: received 26 Jan 2022

Contact author: huyle84 at gmail com

Available format(s): PDF | BibTeX Citation

Version: 20220131:074329 (All versions of this report)

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