Cryptology ePrint Archive: Report 2017/978

New Constructions of Identity-Based and Key-Dependent Message Secure Encryption Schemes

Nico Döttling and Sanjam Garg and Mohammad Hajiabadi and Daniel Masny

Abstract: Recently, Döttling and Garg (CRYPTO 2017) showed how to build identity-based encryption (IBE) from a novel primitive termed Chameleon Encryption, which can, in turn, be realized from simple number theoretic hardness assumptions such as the computational Diffie-Hellman assumption (in groups without pairings) or the factoring assumption. In a follow-up work (TCC 2017), the same authors showed that IBE can also be constructed from a slightly weaker primitive called One-Time Signatures with Encryption (OTSE).

In this work, we show that OTSE can be instantiated from hard learning problems such as the Learning With Errors (LWE) and the Learning Parity with Noise (LPN) problems. This immediately yields the first IBE construction from the LPN problem and a construction based on a weaker LWE assumption compared to previous works.

Finally, we show that the notion of one-time signatures with encryption is also useful for the construction of key-dependent-message (KDM) secure public-key encryption. In particular, our results imply that a KDM-secure public key encryption can be constructed from any KDM-secure secret-key encryption scheme and any public-key encryption scheme.

Category / Keywords: KDM security, IBE, LPN, LWE

Original Publication (in the same form): IACR-PKC-2018

Date: received 3 Oct 2017, last revised 9 Jan 2018

Contact author: daniel masny at berkeley edu, sanjamg@berkeley edu, nico doettling@gmail com, mdhajiabadi@berkeley edu

Available format(s): PDF | BibTeX Citation

Version: 20180109:210445 (All versions of this report)

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