Cryptology ePrint Archive: Report 2021/1626

A Successful Subfield Lattice Attack on a Fully Homomorphic Encryption Scheme

Martha Norberg Hovd

Abstract: We present the application of a known subfield lattice attack on a fully homomorphic encryption scheme based on NTRU. We show that the scheme is vulnerable to the attack due to a particular parameter having to satisfy a derived lower bound. We also show that, due to the structure of the scheme, the attack is successful in all practical instantiations of the scheme.

Category / Keywords: public-key cryptography / Fully homomorphic encryption, lattices, NTRU

Original Publication (with minor differences): Norwegian Information Security Conference

Date: received 13 Dec 2021

Contact author: martha at simula no

Available format(s): PDF | BibTeX Citation

Version: 20211217:141916 (All versions of this report)

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