Cryptology ePrint Archive: Report 2015/889

Which Ring Based Somewhat Homomorphic Encryption Scheme is Best?

Anamaria Costache and Nigel P. Smart

Abstract: The purpose of this paper is to compare side-by-side the NTRU and BGV schemes in their non-scale invariant (messages in the lower bits), and their scale invariant (message in the upper bits) forms. The scale invariant versions are often called the FV and YASHE schemes. As an additional optimization, we also investigate the affect of modulus reduction on the scale-invariant schemes. We compare the schemes using the ``average case'' noise analysis presented by Gentry et al. In addition we unify notation and techniques so as to show commonalities between the schemes. We find that the BGV scheme appears to be more efficient for large plaintext moduli, whilst YASHE seems more efficient for small plaintext moduli (although the benefit is not as great as one would have expected).

Category / Keywords: public-key cryptography /

Original Publication (with major differences): CT-RSA 2016

Date: received 14 Sep 2015, last revised 23 Nov 2015

Contact author: anamaria costache at bristol ac uk,nigel@cs bris ac uk

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Version: 20151123:111005 (All versions of this report)

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