Accelerating Homomorphic Encryption using Approximate Computing Techniques

Shabnam Khanna*, Ciara Rafferty*

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

This research proposes approximate computing techniques to accelerate homomorphic encryption (HE). In
particular, the CKKS encryption scheme for approximate numbers is targeted. There is a requirement for HE in
services dealing with confidential data, however current constructions are not efficient enough for real-time
applications. A homomorphic encryption scheme which uses approximate arithmetic (showing faster results
than previous HE schemes) already exists, the CKKS scheme, and this research applies a variation of the
approximate computing techniques of task skipping and depth reduction (derived from loop perforation) to
determine whether further approximating the functions evaluated using CKKS scheme can have a positive
impact on performance of homomorphic evaluation. This is demonstrated via the evaluation of the logistic
and exponential functions that this is possible, showing positive results. The speed up in running time for
HE with task skipping is between 12.1% and 45.5%, depth reduction gives 35-45.5% speed-up with a small
error difference than task skipping alone. The combination of both techniques corresponds to a halving of
the running time, at the cost of increased error. This novel approach to further approximate homomorphic
encryption shows that it is possible for certain functions, where running time is of paramount importance, that
further approximations can be made with a lower-impacting greater error.
Original languageEnglish
Title of host publicationThe 17th International Conference on Security and Cryptography - SECRYPT 2020
PublisherSpringer
Publication statusAccepted - 15 Apr 2020
EventThe 17th International Conference on Security and Cryptography - SECRYPT 2020 - Lieusant, Paris, Italy
Duration: 08 Jul 202010 Jul 2020
http://www.secrypt.icete.org/Home.aspx

Conference

ConferenceThe 17th International Conference on Security and Cryptography - SECRYPT 2020
Abbreviated titleSECRYPT 2020
CountryItaly
CityParis
Period08/07/202010/07/2020
Internet address

Keywords

  • Homomorphic Encryption
  • Approximate Computing
  • Task skipping
  • depth reduction
  • loop perforation

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  • Cite this

    Khanna, S., & Rafferty, C. (Accepted/In press). Accelerating Homomorphic Encryption using Approximate Computing Techniques. In The 17th International Conference on Security and Cryptography - SECRYPT 2020 Springer.