Accelerating ltv based homomorphic encryption in reconfigurable hardware

Yarkın Doröz, Erdinç Öztürk, Erkay Savaş, Berk Sunar

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

22 Scopus citations


After being introduced in 2009, the first fully homomorphic encryption (FHE) scheme has created significant excitement in academia and industry. Despite rapid advances in the last 6 years, FHE schemes are still not ready for deployment due to an efficiency bottleneck. Here we introduce a custom hardware accelerator optimized for a class of reconfigurable logic to bring LTV based somewhat homomorphic encryption (SWHE) schemes one step closer to deployment in real-life applications. The accelerator we present is connected via a fast PCIe interface to a CPU platform to provide homomorphic evaluation services to any application that needs to support blinded computations. Specifically we introduce a number theoretical transform based multiplier architecture capable of efficiently handling very large polynomials. When synthesized for the Xilinx Virtex 7 family the presented architecture can compute the product of large polynomials in under 6. 25 msec making it the fastest multiplier design of its kind currently available in the literature and is more than 102 times faster than a software implementation. Using this multiplier we can compute a relinearization operation in 526 msec. When used as an accelerator, for instance, to evaluate the AES block cipher, we estimate a per block homomorphic evaluation performance of 442 msec yielding performance gains of 28. 5 and 17 times over similar CPU and GPU implementations, respectively.

Original languageEnglish (US)
Title of host publicationCryptographic Hardware and Embedded Systems - 17th International Workshop, CHES 2015, Proceedings
EditorsTim Güneysu, Helena Handschuh
PublisherSpringer Verlag
Number of pages20
ISBN (Print)9783662483237
StatePublished - 2015
Externally publishedYes
EventInternational Workshop on Cryptographic Hardware and Embedded Systems, CHES 2015 - Saint-Malo, France
Duration: Sep 13 2015Sep 16 2015

Publication series

NameLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
ISSN (Print)0302-9743
ISSN (Electronic)1611-3349


OtherInternational Workshop on Cryptographic Hardware and Embedded Systems, CHES 2015

All Science Journal Classification (ASJC) codes

  • Theoretical Computer Science
  • General Computer Science


  • FPGA
  • NTT multiplication
  • Somewhat homomorphic encryption


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