Title
Efficient FHE Radix-2 Arithmetic Operations Based on Redundant Encoding
Abstract
Fully homomorphic encryption (FHE) is a novel encryption method that can perform operations on encrypted data. The performance of applications based on FHE is still low due to the high computational complexity of operations on the ciphertext. This article combines the characteristics of FHE and the redundant encoding method to achieve faster radix-2 arithmetic operations in BGV-like schemes. First, a ciphertext integer addition with multiplicative depth two, namely, redundant carry-free addition (RCFA), is proposed by applying the carry-free feature of the redundant encoding method. This addition is <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$7.207\times $ </tex-math></inline-formula> faster and uses 15.0% of the occupied memory at 512 bits compared with the nonredundant method. After utilizing the single-instruction–multiple-data (SIMD) technique, RCFA with SIMD further improves the efficiency by <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$3903\times $ </tex-math></inline-formula> at 512 bits compared with the nonredundant SIMD method. Its ciphertext size and occupied memory are only 34.59% and 1.6% those of the nonredundant SIMD method. Second, to achieve efficient ciphertext multiplications, redundant multiplication (RM) of dual SIMD data (RMDS) and RM of SIMD and non-SIMD data (RMSNS) methods are proposed; they obtain speedups of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$65.6\times $ </tex-math></inline-formula> and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$631.0\times $ </tex-math></inline-formula> , respectively, at 32 bits compared with the nonredundant implementations. Finally, SHA-256 is implemented to validate the efficiency of the proposed arithmetic operations. Compared with the nonredundant SIMD method, this article obtains a speedup of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$4.34\times $ </tex-math></inline-formula> .
Year
DOI
Venue
2022
10.1109/TCAD.2021.3101410
IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems
Keywords
DocType
Volume
BGV,ciphertext arithmetic operation,fully homomorphic encryption (FHE),redundant encoding
Journal
41
Issue
ISSN
Citations 
7
0278-0070
0
PageRank 
References 
Authors
0.34
22
8
Name
Order
Citations
PageRank
Zongsheng Hou100.68
Neng Zhang200.34
Bohan Yang373.22
Hanning Wang400.34
Min Zhu502.37
shouyi yin657999.95
Shaojun Wei7555102.32
leibo liu8816116.95