Title
When NTT Meets Karatsuba: Preprocess-then-NTT Technique Revisited
Abstract
The Number Theoretic Transform (NTT) technique is widely used to implement cryptographic schemes based on the Ring Learning With Errors problem(RLWE), since it provides efficient algorithm for multiplication of polynomials over the finite field. However, the module in NTT must be big enough such that the finite field has some special root of unity, which makes the corresponding schemes a bit less efficient. At Inscrypt 2018, Zhou et al. proposed a technique called Preprocess-then-NTT to relax the constraint for the modulus while keeping NTT work, at the cost of time complexity. In this paper, we improve the Preprocess-then-NTT technique by mixing it with Karatsuba multiplication such that the time complexity is better than the original NTT algorithm asymptotically. The claim was also verified in our experiments. As a result, our new algorithm not only relaxes the constraint for modulus but also improves efficiency in practice. In addition, we also present some advantages and applications of our new algorithm.
Year
DOI
Venue
2021
10.1007/978-3-030-88052-1_15
INFORMATION AND COMMUNICATIONS SECURITY (ICICS 2021), PT II
Keywords
DocType
Volume
NTT, Ring Learning With Errors, Polynomial, Multiplication
Conference
12919
ISSN
Citations 
PageRank 
0302-9743
0
0.34
References 
Authors
0
3
Name
Order
Citations
PageRank
Yiming Zhu100.68
Zhen Liu200.34
Yanbin Pan33513.29