TY - JOUR

T1 - ON PAIRWISE GAUSSIAN BASES AND LLL ALGORITHM FOR THREE DIMENSIONAL LATTICES

AU - Kim, Kitae

AU - Lee, Hyang Sook

AU - Lim, Seongan

AU - Park, Jeongeun

AU - Yie, Ikkwon

N1 - Funding Information:
Acknowledgments. Hyang-Sook Lee was supported by the National Research Foundation of Korea(NRF) grant funded by the Korea government(MSIT) (No. NRF-2021R1A2C1094821) and partially supported by the Basic Science Research Program through the NRF funded by the Ministry of Education (Grant No. 2019R1A6A1A11051177). Seongan Lim was supported by the NRF of Korea (Grant Number: 2016R1D1A1B01008562).
Publisher Copyright:
© 2022 Korean Mathematical Society.

PY - 2022/11

Y1 - 2022/11

N2 - For two dimensional lattices, a Gaussian basis achieves all two successive minima. For dimension larger than two, constructing a pairwise Gaussian basis is useful to compute short vectors of the lattice. For three dimensional lattices, Semaev showed that one can convert a pairwise Gaussian basis to a basis achieving all three successive minima by one simple reduction. A pairwise Gaussian basis can be obtained from a given basis by executing Gauss algorithm for each pair of basis vectors repeatedly until it returns a pairwise Gaussian basis. In this article, we prove a necessary and sufficient condition for a pairwise Gaussian basis to achieve the first k successive minima for three dimensional lattices for each k ∈ {1, 2, 3} by modifying Semaev’s condition. Our condition directly checks whether a pairwise Gaussian basis contains the first k shortest independent vectors for three dimensional lattices. LLL is the most basic lattice basis reduction algorithm and we study how to use LLL to compute a pairwise Gaussian basis. For δ ≥ 0.9, we prove that LLL(δ) with an additional simple reduction turns any basis for a three dimensional lattice into a pairwise SV-reduced basis. By using this, we convert an LLL reduced basis to a pairwise Gaussian basis in a few simple reductions. Our result suggests that the LLL algorithm is quite effective to compute a basis with all three successive minima for three dimensional lattices.

AB - For two dimensional lattices, a Gaussian basis achieves all two successive minima. For dimension larger than two, constructing a pairwise Gaussian basis is useful to compute short vectors of the lattice. For three dimensional lattices, Semaev showed that one can convert a pairwise Gaussian basis to a basis achieving all three successive minima by one simple reduction. A pairwise Gaussian basis can be obtained from a given basis by executing Gauss algorithm for each pair of basis vectors repeatedly until it returns a pairwise Gaussian basis. In this article, we prove a necessary and sufficient condition for a pairwise Gaussian basis to achieve the first k successive minima for three dimensional lattices for each k ∈ {1, 2, 3} by modifying Semaev’s condition. Our condition directly checks whether a pairwise Gaussian basis contains the first k shortest independent vectors for three dimensional lattices. LLL is the most basic lattice basis reduction algorithm and we study how to use LLL to compute a pairwise Gaussian basis. For δ ≥ 0.9, we prove that LLL(δ) with an additional simple reduction turns any basis for a three dimensional lattice into a pairwise SV-reduced basis. By using this, we convert an LLL reduced basis to a pairwise Gaussian basis in a few simple reductions. Our result suggests that the LLL algorithm is quite effective to compute a basis with all three successive minima for three dimensional lattices.

KW - Lattice

KW - lattice basis reduction

KW - LLL

KW - pairwise-Gaussian basis

UR - http://www.scopus.com/inward/record.url?scp=85141433365&partnerID=8YFLogxK

U2 - 10.4134/JKMS.j210496

DO - 10.4134/JKMS.j210496

M3 - Article

AN - SCOPUS:85141433365

SN - 0304-9914

VL - 59

SP - 1047

EP - 1065

JO - Journal of the Korean Mathematical Society

JF - Journal of the Korean Mathematical Society

IS - 6

ER -