Paper 2019/1035 Original: eprint.iacr.org/2019/1035 ↗

An LLL Algorithm for Module Lattices

Changmin Lee
Alice Pellet-Mary
Damien Stehlé
Alexandre Wallet
Abstract

The LLL algorithm takes as input a basis of a Euclidean lattice, and, within a polynomial number of operations, it outputs another basis of the same lattice but consisting of rather short vectors. We provide a generalization to R-modules contained in K^n for arbitrary number fields K and dimension n, with R denoting the ring of integers of K. Concretely, we introduce an algorithm that efficiently finds short vectors in rank-n modules when given access to an oracle that finds short vectors in rank-2 modules, and an algorithm that efficiently finds short vectors in rank-2 modules given access to a Closest Vector Problem oracle for a lattice that depends only on K. The second algorithm relies on quantum computations and its analysis is heuristic. In the special case of free modules, we propose a dequantized version of this algorithm.

Metadata
Available format(s)
PDF
Category
Foundations
Publication info
Preprint.
History
2020-06-19: last updated
2019-09-16: published
Short URL
https://ia.cr/2019/1035
License
https://creativecommons.org/licenses/by/4.0/

BibTeX

@misc{cryptoeprint:2019/1035,
      author = {Changmin Lee and Alice Pellet-Mary and Damien Stehlé and Alexandre Wallet},
      title = {An LLL Algorithm for Module Lattices},
      howpublished = {Cryptology {ePrint} Archive, Paper 2019/1035},
      year = {2019},
      url = {https://eprint.iacr.org/2019/1035}
}
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