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LWE / Decision · binary secret and error · n samples

An Improved BKW Algorithm for LWE with Applications to Cryptography and Lattices

Paul Kirchner · Pierre-Alain Fouque

Crypto 2015

PublishedSource checked
Time bound
2(ln(2)/2+o(1)) n/log₂ log₂ n
Space bound
Not separately normalized
Source / version date
29 Jun 2015
Cost scale
2c n / log₂ log₂ n + o(n/log₂ log₂ n)
Input samples
n original equations
Model / assumptions
Uniform binary secret and errors; prime modulus q≈n²
Exact coefficient / bound
ln(2)/2 on the n/log₂log₂n scale

Assumptions and source notes

Decision bound for binary secret/error, q≈n², m=n. The corollary gap is Θ(log n), satisfying HKM’s stronger amplification condition.

Source location

Abstract; §5.2, Definition 11 and Corollary 6
Version: arXiv:1506.02717v4, 29 June 2015

Selected earlier references

Selected sources cited by this paper.

  1. On the Complexity of the BKW Algorithm on LWE

    Martin R. Albrecht · Carlos Cid · Jean-Charles Faugère · Robert Fitzpatrick · Ludovic Perret · 2015

    Discusses the original LWE adaptation and its noise-growth analysis. §3.1, reference [4]; after Corollary 1

  2. Lazy Modulus Switching for the BKW Algorithm on LWE

    Martin R. Albrecht · Jean-Charles Faugère · Robert Fitzpatrick · Ludovic Perret · 2014

    Generalizes the lazy-modulus-switching viewpoint using stage-dependent quantization. §3.1, reference [5]

  3. An Improved LPN Algorithm

    Éric Levieil · Pierre-Alain Fouque · 2006

    Lists an earlier BKW improvement for the binary case. Introduction, reference [33]

  4. Noise-Tolerant Learning, the Parity Problem, and the Statistical Query Model

    Avrim Blum · Adam Kalai · Hal Wasserman · 2000

    Starts from the original blockwise Gaussian-elimination algorithm. §3.1, reference [12]

Primary source ↗

@inproceedings{paper-e014be9a6925,
  author = {Paul Kirchner and Pierre-Alain Fouque},
  title = {{An Improved BKW Algorithm for LWE with Applications to Cryptography and Lattices}},
  booktitle = {Advances in Cryptology -- CRYPTO 2015},
  year = {2015},
  volume = {9215},
  pages = {43--62},
  publisher = {Springer},
  doi = {10.1007/978-3-662-47989-6_3},
  url = {https://arxiv.org/abs/1506.02717},
  cr_date = {2015-06-08},
  cr_status = {published},
  cr_venue = {Advances in Cryptology -- CRYPTO 2015},
  cr_author_ids = {paul-kirchner; pierre-alain-fouque},
  series = {Lecture Notes in Computer Science}
}