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LWE / Small secret · rescaled primal

Lattice Decoding Attacks on Binary LWE

Shi Bai · Steven D. Galbraith

ACISP 2014

PublishedSource checked
Time bound
Treduce(d+1,δ), with d=m+n and δd≲(qmσn)1/d/(σ√(2πe))
Space bound
Depends on the reduction/enumeration subroutine.
Source / version date
21 Feb 2017
Cost scale
Parameter-dependent time and space expressions
Parameters
Fix n,m,q and Gaussian error standard deviation σ; ternary secret for the displayed determinant; d=m+n.
Error distribution
Independent discrete Gaussian error, standard deviation σ; no fixed universal σ(n) is assumed.
Secret distribution
Uniform ternary {−1,0,1}^n for displayed formula; binary {0,1}^n uses (2σ)^n determinant factor and recentering.
Sample budget
m available samples; source may discard rows. For ternary scaling, optimized d≈√(n(log₂q−log₂σ)/log₂δ) if allowed by m.
Objective
Recover small secret and error.
Cost model
ISIS embedding, rescaling, then CVP/uSVP decoding; displayed gap uses the Gaussian heuristic.
Assumptions
Random-lattice Gaussian heuristic and reduction-success model.
Success guarantee
Model-dependent recovery; experiments do not establish an arbitrary-lattice guarantee.

Assumptions and source notes

The ternary-secret scaling increases determinant by σ^n. For binary secrets the source uses scaling 2σ plus recentering. First posted December 2013 and published ACISP 2014; this record conservatively dates the fully checked revised PDF.

Source location

§§6.1–6.2, pp. 10–11, determinant scaling, gap discussion, Lemma 1 and Eq. (6)
Version: Full ePrint version last revised 21 February 2017; first ePrint 16 December 2013; ACISP 2014

Selected earlier references

Selected sources cited by this paper.

  1. Better Key Sizes (and Attacks) for LWE-Based Encryption

    Richard Lindner · Chris Peikert · 2011

    Uses the earlier lattice decoding analysis as a baseline before exploiting small secrets. §4 standard lattice attack and reference [15] in the checked full ePrint

  2. On the Efficacy of Solving LWE by Reduction to Unique-SVP

    Martin R. Albrecht · Robert Fitzpatrick · Florian Göpfert · 2014

    Uses prior BDD-to-uSVP embedding and its practical success model. §4.3 embedding discussion; reference [2] in ACISP 2014 edition

  3. New Algorithms for Learning in Presence of Errors

    Sanjeev Arora · Rong Ge · 2011

    Explains why very small errors are only meaningful with an explicit restricted sample budget. §3 related work; reference [4] in full ePrint

  4. Lattice-based Cryptography

    Daniele Micciancio · Oded Regev · 2009

    Uses earlier random q-ary lattice security and distinguishing analysis as context. §4 and references; ACISP 2014 reference [20]

Primary source ↗

@misc{bai-galbraith2013-binary-lwe,
  author = {Shi Bai and Steven D. Galbraith},
  title = {{Lattice Decoding Attacks on Binary LWE}},
  year = {2014},
  url = {https://eprint.iacr.org/2013/839},
  keywords = {LWE, algorithmic complexity, historical literature},
  cr_date = {2013-12-16},
  cr_date_precision = {day},
  cr_status = {published},
  cr_venue = {ACISP 2014, LNCS 8544, pp. 322–337; DOI 10.1007/978-3-319-08344-5_21},
  cr_author_ids = {shi-bai; steven-d-galbraith},
  note = {ACISP 2014, LNCS 8544, pp. 322–337; DOI 10.1007/978-3-319-08344-5_21}
}