License: Creative Commons Attribution 3.0 Unported license (CC BY 3.0)
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DOI: 10.4230/LIPIcs.ITC.2020.7
URN: urn:nbn:de:0030-drops-121124
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Lin, Fuchun ; Cheraghchi, Mahdi ; Guruswami, Venkatesan ; Safavi-Naini, Reihaneh ; Wang, Huaxiong

Leakage-Resilient Secret Sharing in Non-Compartmentalized Models

LIPIcs-ITC-2020-7.pdf (0.6 MB)


Leakage-resilient secret sharing has mostly been studied in the compartmentalized models, where a leakage oracle can arbitrarily leak bounded number of bits from all shares, provided that the oracle only has access to a bounded number of shares when the leakage is taking place. We start a systematic study of leakage-resilient secret sharing against global leakage, where the leakage oracle can access the full set of shares simultaneously, but the access is restricted to a special class of leakage functions. More concretely, the adversary can corrupt several players and obtain their shares, as well as applying a leakage function from a specific class to the full share vector. We explicitly construct such leakage-resilient secret sharing with respect to affine leakage functions and low-degree multi-variate polynomial leakage functions, respectively. For affine leakage functions, we obtain schemes with threshold access structure that are leakage-resilient as long as there is a substantial difference between the total amount of information obtained by the adversary, through corrupting individual players and leaking from the full share vector, and the amount that the reconstruction algorithm requires for reconstructing the secret. Furthermore, if we assume the adversary is non-adaptive, we can even make the secret length asymptotically equal to the difference, as the share length grows. Specifically, we have a threshold scheme with parameters similar to Shamir’s scheme and is leakage-resilient against affine leakage. For multi-variate polynomial leakage functions with degree bigger than one, our constructions here only yield ramp schemes that are leakage-resilient against such leakage. Finally, as a result of independent interest, we show that our approach to leakage-resilient secret sharing also yields a competitive scheme compared with the state-of-the-art construction in the compartmentalized models.

BibTeX - Entry

  author =	{Fuchun Lin and Mahdi Cheraghchi and Venkatesan Guruswami and Reihaneh Safavi-Naini and Huaxiong Wang},
  title =	{{Leakage-Resilient Secret Sharing in Non-Compartmentalized Models}},
  booktitle =	{1st Conference on Information-Theoretic Cryptography (ITC 2020)},
  pages =	{7:1--7:24},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-151-1},
  ISSN =	{1868-8969},
  year =	{2020},
  volume =	{163},
  editor =	{Yael Tauman Kalai and Adam D. Smith and Daniel Wichs},
  publisher =	{Schloss Dagstuhl--Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{},
  URN =		{urn:nbn:de:0030-drops-121124},
  doi =		{10.4230/LIPIcs.ITC.2020.7},
  annote =	{Keywords: Leakage-resilient cryptography, Secret sharing scheme, Randomness extractor}

Keywords: Leakage-resilient cryptography, Secret sharing scheme, Randomness extractor
Collection: 1st Conference on Information-Theoretic Cryptography (ITC 2020)
Issue Date: 2020
Date of publication: 04.06.2020

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