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Paper: Combining Computational and Information-Theoretic Security in Multi-Party Computation

Authors:
Christoph Lucas
Dominik Raub
Ueli Maurer
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URL: http://eprint.iacr.org/2009/009
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Abstract: Most protocols for multi-party computation (MPC) are secure either against information-theoretic (IT) or against computationally bounded adversaries. In this work, we bring together the best of both worlds: For any robustness parameter $\rob<\frac{n}{2}$ we obtain one MPC protocol that is simultaneously IT secure with robustness for up to $t\leq\rob$ actively corrupted parties, IT secure with fairness (no robustness) for up to $t<\frac{n}{2}$ and computationally secure with agreement on abort (no fairness) for up to $t<n-\rob$. Our construction is secure in the universal composability (UC) framework, and achieves the bounds of Ishai et al. [CRYPTO'06], Katz [STOC'07], and Cleve [STOC'86] on trade-offs between robustness and privacy, and on fairness. For example, for the special case $\rob=0$ our protocol simultaneously achieves non-robust MPC for up to $t<n$ corrupted parties in the computational setting (like Goldreich et al. [STOC'87]) while providing security with fairness in the IT setting for up to $t<\frac{n}{2}$ corrupted parties (like Rabin and Ben-Or [STOC'89] though without robustness).
BibTeX
@misc{eprint-2009-18214,
  title={Combining Computational and Information-Theoretic Security in Multi-Party Computation},
  booktitle={IACR Eprint archive},
  keywords={cryptographic protocols / multi-party computation, information-theoretic security, computational security, hybrid security, robustness, fairness, agreement on abort, universal composability},
  url={http://eprint.iacr.org/2009/009},
  note={ d.raub@inf.ethz.ch 14249 received 5 Jan 2009},
  author={Christoph Lucas and Dominik Raub and Ueli Maurer},
  year=2009
}