Paper 2008/533

Collusion-Free Multiparty Computation in the Mediated Model

Jonathan Katz and Yehuda Lindell

Abstract

Collusion-free protocols prevent subliminal communication (i.e., covert channels) between parties running the protocol. In the standard communication model (and assuming the existence of one-way functions), protocols satisfying any reasonable degree of privacy cannot be collusion-free. To circumvent this impossibility result, Alwen et al. recently suggested the mediated model where all communication passes through a mediator; the goal is to design protocols where collusion-freeness is guaranteed as long as the mediator is honest, while standard security guarantees continue to hold if the mediator is dishonest. In this model, they gave constructions of collusion-free protocols for commitments and zero-knowledge proofs in the two-party setting. We strengthen the definition of Alwen et al. in several ways, and resolve the key open questions in this area by showing a collusion-free protocol (in the mediated model) for computing any multi-party functionality.

Metadata
Available format(s)
PDF
Category
Cryptographic protocols
Publication info
Published elsewhere. Unknown where it was published
Keywords
secure computation
Contact author(s)
jkatz @ cs umd edu
History
2008-12-19: received
Short URL
https://ia.cr/2008/533
License
Creative Commons Attribution
CC BY

BibTeX

@misc{cryptoeprint:2008/533,
      author = {Jonathan Katz and Yehuda Lindell},
      title = {Collusion-Free Multiparty Computation in the Mediated Model},
      howpublished = {Cryptology ePrint Archive, Paper 2008/533},
      year = {2008},
      note = {\url{https://eprint.iacr.org/2008/533}},
      url = {https://eprint.iacr.org/2008/533}
}
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