Paper 2007/332
Universally Composable Multiparty Computation with Partially Isolated Parties
Ivan Damgaard, Jesper Buus Nielsen, and Daniel Wichs
Abstract
It is well known that universally composable multiparty computation cannot, in general, be achieved in the standard model without setup assumptions when the adversary can corrupt an arbitrary number of players. One way to get around this problem is by having a \emph{trusted third party} generate some global setup such as a \emph{common reference string (CRS)} or a \emph{public key infrastructure (PKI)}. The recent work of Katz shows that we may instead rely on physical assumptions, and in particular \emph{tamperproof hardware tokens}. In this paper, we consider a similar but \emph{strictly weaker} physical assumption. We assume that a player (Alice) can \emph{partially isolate} another player (Bob) for a brief portion of the computation and prevent Bob from communicating more than some limited number of bits with the environment. For example, isolation might be achieved by asking Bob to put his functionality on a tamperproof hardware token and assuming that Alice can prevent this token from communicating to the outside world. Alternatively, Alice may interact with Bob directly but in a special office which she administers and where there are no highbandwidth communication channels to the outside world. We show that, under \emph{standard} cryptographic assumptions, such physical setup can be used to UCrealize any two party and multiparty computation in the presence of an active and \emph{adaptive} adversary corrupting any number of players. We also consider an alternative scenario, in which there are some trusted third parties but no single such party is trusted by all of the players. This compromise allows us to significantly limit the use of the physical setup and hence might be preferred in practice.
Metadata
 Available format(s)
 PDF PS
 Category
 Cryptographic protocols
 Publication info
 Published elsewhere. Full version of TCC 2009 paper.
 Keywords
 multiparty computationuniversal composabilityphysical assumptions
 Contact author(s)
 danwichs @ gmail com
 History
 20081214: last of 3 revisions
 20070822: received
 See all versions
 Short URL
 https://ia.cr/2007/332
 License

CC BY
BibTeX
@misc{cryptoeprint:2007/332, author = {Ivan Damgaard and Jesper Buus Nielsen and Daniel Wichs}, title = {Universally Composable Multiparty Computation with Partially Isolated Parties}, howpublished = {Cryptology ePrint Archive, Paper 2007/332}, year = {2007}, note = {\url{https://eprint.iacr.org/2007/332}}, url = {https://eprint.iacr.org/2007/332} }