### Universally Composable Secure Computation with Corrupted Tokens

Nishanth Chandran, Wutichai Chongchitmate, Rafail Ostrovsky, and Ivan Visconti

##### Abstract

We introduce the \emph{corrupted token model}. This model generalizes the \emph{tamper-proof token model} proposed by Katz (EUROCRYPT '07) relaxing the trust assumption on the honest behavior of tokens. Our model is motivated by the real-world practice of outsourcing hardware production to possibly corrupted manufacturers. We capture the malicious behavior of token manufacturers by allowing the adversary to corrupt the tokens of honest players at the time of their creation. We show that under minimal complexity assumptions, i.e., the existence of one-way functions, it is possible to UC-securely realize (a variant of) the tamper-proof token functionality of Katz in the corrupted token model with $n$ stateless tokens assuming that the adversary corrupts at most $n-1$ of them (for any positive $n$). We then apply this result to existing multi-party protocols in Katz's model to achieve UC-secure MPC in the corrupted token model assuming only the existence of one-way functions. Finally, we show how to obtain the above results using tokens of small size that take only short inputs. The technique in this result can also be used to improve the assumption of UC-secure hardware obfuscation recently proposed by Nayak et al. (NDSS '17). While their construction requires the existence of collision-resistant hash functions, we can obtain the same result from only one-way functions. Moreover using our main result we can improve the trust assumption on the tokens as well.

Available format(s)
Category
Cryptographic protocols
Publication info
Preprint. MINOR revision.
Keywords
tamper-proof tokencorruptiblesetup assumptionUC securityMPC
Contact author(s)
wutichai ch @ chula ac th
History
2018-10-07: revised
See all versions
Short URL
https://ia.cr/2017/1092

CC BY

BibTeX

@misc{cryptoeprint:2017/1092,
author = {Nishanth Chandran and Wutichai Chongchitmate and Rafail Ostrovsky and Ivan Visconti},
title = {Universally Composable Secure Computation with Corrupted Tokens},
howpublished = {Cryptology ePrint Archive, Paper 2017/1092},
year = {2017},
note = {\url{https://eprint.iacr.org/2017/1092}},
url = {https://eprint.iacr.org/2017/1092}
}

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