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.
Category / Keywords: cryptographic protocols / tamper-proof token, corruptible, setup assumption, UC security, MPC Date: received 7 Nov 2017, last revised 7 Oct 2018 Contact author: wutichai ch at chula ac th Available format(s): PDF | BibTeX Citation Version: 20181007:085746 (All versions of this report) Short URL: ia.cr/2017/1092