Our main technical tool is a new primitive that we call {\em interactive locking}, an efficient realization of an unconditionally secure commitment scheme in the interactive PCP model. We implement interactive locking by adapting previous constructions of {\em interactive hashing} protocols to our setting, and also provide a direct construction which uses a minimal amount of interaction and improves over our interactive hashing based constructions.
Finally, we apply the above results towards showing the feasibility of basing unconditional cryptography on {\em stateless} tamper-proof hardware tokens, and obtain the following results:
*) We show that if tokens can be used to encapsulate other tokens, then there exist unconditional and statistically secure (in fact, UC secure) protocols for general secure computation. *) Even if token encapsulation is not possible, there are unconditional and statistically secure commitment protocols and zero-knowledge proofs for $NP$. *) Finally, if token encapsulation is not possible, then no protocol can realize statistically secure oblivious transfer.
Category / Keywords: foundations / Cryptography, Statistical Security, Zero Knowledge, Interactive Proof, Interactive PCP, Commitment Scheme, Oblivious Transfer, Interactive Hashing Date: received 18 Feb 2010 Contact author: mahmoody at gmail com Available format(s): PDF | BibTeX Citation Version: 20100222:130924 (All versions of this report) Short URL: ia.cr/2010/089 Discussion forum: Show discussion | Start new discussion