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Physically Uncloneable Functions (PUFs) [28] are noisy physical sources of randomness. As such, they are naturally appealing for cryptographic applications, and have caught the interest of both the-oreticians and practitioners. A major step towards understanding and securely using PUFs was recently taken in [Crypto 2011] where Brzuska, Fischlin, Schröder(More)
In this work, we study simultaneously resettable arguments of knowledge. As our main result, we show a construction of a constant-round simultaneously resettable witness-indistinguishable argument of knowledge (simresWIAoK, for short) for any NP language. We also show two applications of simresWIAoK: the first constant-round simultaneously resettable(More)
We present a constant-round unconditional black-box compiler, that transforms any ideal straight-line extractable commitment scheme, into an extractable and equivocal commitment scheme, therefore yielding to UC-security [Can01]. We exemplify the usefulness of our compiler providing two (constant-round) instantiations of ideal straight-line extractable(More)
Contrary to prior belief, we show that there exist commitment, zero-knowledge and general function evaluation protocols with universally composable security, in a model where all parties and all protocols have access to a single, global, random oracle and no other trusted setup. This model provides significantly stronger composable security guarantees than(More)
Yao's garbled circuit construction is a very fundamental result in cryptography and recent efficiency optimizations have brought it much closer to practice. However these constructions work only for circuits and garbling a RAM program involves the inefficient process of first converting it into a circuit. Towards the goal of avoiding this inefficiency, Lu(More)
In [DNRS99, DNRS03], Dwork et al. opened the fundamental question of existence of commitment schemes that are secure against selective opening attacks (SOA, for short). In [BHY09] Bellare, Hofheinz, and Yilek, and Hofheinz in [Hof11] solved this problem positively by presenting a scheme which is based on non-black-box use of a one-way permutation and which(More)
In this paper we revisit previous work in the BPK model and point out subtle problems concerning security proofs of concurrent and resettable zero knowledge (cZK and rZK, for short). Our analysis shows that the cZK and rZK simulations proposed for previous (in particular all round-optimal) protocols are distinguishable from real executions. Therefore some(More)
Motivated by theoretical and practical interest, the challenging task of designing cryptographic protocols having only black-box access to primitives has generated various breakthroughs in the last decade. Despite such positive results, even though nowadays we know black-box constructions for secure two-party and multi-party computation even in constant(More)
In [Eurocrypt 2004] Katz and Ostrovsky establish the exact round complexity of secure two-party computation with respect to black-box proofs of security. They prove that 5 rounds are necessary for secure two-party protocols (4-round are sufficient if only one party receives the output) and provide a protocol that matches such lower bound. The main challenge(More)
A garbling scheme is used to garble a circuit C and an input x in a way that reveals the output C(x) but hides everything else. In many settings, the circuit can be garbled off-line without strict efficiency constraints, but the input must be garbled very efficiently on-line, with much lower complexity than evaluating the circuit. Yao's scheme has(More)