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The simulation paradigm, introduced by Goldwasser, Micali and Rackoff, is of fundamental importance to modern cryptography. In a breakthrough work from 2001, Barak (FOCS\'01) introduced a novel non-black-box simulation technique. This technique enabled the construction of new cryptographic primitives, such as resettably-sound zero-knowledge arguments, that cannot be proven secure using just black-box simulation techniques.
The work of Barak and its follow-ups, however, all require stronger cryptographic hardness assumptions than the minimal assumption of one-way functions: the work of Barak requires the existence of collision-resistant hash functions, and a very recent result by Bitansky and Paneth (FOCS\'12) instead requires the existence of an Oblivious Transfer protocol.
In this work, we show how to perform non-black-box simulation assuming just the existence of one-way functions. In particular, we demonstrate the existence of a constant-round resettably-sound zero-knowledge argument based only on the existence of one-way functions. Using this technique, we determine necessary and sufficient assumptions for several other notions of resettable security of zero-knowledge proofs. An additional benefit of our approach is that it seemingly makes practical implementations of non-black-box zero-knowledge viable.
We propose a method for de-identification of images that effectively prevents face recognition software (using the most popular and effective algorithms) from identifying people, but still allows human recognition. We evaluate our method experimentally by adapting the CSU framework and using the FERET database. We show that we are able to achieve strong de-identification while maintaining reasonable image quality.
In this short note, we demonstrate that the existence of one-way functions implies the existence of an $\\omega(1)$-round simultaneously resettable witness indistinguishable argument.
schemes that would be vulnerable to linear algebra attacks were they
based on ``usual\" algebras as platforms.
We propose the first general-purpose construction that avoids all these drawbacks: it is efficient, it requires no user interaction whatsoever (except for data up- and download), and it allows evaluating any dynamically chosen function on inputs encrypted under different independent public keys. Our solution assumes the existence of two non-colluding but untrusted servers that jointly perform the computation by means of a cryptographic protocol. This protocol is provably secure in the semi-honest model. We demonstrate the applicability of our result in two real-world scenarios from different domains: Privacy-Preserving Face Recognition and Private Smart Metering. Finally, we give a performance analysis of our general-purpose construction to highlight its practicability.
Our main contribution is to show that if the secret key polynomials of the encryption scheme are selected from discrete Gaussians, then the public key, which is their ratio, is statistically indistinguishable from uniform over its range. We also show how to rigorously extend the encryption secret key into a signature secret key. The security then follows from the already proven hardness of the R-SIS and R-LWE problems.
Each 258-bit integer is represented as a polynomial with five,65 bit signed integer, coefficients . Exploiting this splitting we designed a pipelined 65-bit multiplier based on new Karatsuba-Ofman variant using non-standard splitting to fit to the Xilinx embedded digital signal processor (DSP) blocks.
Our architecture is able to compute 258-bit multiplication suitable for BN curves using only 11 in-built DSP blocks available on Virtex-6
Xilinx FPGA devices. It is the least DSP blocks consumption in the known literature. This work can be extended to efficiently compute pairings at higher security levels.