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Standard 0 = 1 cold dark matter (CDM) needs 0:27 < 8 < 0:63 (2 ) to t the observed number of large separation lenses, and the constraint is nearly independent of H0 = 100h 1 km s 1 Mpc . This range is strongly inconsistent with the COBE estimate of 8 = (2:8 0:2)h. Tilting the primordial spectrum / k n from n = 1 to 0:3 < n < 0:7, using an e ective Hubble constant of 0:15 < = h < 0:30, or reduci...

In this paper, we prove classical coin-flipping secure in the presence of quantum adversaries. The proof uses a recent result of Watrous [20] that allows quantum rewinding for protocols of a certain form. We then discuss two applications. First, the combination of coin-flipping with any non-interactive zero-knowledge protocol leads to an easy transformation from non-interactive zero-knowledge t...

The Eternal system provides a novel methodology for the consistent replication of objects in an adaptive, faulttolerant, CORBA-compliant distributed system that is susceptible to partitioning. Passive and active replication schemes are supported in Eternal, and mechanisms are provided for the interaction of objects with different replication schemes. Nested operations for both passive and activ...

We introduce implicit zero-knowledge arguments (iZK) and simulation-sound variants thereof (SSiZK); these are lightweight alternatives to zero-knowledge arguments for enforcing semi-honest behavior. Our main technical contribution is a construction of efficient two-flow iZK and SSiZK protocols for a large class of languages under the (plain) DDH assumption in cyclic groups in the common referen...

Groth-Sahai proofs are efficient non-interactive zero-knowledge proofs that have found widespread use in pairing-based cryptography. We propose efficiency improvements of Groth-Sahai proofs in the SXDH setting, which is the one that yields the most efficient non-interactive zero-knowledge proofs. – We replace some of the commitments with ElGamal encryptions, which reduces the prover’s computati...

The logarithmic Sobolev inequality is a spectral bound which provides much information about decay to equilibrium of the dynamics of a stochastic process. Consider a process governed by reversible dynamics described by a generator L, with semi-group Pt and an invariant measure μ. The Dirichlet form is defined as Dμ(f) = μ[f(−L)f ]. A logarithmic Sobolev inequality is a statement which says that...

We revisit the definitions of zero-knowledge in the Common Reference String (CRS) model and the Random Oracle (RO) model. We argue that even though these definitions syntactically mimic the standard zero-knowledge definition, they loose some of its spirit. In particular, we show that there exist a specific natural security property that is not captured by these definitions. This is the property...

Recent efficient constructions of zero-knowledge Succinct Non-interactive Arguments of Knowledge (zk-SNARKs), require a setup phase in which a common-reference string (CRS) with a certain structure is generated. This CRS is sometimes referred to as the public parameters of the system, and is used for constructing and verifying proofs. A drawback of these constructions is that whomever runs the ...