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Assume that each object in a database has <i>m</i> grades, or scores, one for each of <i>m</i> attributes. For example, an object can have a color grade, that tells how red it is, and a shape grade, that tells how round it is. For each attribute, there is a sorted list, which lists each object and its grade under that attribute, sorted by grade (highest(More)
In this paper we consider a new type of cryptographic scheme, which can decode concealed images without any cryptographic computations. The scheme is perfectly secure and very easy to implement. We extend it into a visual variant of the k out of n secret sharing problem, in which a dealer provides a transparency to each one of the n users; any k of them can(More)
We deal with the problem of a center sending a message to a group of users such that some subset of the users is considered revoked and should not be able to obtain the content of the message. We concentrate on the stateless receiver case, where the users do not (necessarily) update their state from session to session. We present a framework called the(More)
We propose a family of constant-degree routing networks of logarithmic diameter, with the additional property that the addition or removal of a node to the network requires no global coordination, only a constant number of linkage changes in expectation, and a logarithmic number with high probability. Our randomized construction improves upon existing(More)
In this work we provide efficient distributed protocols for generating shares of random noise, secure against malicious participants. The purpose of the noise generation is to create a distributed implementation of the privacy-preserving statistical databases described in recent papers [14, 4, 13]. In these databases, privacy is obtained by perturbing the(More)
We show how to construct a public-key cryptosystem (as originally defined by DiNe and Hellman) secure against chosen ciphertezt attacks, given a public-key cryptosystern secure against passive eavesdropping and a noninteractive zero-knowledge proof system in the shared string model. No such secure cryptosystems were known before. A concrete implementat ion(More)
We describe efficient constructions for two oblivious twoparty computation problems: l-out-of-N Oblivious Transfer &d ‘Oblivious Poly&nial Evaluation. The oblivious polynomial evaluation protocol is based on a new intractability assumption which is closely related to noisy polynomial re construction. A direct corollary of the l-out-of-N OT protccol is an(More)
<b>1 Introduction</b><br> Oblivious Transfer (OT) protocols allow one party, the sender,to transmit part of its inputs to another party, the chooser, in amanner that protects both of them: the sender is assured that thechooser does not receive more information than it is entitled,while the chooser is assured that the sender does not learn whichpart of the(More)