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We consider the problem of extending oblivious transfers: Given a small number of oblivious transfers “for free,” can one implement a large number of oblivious transfers? Beaver has shown how to extend oblivious transfers given a one-way function. However, this protocol is inefficient in practice, in part due to its non-black-box use of the underlying(More)
We refine the complexity analysis of approximation problems by relating it to a new parameter calledgap location. Many of the results obtained so far for approximations yield satisfactory analysis with respect to this refined parameter, but some known results (e.g.,max-k-colorability, max 3-dimensional matching andmax not-all-equal 3sat) fall short of doing(More)
The Cipher Block Chaining (CBC) Message Authentication Code (MAC) is an authentication method which is widely used in practice. It is well known that the use of the CBC MAC for variable length messages is not secure, and a few rules of thumb for the correct use of the CBC MAC are known by folklore. The first rigorous proof of the security of CBC MAC, when(More)
The growing gap between the speed of memory access and cache access has made cache misses an influential factor in program efficiency. Much effort has been spent recently on reducing the number of cache misses during program run. This effort includes wise rearranging of program code, cache-conscious data placement, and algorithmic modifications that improve(More)
Reference-counting is traditionally considered unsuitable for multiprocessor systems. According to conventional wisdom, the update of reference slots and reference-counts requires atomic or synchronized operations. In this work we demonstrate this is not the case by presenting a novel reference-counting algorithm suitable for a multiprocessor system that(More)
We introduce the notion of escrowed identity, an application of key-escrow ideas to the problem of identi cation. In escrowed identity, one party A does not give his identity to another party B, but rather gives him information that would allow an authorized third party E to determine A's identity. However, B receives a guarantee that E can indeed determine(More)
Uniform Generation of NP-witnesses using an NP-oracle Mihir Bellare Oded Goldreichy Erez Petrankz May 1998 Abstract A Uniform Generation procedure for NP is an algorithm which given any input in a xed NP-language, outputs a uniformly distributed NP-witness for membership of the input in the language. We present a Uniform Generation procedure for NP that(More)
With concurrent and garbage collected languages like Java and C# becoming popular, the need for a suitable non-intrusive, efficient, and concurrent multiprocessor garbage collector has become acute. We propose a novel mark and sweep on-the-fly algorithm based on the sliding views mechanism of Levanoni and Petrank. We have implemented our collector on the(More)