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This paper investigates the design of S-boxes used for combining linear feedback shift register (LFSR) sequences in combination generators. Such combination generators have higher throughput than those using Boolean functions as the combining functions. However, S-boxes tend to leak more information about the LFSR sequences than Boolean functions. To study(More)
—Recent research results on tree-based Oblivious RAM by Shi et al. [15] obtain communication complexity of O(l · log 3 (N)) in the worst-case for an N-capacity storage with blocks size l. The individual nodes in the tree, however, are constructed using traditional ORAMs which have worst-case communication complexity linear in their capacity and block size.(More)
When a shadow of a threshold scheme is publicized, new shadows have to be reconstructed and redistributed in order to maintain the same level of security. In this paper we consider threshold schemes with disenrollment capabilities where the new shadows can be created by broadcasts through a public channel. We establish a lower bound on the size of each(More)
— In this paper, we address the problem of countering the control channel jamming in wireless communication systems. Targeting control traffic on a system like GSM (e.g., BCCH channel) leads to smart attacks that are four orders of magnitude more efficient than blind jamming. We propose several schemes based on coding theory and its applications that can(More)
In this paper, we consider the problem of mutually authenticated key exchanges between a low-power client and a powerful server. We show how the Jakobsson-Pointcheval scheme proposed recently [15] can be compromised using a variant of interleaving attacks. We also propose a new scheme for achieving mutually authenticated key exchanges. The protocol is(More)
Pseudorandom binary sequences with high linear complexity and low correlation function values are sought in many applications of modern communication systems. A new family of pseudorandom binary sequences, cascaded GMW sequences, is constructed. These sequences are shown to share many desirable correlation properties with the GMW sequences of Gordon, Mills,(More)
In this paper we study the cross-correlation function values of geometric sequences obtained from q-ary m-sequences whose underlying m-sequences are linearly or quadrat-ically related. These values are determined by counting the points of intersection of pairs of hypeplanes or of hyperplanes and quadric hypersurfaces of a finite geometry. The results are(More)
Private Information Retrieval (PIR) allows a user to retrieve bits from a database while hiding the user's access pattern. However, the practicality of PIR in a real-world cloud computing setting has recently been questioned. In such a setting, PIR's enormous computation and communication overhead is expected to outweigh the cost saving advantages of cloud(More)