We introduce a lattice-based group signature scheme that provides several noticeable improvements over the contemporary ones: simpler construction, weaker hardness assumptions, and shorter sizes of keys and signatures. Moreover, our scheme can be transformed into the ring setting, resulting in a scheme based on ideal lattices, in which the public key and signature both have bitsize Õ(n·logN), f...

For various well-known proofs of knowledge, we address the problem of how much information a cheating polynomial-time veriier can learn about individual bits of the prover's secret key. Speciically, under the widely believed assumption that the Schnorr identiication protocol is witness hiding, no polynomial-time veriier can distinguish the O(log k) most signiicant bits of the prover's secret ke...

The problem of proving a number is of a given arithmetic format with some prime elements, is raised in RSA undeniable signature, group signature and many other cryptographic protocols. So far, there have been several studies in literature on this topic. However, except the scheme of Camenisch and Michels, other works are only limited to some special forms of arithmetic format with prime element...

We study the computational complexity of finding stable outcomes in hedonic games, which are a class of coalition formation games. We restrict our attention to symmetric additively-separable hedonic games, which are a nontrivial subclass of such games that are guaranteed to possess stable outcomes. These games are specified by an undirected edgeweighted graph: nodes are players, an outcome of t...