06080107

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06080107 Simon, Hans Ulrich Boolean composition of visual secret sharing schemes. Hirsch, Edward A. (ed.) et al., Computer science -- theory and applications. 7th international computer science symposium in Russia, CSR 2012, Nizhny Novgorod, Russia, July 3--7, 2012. Proceedings. Berlin: Springer (ISBN 978-3-642-30641-9/pbk). Lecture Notes in Computer Science 7353, 314-325 (2012). 2012 Berlin: Springer EN

doi:10.1007/978-3-642-30642-6_29

Summary: In this paper, we analyze the disjunction and the conjunction of two access structures for visual secret sharing schemes. The latter operation, when applied to $k$-out-of-$n$ schemes, leads to schemes with multiple thresholds. We precisely determine the maximum relative contrast for schemes of this type. As in the case of classical schemes with a single threshold, the analysis proceeds by revealing a central relation between the relative contrast in a visual secret sharing scheme and the error-term in a related problem of approximation-theoretic flavor.