en Material Managment Material Managment پژوهشي Research <p><font size="2"><font face="times new roman,times,serif"> <strong><i>Abstract : </i></strong><i>A </i><i>visual cryptography scheme based on </i><i>a given </i><i>graph G is a </i><i>method to distribute a secret image among the vertices of G, the participants, so that</i> <i>a subset of participants can recover the secret image if they contain an edge of G, by stacking their shares, otherwise they can obtain no information regarding the secret</i> <i>image. In this paper </i><i>a </i><i>maximal independent sets of the graph G </i><i>was applied </i><i>to propose a lower bound on the pixel expansion of visual cryptography schemes with graph access </i><i>structure </i><i> </i><i>(G </i><i>). </i><i><i>In addition </i><i>a lower bound on the pixel expansion of </i><i>basis matrices C₅ and Peterson graph access structure</i> <i><i>were presented . </i><i></i></i></i></font></font></p><p>  </p> Keywords : Sharing Schemes, Visual Cryptography, Graph Access Structure 13 16 http://ijiepr.iust.ac.ir/browse.php?a_code=A-10-1-16&slc_lang=en&sid=1 M. Hadian Dehkordi 18003194753284600328 18003194753284600328 Yes A. Cheraghi a_cheraghi@iust.ac.ir 18003194753284600329 18003194753284600329 No