Dependable security by twisted secret sharing

Abstract

Large scale networked infonnation systems are referred to as critical infonnation infrastructures when they provide critical services to the critical physical infrastructures. Critical infonnation infrastructures contain specific nodes that provide security services, like authentication servers; those are called security or trust centres. The goal of this research is to find an algorithm for enabling those centres to become sustainable by sharing their (superfluous) security resources and to resist Byzantine failures. The proposed secret sharing algorithm takes care of allocating in advance the secret content of the suffering centre to other healthy centres, so that only an arbitrary majority of them can reconstruct the content. This perfect t,n- threshold scheme is suitable in dynamic networks as it has an adaptive access structure. It is compared to existing schemes rather simple as it is purely based on permutations. It is efficient, i.e, favourable information rate, as all shares are much shorter than the secret itself. Secondarily, each secret share is even additionally protected (encrypted) against the holder as weil against any outsider. © 2004 by Springer Science+Business Media Dordrecht.