Flaws in Strong t-Consistency

Abstract

Secret sharing is a cryptographic primitive used to securely distribute a secret value S among n participants such that only predetermined subsets of these participants (called access sets) can later reconstruct S. Such a scheme is said to be secure in the information theoretic setting if an adversary with unlimited computational power cannot reduce uncertainty regarding S.Harn and Lin proposed a strong (n, t, n) secret sharing scheme which they claim is information theoretic secure. In this paper we show that this is not the case and that the notion of strong t-consistency used by Harn and Lin as well as Liu et al. actually results in an imperfect scheme that is not secure in the information theoretic setting.