In dynamic threshold schemes the dealer is able (after a preprocessing stage) to allow sets of participants of a given cardinality to reconstruct diierent secrets (in diierent time instants) by sending them the same broadcast message. In this paper we provide a tight lower bound on the number of random bits needed by the dealer to set up a dynamic threshold scheme.

The secret sharing schemes are the important tools in cryptography that are used as building blocks in many secured protocols. It is a method used for distributing a secret among the participants in a manner that only the threshold number of participants together can recover the secret and the remaining set of participants cannot get any information about the secret. Secret sharing schemes are ...

An extended visual secret sharing (EVSS) scheme with innocent looking (unsuspicious) cover images was firstly proposed by Naor and Shamir. Most recent papers about EVSS schemes are dedicated to get a higher contrast of the concealed secret or a less size of shadow image. The conventional EVSS scheme uses the whiteness of black and white sub pixels to represent the gray level of the covered imag...

Each member of an n-person team has a secret, say a password. The k out of n gruppen secret sharing requires that any group of k members should be able to recover the secrets of the other n−k members, while any group of k−1 or less members should have no information on the secret of other team member even if other secrets leak out. We prove that when all secrets are chosen independently and hav...

In [3] Damgard and Thorbek proposed the linear integer secret sharing (LISS) scheme. In this note we show that the LISS scheme can be made proactive.

In this research, we explore the impact on teachers of implementation of the Faculty Student KnowledgeSharing Platform (FSKSP) in their college. Specifically, we focus on the effect on those teachers of the need to share publicly their knowledge and teaching material as the result of FSKSP implementation. In addition, we report the experience and progress they acquire when choosing to change th...

In this paper, we consider methods whereby a subset of players in a (k, n)-threshold scheme can “repair” another player’s share in the event that their share has been lost or corrupted. This will take place without the participation of the dealer who set up the scheme. The repairing protocol should not compromise the (unconditional) security of the threshold scheme, and it should be efficient, ...

In recent years there has been a great deal of work done on secret sharing schemes. Secret Sharing Schemes allow for the division of keys so that an authorised set of users may access information. In this paper we wish to present a critical comparison of two of these Schemes based on Latin Squares [3] and RSA [9]. These two protocols will be examined in terms of their positive and negative aspe...