The optimal pixel expansion of an ( <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">n</i> , ) visual cryptographic scheme (VCS) was proven as 2 <sup xmlns:xlink="http://www.w3.org/1999/xlink">n-1</sup> in 1995; and that a (2, )-VCS proposed 2002. Yet, most existing best expansions xmlns:xlink="http://www.w3.org/1999/xlink">k</i> )-VCSs for ≥ 3 have not been improved since 1996. Whether they are already optimal, if how to find the optimums never...

A conventional threshold ( <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">k</i> out of xmlns:xlink="http://www.w3.org/1999/xlink">n</i> ) visual secret sharing scheme encodes one image xmlns:xlink="http://www.w3.org/1999/xlink">P</i> into transparencies (called shares) such that any group reveals when they are superimposed, while less than ones cannot. We define and develop general constructions for multiple-secret cryptographic schemes (MVCSs)...

Given a secret image S, set P of n participants and strong access structure (Γ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Qual</sub> , Γ xmlns:xlink="http://www.w3.org/1999/xlink">Forb</sub> ), visual cryptographic scheme (VCS) for general structures (GVCS) encodes S into shares transparencies such that the each qualified in ΓQual can reveal by superimposing their shares; whereas those any forbidden ΓForb obtain nothing about S. Elegant...

A threshold k out of n, or (k, n), secret sharing with perfect security encodes a into n shadows for the participants such that any are capable reconstructing using their shadows, while less than ones cannot obtain information about secret. The shared data is not only safeguarded by in access structure, but also tolerant to loss up n̶k shadows. Exploiting properties orthogonal Latin k-cubes, we propose novel scheme security. correctness and our formally proved. It first based on cubes....

We extend the sharing scheme proposed by Mignotte in 1983 based upon Chinese remainder theorem (CRT) to devise a threshold secret for digital images. Given image I and set of n participants I, our encrypts into shadows such way that any group r can recover while less than cannot where 2 ≤ n. As compared similar work Meher Patra 2006, which is not scheme, design satisfies requirements so it more technically sound. Our reveals new research area applying CRT sharing.

This paper re-examines the problem of visual secret sharing for general access structures by using cryptograms random grids (VCRG). Given a binary or color image shared set <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">n</i> participants with strong structure, we devise two effective algorithms to produce VCRG so that members in each qualified can reconstruct superimposing their shares, while those any forbidden cannot. Our do not require extra...

A region incrementing visual cryptography scheme (RIVCS) deals with the sharing of an image consisting multiple regions different secrecy levels, which can be incrementally revealed as number shares increases. The encoding basis matrices RIVCS for containing three to five have been reported in literature, but no construction method has ever studied. We develop a novel and efficient using linear programming this paper. proposed integer program aims at minimization pixel expansion under...

A k out of n visual cryptographic scheme [(k, n)-VCS] encodes a secret image P into transparencies (shares) in such way that any shares reveal sense when they are superimposed (equivalent to the "OR" operation), while k-1 or less cannot. (k, n)-XVCS achieves same goal with better contrast on reconstructed result "XOR"ed shares. It has been proved n)-VCS is also n)-XVCS. However, monotonously increasing property (that k+1,k+2,...,n P) most conventional n)-VCSs not guaranteed applied as...

Abstract The ant colony optimization is a meta-heuristic inspired by knowledge sharing amongst ants using pheromone, which serves as kind of collective memory. Since the past few years, there have been several successful applications this new approach for finding approximate solutions computationally difficult problems in reasonable times. In paper, we study generalized minimum spanning tree problem that involves design weight connected network at least one node out every disjoint subset...

Computer supported collaborative learning (CSCL) which helps to increase the social interactions among learners without constraint of time and space as it would be in real classrooms has prevailed e-learning technologies. However,the studies group formation that involve with diverse characteristics such style students or concern have rarely been conducted. Due fact allocating into groups is an NP-hard problem, we propose a particle swarm optimization (PSO) algorithm cope problem constructing...

In a conventional threshold k out of n visual cryptographic scheme (( k,n)-VCS, for short), one secret image P can be encoded into seemingly random transparencies (called shares) such that the superimposed result any group or more reveal to our eyes, while less than ones cannot. To ease management and identification, shares may look meaningful, instead random, pictures. Given shared by participants cover C, we study ( k, n)-VCS with meaningful (denoted as n)-VCS-MS) in this letter where...

We design innovative algorithms for visual multiple-secret sharing using circle or cylinder random grids in this paper. Formal validations, security analyses, and computer implementations are discussed to demonstrate the correctness feasibility of our algorithms. As compared schemes developed conventional cryptography, delivers three significant advantages: (1) it is capable multiple (instead only one two) secret images two shares; (2) does not result any extra pixel expansion so that sizes...