With rapid developments in network technology, information security is becoming increasingly crucial. To ensure that secret images are not being stolen during transmission, a good countermeasure is to encrypt them before transmission. Visual secret sharing (VSS) is a type of secure communication technology in which a secret image is encrypted into some shares and then restored through human vision by superimposing shares. A random grid is a pivotal VSS technique. Because computation and pixel expansion is not needed in the decrypting phase, many scholars have researched random grids for VSS. To minimize time consumption, some researchers have proposed high-capacity visual multiple secret sharing (VMSS) schemes that can encrypt multiple images simultaneously, although some difficulty is encountered in share management. A meaningful VSS scheme provides a solution for both distinguishing and management problems; however, it cannot handle restrictions on the number of secret images. For avoiding the abovementioned problems, this study proposes an advanced meaningful VMSS scheme that can flexibly adjust the quality between shares and restored images. Our scheme offers seven attractive features that make it notably flexible in theoretical and practical use.

Flexible meaningful visual multi-secret sharing scheme by random grids

The core objective of secret sharing concentrates on developing a novel technique that prevents the destruction and leakage of original data during the distribution and encoding processes. Progressive Visual Cryptography (VC) is considered for the potential over the traditional VC schemes since the former does not require and does not suffer from the limitations of requiring a minimum number of participants during the process of encryption and sharing. The chaotic map-based Progressive VC is superior in facilitating predominant secrecy under sharing and encryption. In this paper, an Improved Henon Chaotic Map-based Progressive Block-based VC (IHCMPBVC) scheme is proposed to prevent the leakage and destruction of sensitive information during an exchange and encryption. This proposed IHCMPBVC technique uses the merits of Henon and Lorentz maps for effective encryption since it introduces the option of deriving non-linear behavior that results in sequence generation that covers the complete range with proper distribution in order to minimize the degree of leaks in sharing. The simulation results of the proposed IHCMPBVC technique investigated using entropy, PSNR, and Mean Square Error were improved at an average rate of 27%, 23%, and 31%, predominant to the baseline VC approaches considered in the comparison. 

Improved Henon Chaotic Map-based Progressive Block-based visual cryptography strategy for securing sensitive data in a cloud EHR system

Region Incrementing Visual Cryptography (RIVC) is an important and active research area. In (2, n) region incrementing visual cryptographic scheme, a single secret image is divided into multiple secret regions. We need at least 2 secret shares to be superimposed to reveal the 1st secret region. By stacking more and more shares we get the entire image revealed. All the existing schemes for RIVCS suffer from the problems like color reversal, pixel expansion and low contrast. Also conventional RIVCS schemes generate noise like shares. The management of these shares is also problem, as there is no way to identify these shares. Thus we are proposing a new Extended RIVC scheme which uses the characteristics of both RIVCS and Extended VCS which adds a meaningful cover image to the shares. Our proposed method solves all the above mentioned drawbacks of the existing schemes. The main contributions in this paper are: a) No pixel expansion b)Meaningful share images c)Increased contrast d) No color reversal e) Improved Security.

T. Anila

Papers

An Extended Region Incrementing Visual Cryptography Scheme Using Unexpanded Meaningful Shares