Implementation of Steganographic Algorithms Based on Exact Histogram Matching and Colour Visual Cryptography

Sensitive secret data transmission through internet has been of great security concern which can be overcome by steganographic methods achieved through secret image sharing. Two novel steganographic secret algorithms based on colour visual cryptography and exact histogram specification is proposed in the present study. The former approach combines colour visual cryptography with a secret key to produce less distorted meaningful share images. A specified histogram acts as the key for the second approach and provides better security and data obscurity compared to conventional approaches. A novel histogram specification method is also proposed which exactly matches the histogram of an image to a specified histogram

Characteristics of Markets and Patients Served by ESRD Seamless Care Organizations

Under the Comprehensive End-stage Renal Disease (ESRD) Care (CEC) Model, dialysis facilities and nephrologists form ESRD Seamless Care Organizations (ESCOs) to deliver high value care. This study compared the characteristics of patients and markets served and unserved by CEC and assessed its generalizability. ESCOs operated in 65 of 384 markets. ESCO markets were larger than non-ESCO markets, had fewer White patients, higher household income, and higher Medicare spending per patient. Patients in ESCOs were similar to eligible nonaligned patients in age and sex but differed in race/ethnicity and were more often treated in an urban area; comorbidity prevalence differed modestly. CEC is available to a meaningful share of the dialysis population and relatively few dialysis patients resided in a market where no provider could meet the participation threshold, so market size may not be the primary barrier for potential new participants in CEC or future kidney care models.

HISTORICALLY ROOTED POLITICAL FACTORS OF POST-SOVIET SOCIAL SITUATION IN KABARDINO-BALKAR REPUBLIC: EXPERIENCE OF THE 1990-2000s

В условиях постсоветского политического перехода обнаружился резкий рост влияния историко-политических факторов регионального развития на Северном Кавказе. В Кабардино-Балкарии они проявили себя как во внутриреспубликанских, так и в «центр-периферийных» отношениях. Первый аспект проблемы связан преимущественно с последствиями депортации балкарского населения в 1944 г. и последующими проблемами его реабилитации. Второй аспект наиболее ярко проявился в дискуссиях о последствиях Кавказской войны и «черкесском вопросе». В статье осуществлен сопоставительный анализ этих двух историко-политических факторов, формы и степень влияния которых на общественную ситуацию современной Кабардино-Балкарии весьма различаются. «Полная реабилитация» балкарского народа подразумевала не только символический, но и непосредственный материальный результат – закрепление за балкарским населением значительной части территориальных и властных ресурсов республики. Мыслимые результаты решения черкесского вопроса носили более отдаленный и абстрактный характер и не предполагали непосредственных изменений в лучшую сторону для кабардинского населения КБР. Требование «полной реабилитации» балкарского народа находило опору в российских и республиканских политико-правовых актах и принимало форму выполнения уже принятых решений, тогда как черкесский вопрос имел форму притязаний адыгских национальных организаций, не располагавших полномочиями и ресурсами для его решения. Реабилитация подразумевала изменения только внутренней этнополитической структуры Кабардино-Балкарской Республики, тогда как разрешение «черкесского вопроса» требовало действий на национальном и международном уровне и т.д. Но как историко-политические феномены они характеризуются сущностным единством, будучи направлены на «преодоление последствий» определенных событий прошлого путем создания особых условий для отдельных этнических групп населения сегодня. In the conditions of the Post-soviet political transition sharp rise of the influence of historically rooted political factors of regional development in the North Caucasus became visible. In Kabardino-Balkaria they manifested themselves in intra-republican as well as in “center-periphery” relations. The first aspect of the problem was related to the consequences of deportation of the Balkar population in 1944 and the problems of their subsequent rehabilitation. The second one most saliently revealed itself in the discussions of the Caucasian war aftermath and of the so called “Circassian question”. The article presents comparative analysis of these two historically rooted political factors that essentially differed in the forms and intensity of their influence on the social situation in modern Kabardino-Balkaria. “Complete rehabilitation” of the Balkar people implied not only symbolic but also immediate material result – securing for the Balkar population the meaningful share of territorial and power resources of the republic. Eventual outcomes of the Circassian question’s solution were more far away and abstract and did not imply immediate improvement of the KBR Kabardin population’s condition. Demand of “complete rehabilitation” of the Balkar people was based on Russia’s and Kabardino-Balkar republic’s political and legal acts and took the form of realizing of the decisions already made, while “Circassian question” represented a set o claims by the Adyghe national organizations devoid of powers and resources to implement them. Rehabilitation was meant to change only inner ethno-political structure of the Kabardino-Balkar Republic while “Circassian question” involved actions on the national and international level etc. Nevertheless they have essentially common traits being oriented at the “overcoming the consequences” of the past events by creating the special conditions for separate ethnic groups today.

Image Secret Sharing Construction for General Access Structure with Meaningful Share

This article describes how the (k, n) threshold image secret sharing technology can recover the secret image even n − k shares are lost, or n−k servers do not work, which is useful for cloud storage, etc. Image secret sharing for general access structure (GAS) is more general than (k, n) threshold. Image secret sharing with a meaningful share will decrease encryption suspicion so that the security can be enhanced. However, traditional studies have no image secret sharing construction approach for GAS with a meaningful share. In the article, they first exploit an image secret sharing construction approach for GAS with meaningful share. Following their construction approach, the authors develop a random grid (RG)-based visual secret sharing (VSS) algorithm for GAS with meaningful share as well as polynomial-based image secret sharing for GAS with meaningful share. The experiments with this concept exhibit the effectiveness of the algorithms and further their construction approach.

Expansion-Free Grayscale Image Sharing Using Meaningful Share Images

Since Naor and Shamir introduced visual cryptography in 1994, numerous image sharing techniques have been proposed to protect the security of binary, gray, and color images. However, only few of them focus on grayscale image sharing. Because the size of the share images are usually very large, an image sharing method that can create share images with the same size as that of the secret image (expansion free) is more attractive. This study aims to propose a grayscale image sharing method to achieve the purposes of free expansion and meaningful image sharing simultaneously. Experimental results show that two meaningful share images can be effectively created by the proposed share image creation process. Moreover, the original grayscale secret image can be correctly decoded by the proposed secret image retrieval process.

Meaningful Share Generation for Increased Number of Secrets in Visual Secret-Sharing Scheme

This paper presents a new scheme for hiding two halftone secret images into two meaningful shares created from halftone cover images. Meaningful shares are more desirable than noise-like (meaningless) shares in Visual Secret Sharing because they look natural and do not attract eavesdroppers' attention. Previous works in the field focus on either increasing number of secrets or creating meaningful shares for one secret image. The method outlined in this paper both increases the number of secrets and creates meaningful shares at the same time. While the contrast ratio of shares is equal to that of Extended Visual Cryptography, two secrets are encoded into two shares as opposed to one secret in the Extended Visual Cryptography. Any two natural-looking images can be used as cover unlike the Halftone Visual Cryptography method where one cover should be the negative of the other cover image and can only encode one secret. Effectiveness of the proposed method is verified by an experiment.