Abstract Attribute-Based Encryption (ABE) is a relatively new encryption technology which is similar to multi-receiver encryption but the privacy of ciphertext receivers is protected by a set of attributes such that no one, even the encryptor, knows the identities of the receivers. Although the identities of those receivers remain unknown, the encryptor can ensure that all of the receivers cannot decrypt the ciphertext except for those who match the restrictions on predefined attribute values associated with the ciphertext. However, maintaining the correctness of users¡¦ attributes will take huge cost because the interactions between all users and the key generation center (KGC) are required to renew all of their private keys whenever a user joins, leaves the group, or updates the value of any of his attributes. Since user joining, leaving, and attribute updating may occur frequently in real situations, membership management will become a quite important issue in an ABE system but no existing scheme can perfectly cope with this problem. In this manuscript, we will present an ABE scheme which aims at the issue on dynamic membership management. Our work keeps high flexibility of the constrains on attributes and makes it possible for the procedures of user joining, leaving, and attribute updating to be dynamic, that is, it is not necessary for those users who do not update their attribute statuses to renew their private keys when some user changes his status. Finally, we also formally prove the security of the proposed scheme.

Thesis (D. Miss.)--Western Seminary, Portland, OR, 2002. / Abstract. Includes bibliographical references (leaves 277-284).

Thesis (D. Min.)--Trinity International University, 2000. / Abstract. Includes bibliographical references (leaves 110-114).

Thesis (J.C.L.)--Catholic University of America, 2000. / Includes bibliographical references (leaves 53-55).

Thesis (Th. M.)--St. Vladimir's Orthodox Theological Seminary, 2008. / Abstract. Description based on microfiche version record. Includes bibliographical references (leaves 202-209).

Thesis (D. Min.)--Northern Baptist Theological Seminary, Lombard, Ill., 2002. / Abstract. Includes bibliographical references (leaves 149-154).

Thesis (D. Min.)--Covenant Theological Seminary, 2003. / Abstract. Includes bibliographical references (leaves 241-247).

The concept of social membership is the mainframe for this dissertation, which encompasses four independent articles that approach the boundaries of social membership from different perspectives. Empirically, the focus lies on mobilizing groups that demand an extension of rights and/or inclusion for documented and undocumented immigrants in two European immigration countries: Sweden and Spain. I have defined the processes through which mobilizing actors (immigrants themselves and diverse supporters of their cause) interact with boundary-making actors (institutional actors, policy makers), whom through their positions participate in drawing the boundaries between inclusion and exclusion, as negotiating social membership. To study these processes, I have performed 68 interviews with actors as mobilizing immigrants, activists mobilizing on behalf of immigrants, representatives of NGOs and trade unions, policy-makers and politicians. Two main types of claims appeared: undocumented migrants’ rights groups mobilizing for residence permits and social rights, and documented immigrants’ (and their supporters’) advocacy against ethnic discrimination. Furthermore, I have included a study that reflects the tensions over social membership within immigrant communities. The gendered dimension is its main focus, as it illustrates the value conflicts over gender equality and ethnic diversity brought to the surface through the debates following so-called honour killings in Sweden, and the difficulties faced by young immigrant women mobilizing simultaneously against racism and patriarchal oppression.  The thesis consists of four independent articles within the overall framework of mobilizing groups demanding extended rights for and/or inclusion of immigrants. By using immigrants’ rights mobilizations, negotiations, debates and agendas, my general aim has been to explore the processes through which social membership is being contested and negotiated by a wide range of actors. In doing so, it has been possible to reveal how legal and symbolic boundaries create exclusionary processes that pose constraints on the social membership of immigrants with different legal statuses. / <p>At the time of the doctoral defense, the following paper was unpublished and had a status as follows: Paper 1: Manuscript.</p>

This study seeks to investigate this core research topic: how identity is involved in everyday interactions between Chinese microblogging website users? By understanding identity as an element in the interaction context of discursive practices, the investigation is achieved through the analysis of naturally occurring text-based online data. Conversation Analysis (CA) and Membership Categorization Analysis (MCA) are used to do the analysis. The former will focus on the interaction structure while the latter will be used to make some of the contents in the interactions relevant. This study seeks to make the “orderliness” (Sacks, 1972) and “members’ methods” (Garfinkel, 1967) under a particular context describable and analyzable. The sequential and categorical organization described in this study shows how members are oriented to identities in the in situ context when they exchange their ideas on a sensitive topic, and on a microblogging website. / text

The purpose of the simulation was to assess the impact of weight pattern assignment when using the multiple membership random effects model (MMREM). In contrast with most previous methodological research using the MMREM, mobility was not randomly assigned; rather the likelihood of student mobility was generated as a function of the student predictor. Two true weights patterns were used to generate the data (random equal and random unequal). For each set of generated data, the true correct weights and two incorrect fixed weight patterns (fixed equal and fixed unequal) that are similar to those used in practice by applied researchers were used to estimate the model. Several design factors were manipulated including the percent mobility, the ICC, and the true generating values of the level one and level two mobility predictors. To assess parameter recovery, relative parameter bias was calculated for the fixed effects and random effects variance components. Standard error (SE) bias was also calculated for the standard errors estimated for each fixed effect. Substantial relative parameter bias differences between weight patterns used were observed for the level two school mobility predictor across conditions as well as the level two random effects variance component, in some conditions. Substantial SE bias differences between weight patterns used were also found for the school mobility predictor in some conditions. Substantial SE and parameter bias was found for some parameters for which it was not anticipated. The results, discussion, future directions for research, and implications for applied researchers are discussed.