Multipurpose identity-based signcryption : a Swiss army knife for identity-based cryptography

Identity-Based (IB) cryptography is a rapidly emerging approach to public-key cryptography that does not require principals to pre-compute key pairs and obtain certificates for their public keys— instead, public keys can be arbitrary identifiers such as email addresses, while private keys are derived at any time by a trusted private key generator upon request by the designated principals. Despite the flurry of recent results on IB encryption and signature, some questions regarding the security and efficiency of practicing IB encryption (IBE) and signature (IBS) as a joint IB signature/encryption (IBSE) scheme with a common set of parameters and keys, remain unanswered. We first propose a stringent security model for IBSE schemes. We require the usual strong security properties of: (for confidentiality) indistinguishability against adaptive chosen-ciphertext attacks, and (for nonrepudiation) existential unforgeability against chosen-message insider attacks. In addition, to ensure as strong as possible ciphertext armoring, we also ask (for anonymity) that authorship not be transmitted in the clear, and (for unlinkability) that it remain unverifiable by anyone except (for authentication) by the legitimate recipient alone. We then present an efficient IBSE construction, based on bilinear pairings, that satisfies all these security requirements, and yet is as compact as pairing-based IBE and IBS in isolation. Our scheme is secure, compact, fast and practical, offers detachable signatures, and supports multirecipient encryption with signature sharing for maximum scalability.

Empowering the school community for change : an evaluation of participation in the Ashgrove Healthy School Environment Project

The purpose of this study was to evaluate aspects of participation in a participatory action research project, the Ashgrove Healthy School Environment Project. Participatory action research is a form of research that creates change as an explicit part of the research process and requires the active participation of those by and for whom the research is being conducted. This study arose from concems by this researcher, who is also a co-facilitator of the project, that levels of participation were not as extensive as one might have hoped and that this seemingly low level would have a negative impact on the continuing participation of those already involved. Specifically. this evaluation sought to uncover the reasons that prompted participation, to identify structural barriers to initial involvement and to uncover participants' perceptions of the process, including barriers and opportunities. It also sought to record evidence of any shift in decision making and to draw implications about the findings that could assist the project, the school, other schools and the wider community. This evaluation involved focus group discussions and interviews with participants actively involved in the school project. The purpose was to uncover their views, feelings and perceptions about their participation and the participatory processes in use generally. It also included some examination of school documents and newsletters and as also drawn on the reflections of this 'insider' researcher, based on two years of involvement in facilitating the project. The findings that emerge from this study are heartening. Rather than feeling anxious about the long-term sustainability of the project, this researcher now feels more confident about its achievements, both in terms of the changes that have occurred in the school and about the participatory processes and levels of participation. Whilst the evaluation has identified a number of barriers, both institutional, personal and project related, it has also identified several key factors that serve to promote participation.

Intercultural dance : exploring a Finnish migrant connection with indigenous cultures through dance

This research is a dance-based, autoethnographic study which explores my connection with place as a Savolainen woman born on Kalkadoon country; an Australian-born Finn. Edward Relph states 'the more profoundly inside a place the person feels, the stronger will be his or her identity with that place' (1976, 49). I am interested in how a sense of "place identity" has informed my choreographic practice. Autoethnography is important because it places the research within a lived experience: my insider account of a lived experience within the White Australia Policy through my lens as a first generation Australian-born Finn. It also speaks to the space in-between for those, like me, who feel they do not fit into mainstream identity but look like they do. By exploring my lived experience through dance autoethnography, new understandings of my place identity within a cultural, social and political context have emerged. Ellis and Flaherty state ‘subjectivity is situated such that the voices in our heads and the feelings in our bodies are linked to political, cultural, and historical contexts’ (1992, 4). In order to begin my rehearsal process, I wanted a cultural framework which related to connection with land to guide the research. My investigations led me to the Maori examples of "Tikanga Maori" (Tikanga are the customs and traditions), in particular the "Pepeha" (Introduction) and allowed me to challenge my choreographic practice through this cultural framework.

The impact of auditor independence regulations on established and emerging firms.

Purpose – The purpose of this paper is to study whether auditor independence reforms introduced in 2004 led to an enhancement in earnings quality in the post-reform era. Design/methodology/approach – This study predicts that as the cost of compliance will vary based on a firm's existing corporate governance regime and the level of external scrutiny (monitoring) it faces, we compare the earnings quality of a sample of “established” (S&P/ASX 100) to a sample of “emerging” (S&P/ASX Small Ordinaries Index) firms. The paper examines the reporting behaviour of the two groups of listed entities, covering the regulatory change period 2003-2006. The paper uses regression modelling to test the associations between increased audit independence, earnings quality and corporate governance mechanisms over the pre- and post-regulatory period. Findings – The paper's results confirm that earnings quality for the established firms was enhanced in the post-reform period; while this was not the case for emerging firms. The evidence also suggests that corporate governance mechanisms of board independence and board financial skill are associated with higher earnings quality; while the higher the concentration of insider firm ownership is associated with lower earnings quality. Practical implications – This study provides policy makers with evidence as to changes in reporting behaviour following law reform aimed at strengthening auditor independence. Originality/value – The studies on earnings quality are informed by the US market practices. Australia provides a unique setting through its auditor independence reforms to examine the impact of reform choices. This study also investigates two specific subsets of the market: established firms and emerging firms.

Review : "English language education across Greater China" by A. Feng

I have formally learned English from Year Four till the completion of my undergraduate study in China. Because of this personal history, I was keen to review this book and revisit English education in China. The list of contributors to the book includes Anwei Feng (editor) and his colleagues, who play an insider role in English language practice, research, and policy-making in ‘Greater China’. ‘Greater China’ according to Feng, can be defined as geographically close, demographically Chinese-dominated, and culturally, economically, and socio-politically interrelated countries and territories where Chinese is either the mother tongue or used as an official language.

Middle schooling and scientific literacy : bringing the students to science

This study is about young adolescents' engagement in learning science. The middle years of schooling are critical in the development of students' interest and engagement with learning. Successful school experiences enhance dispositions towards a career related to those experiences. Poor experiences lead to negative attitudes and rejection of certain career pathways. At a time when students are becoming more aware, more independent and focused on peer relationships and social status, the high school environment in some circumstances offers more a content-centred curriculum that is less personally relevant to their lives than the social melee surrounding them. Science education can further exacerbate the situation by presenting abstract concepts that have limited contextual relevance and a seemingly difficult vocabulary that further alienates adolescents from the curriculum. In an attempt to reverse a perceived growing disinterest by students to science (Goodrum, Druhan & Abbs, 2011), a study was initiated based on a student-centred unit designed to enhance and sustain adolescent engagement in science. The premise of the study was that adolescent students are more responsive toward learning if they are given an appropriate learning environment that helps connect their learning with life beyond the school. The purpose of this study was to examine the experiences of young adolescents with the aim of transforming school learning in science into meaningful experiences that connected with their lives. Two areas were specifically canvassed and subsumed within the study to strengthen the design base. One area that of the middle schooling ideology, offered specific pedagogical approaches and a philosophical framework that could provide opportunities for reform. The other area, the construct of scientific literacy (OECD, 2007) as defined by Holbrook and Rannikmae, (2009) appeared to provide a sense of purpose for students to aim toward and value for becoming active citizens. The study reported here is a self-reflection of a teacher/researcher exploring practice and challenging existing approaches to the teaching of science in the middle years of schooling. The case study approach (Yin, 2003) was adopted to guide the design of the study. Over a 6-month period, the researcher, an experienced secondary-science teacher, designed, implemented and documented a range of student-centred pedagogical practices with a Year-7 secondary science class. Data for this case study included video recordings, journals, interviews and surveys of students. Both quantitative and qualitative data sources were employed in a partially mixed methods research approach (Leech & Onwuegbuzie, 2009) dominated by qualitative data with the concurrent collection of quantitative data to corroborate interpretations as a means of analysing and developing a model of the dynamic learning environment. The findings from the case study identified five propositions that became the basis for a model of a student-centred learning environment that was able to sustain student participation and thus engagement in science. The study suggested that adolescent student engagement can be promoted and sustained by providing a classroom climate that encourages and strengthens social interaction. Engagement in science can be enhanced by presenting developmentally appropriate challenges that require rigorous exploration of contextually relevant learning environments; supporting students to develop connections with a curriculum that aligns with their own experiences. By setting an environment empathetic to adolescent needs and understandings, students were able to actively explore phenomena collaboratively through developmentally appropriate experiences. A significant outcome of this study was the transformative experiences of an insider, the teacher as researcher, whose reflections provide an authentic model for reforming pedagogy. The model and theory presented became an adjunct to my repertoire for science teaching in the middle years of schooling. The study was rewarding in that it helped address a void in my understanding of middle years of schooling by prompting me to re-think the notion of adolescence in the context of the science classroom. This study is timely given the report "The Status and Quality of Year 11 and 12 Science in Australian Schools" (Goodrum, Druhan & Abbs, 2011) and national curricular changes that are being proposed for science (ACARA, 2009).

Adapting Lyubashevsky's signature schemes to the ring signature setting

Basing signature schemes on strong lattice problems has been a long standing open issue. Today, two families of lattice-based signature schemes are known: the ones based on the hash-and-sign construction of Gentry et al.; and Lyubashevsky’s schemes, which are based on the Fiat-Shamir framework. In this paper we show for the first time how to adapt the schemes of Lyubashevsky to the ring signature setting. In particular we transform the scheme of ASIACRYPT 2009 into a ring signature scheme that provides strong properties of security under the random oracle model. Anonymity is ensured in the sense that signatures of different users are within negligible statistical distance even under full key exposure. In fact, the scheme satisfies a notion which is stronger than the classical full key exposure setting as even if the keypair of the signing user is adversarially chosen, the statistical distance between signatures of different users remains negligible. Considering unforgeability, the best lattice-based ring signature schemes provide either unforgeability against arbitrary chosen subring attacks or insider corruption in log-sized rings. In this paper we present two variants of our scheme. In the basic one, unforgeability is ensured in those two settings. Increasing signature and key sizes by a factor k (typically 80 − 100), we provide a variant in which unforgeability is ensured against insider corruption attacks for arbitrary rings. The technique used is pretty general and can be adapted to other existing schemes.

Continuous disclosure compliance: Does corporate governance matter?

Our study investigates the quality of firms’ continuous disclosure compliance during mandatory continuous disclosure reform, and whether the compliance quality is impacted by corporate governance, using the New Zealand market as the setting. We use a novel coding of different categories of disclosures (nonroutine, non-procedural and internal), which represents the extent of proprietary insider information inherent in disclosures, to evaluate firms’compliance quality. Our findings provide evidence that firms’ compliance quality improved after the reform, and this improvement is inconsistently impacted by corporate gvernance. Our findings provide important implications for regulators in their quest for a superior disclosure regime

Parallel Signcryption

The primary motivation for signcryption was the gain in efficiency when both encryption and signing need to be performed. These two cryptographic operations may be done sequentially either by first encrypt and then sign (EtS) or alternatively, by first sign and then encrypt (StE). Further gains in efficiency can be achieved if encryption and signature are carried out in parallel (E&S). More importantly, however, is that these efficiency gains are complemented by gains in security, i.e., we may use relative weak encryption and signature schemes in order to obtain a “stronger” signcryption scheme. The reader is referred to Chaps. 2 and 3 for a discussion of the different “strengths” of security model (e.g., outsider vs. insider adversaries, two-user vs. multi-user setting).

Parallel authentication and public-key encryption

A parallel authentication and public-key encryption is introduced and exemplified on joint encryption and signing which compares favorably with sequential Encrypt-then-Sign (ɛtS) or Sign-then-Encrypt (Stɛ) schemes as far as both efficiency and security are concerned. A security model for signcryption, and thus joint encryption and signing, has been recently defined which considers possible attacks and security goals. Such a scheme is considered secure if the encryption part guarantees indistinguishability and the signature part prevents existential forgeries, for outsider but also insider adversaries. We propose two schemes of parallel signcryption, which are efficient alternative to Commit-then-Sign-and- Encrypt (Ct&G3&S). They are both provably secure in the random oracle model. The first one, called generic parallel encrypt and sign, is secure if the encryption scheme is semantically secure against chosen-ciphertext attacks and the signature scheme prevents existential forgeries against random-message attacks. The second scheme, called optimal parallel encrypt. and sign, applies random oracles similar to the OAEP technique in order to achieve security using encryption and signature components with very weak security requirements — encryption is expected to be one-way under chosen-plaintext attacks while signature needs to be secure against universal forgeries under random-plaintext attack, that is actually the case for both the plain-RSA encryption and signature under the usual RSA assumption. Both proposals are generic in the sense that any suitable encryption and signature schemes (i.e. which simply achieve required security) can be used. Furthermore they allow both parallel encryption and signing, as well as parallel decryption and verification. Properties of parallel encrypt and sign schemes are considered and a new security standard for parallel signcryption is proposed.

A non-malleable group key exchange protocol robust against active insiders

In this paper we make progress towards solving an open problem posed by Katz and Yung at CRYPTO 2003. We propose the first protocol for key exchange among n ≥2k+1 parties which simultaneously achieves all of the following properties: 1. Key Privacy (including forward security) against active attacks by group outsiders, 2. Non-malleability — meaning in particular that no subset of up to k corrupted group insiders can ‘fix’ the agreed key to a desired value, and 3. Robustness against denial of service attacks by up to k corrupted group insiders. Our insider security properties above are achieved assuming the availability of a reliable broadcast channel.

The Dancer as Reflective Practitioner

The inextricably intimate relationships connecting the dancer, the dance and the self indicate that the practice of dance is inherently a reflective practice of feedback looping. Professional dancers are aware of this in continuing self-critical analyses and reflections for self-improvement, striving for the ever-elusive perfection in performance. The reflective nature of learning dance is, however, less apparent to the student of dance due to the traditional master/apprentice approach to dance training. By making explicit the essentially reflective sequence of processes through which the self becomes the dancer of the dance, the locus of control is shifted towards the dance student, thereby increasing the sense of autonomy and intrinsic motivation for exploration, discovery and improvement of her or his own practice. This study documents the implementation of the 4Rs approach to reflective practice in a university dance training context. Data include reflective observations of dance lessons, and teacher and student reflections on the reflective approach taken in these lessons. Insider and outsider perspectives from students, the dance teacher and external researchers are taken to provide a nuanced understanding of the value of corporeal, visual and verbal reflection in dance for improved performance.

Permissionary work

The Los Angeles-based collaborative duo responds to the community-focused mission of the Center for the Arts Eagle Rock by asking themselves what kinds of invitations they want to extend to others publicly and privately. The resulting works depict various attempts at engagement and include examples that are insider, narcissistic, exclusive, inclusive, and imaginary. This new body of work furthers CamLab’s ongoing investigation into intimacy and how the political becomes personal by making its existing networks palpable and by giving its potential networks form.

Agency problems of corporate philanthropy

Evaluating agency theory and optimal contracting theory views of corporate philanthropy, we find that as corporate giving increases, shareholders reduce their valuation of firm cash holdings. Dividend increases following the 2003 Tax Reform Act are associated with reduced corporate giving. Using a natural experiment, we find that corporate giving is positively (negatively) associated with CEO charity preferences (CEO shareholdings and corporate governance quality). Evidence from CEO-affiliated charity donations, market reactions to insider-affiliated donations, its relation to CEO compensation, and firm contributions to director-affiliated charities indicates that corporate donations advance CEO interests and suggests misuses of corporate resources that reduce firm value.

Review of "English language education across Greater China"; edited by Anwei Feng

I formally learned English from Year Four until the completion of my undergraduate study in China. Because of this personal history, I was keen to review this book and revisit English education in China. The list of contributors to the book includes Anwei Feng (editor) and his colleagues, who play an insider role in English language practice, research, and policy-making in “Greater China”. Greater China according to Feng, can be defined as geographically close, demographically Chinese-dominated, and culturally, economically, and socio-politically interrelated countries and territories where Chinese is either the mother tongue or used as an official language.