An analysis of the RC4 family of stream ciphers against algebraic attacks

To date, most applications of algebraic analysis and attacks on stream ciphers are on those based on lin- ear feedback shift registers (LFSRs). In this paper, we extend algebraic analysis to non-LFSR based stream ciphers. Specifically, we perform an algebraic analysis on the RC4 family of stream ciphers, an example of stream ciphers based on dynamic tables, and inves- tigate its implications to potential algebraic attacks on the cipher. This is, to our knowledge, the first pa- per that evaluates the security of RC4 against alge- braic attacks through providing a full set of equations that describe the complex word manipulations in the system. For an arbitrary word size, we derive alge- braic representations for the three main operations used in RC4, namely state extraction, word addition and state permutation. Equations relating the inter- nal states and keystream of RC4 are then obtained from each component of the cipher based on these al- gebraic representations, and analysed in terms of their contributions to the security of RC4 against algebraic attacks. Interestingly, it is shown that each of the three main operations contained in the components has its own unique algebraic properties, and when their respective equations are combined, the resulting system becomes infeasible to solve. This results in a high level of security being achieved by RC4 against algebraic attacks. On the other hand, the removal of an operation from the cipher could compromise this security. Experiments on reduced versions of RC4 have been performed, which confirms the validity of our algebraic analysis and the conclusion that the full RC4 stream cipher seems to be immune to algebraic attacks at present.

Theorizing about board governance of nonprofit organizations : surveying the landscape

Leading scholars on nonprofit governance have urged that future research be more informed by theory in order to promote more rigorous analysis. The aim of this paper is to survey the major theories on board governance, including those based in the disciplines of economics, management, sociology, psychology, politics, history and theology, in order to respond to this challenge. In addition, the relevance of these theories to a critical set of board behaviors - that is, how boards monitor, judge and influence organizational performance - is examined. Gaps in the theoretical literature are identified, and implications for public policy are explored. We conclude that a multi-theory and multi-disciplinary perspective is needed if research on governance of nonprofit organizations is to be complete in scope, rich in content, and relevant.

Developing new alliances in higher education leadership and governance : autopoietic application of the “arts” creative capacities

This paper, underpinned by a framework of autopoietic principles of creativity/innovation and leadership/governance, argues that open forms of creativity in ‘arts’ provide opportunity for impact upon concepts of development, leadership and governance. The alliance of creativity and governance suggests that by examining various understandings of artistic experiences, readers may perceive new understandings of alliance, application and assessment of such experiences. This critical understanding would include assessing whether such experience supports people changing their aspirations as they become what they want to be. Such understanding may also suggest that different applications of the creative capacity of the ‘arts’ offers relevance in alleged ‘non-creative’ areas of academe, particularly in areas of management, leadership and governance. This alliance also offers the possibility of new staff development programs that facilitate learning and building of individual capacity, as well as facilitate congruent development process and policy, particularly within academic organisational structures.

Twelve-month effectiveness of a parent-led, family-focused weight-management program for prepubertal children : a randomized, controlled trial

BACKGROUND Parenting-skills training may be an effective age-appropriate child behavior-modification strategy to assist parents in addressing childhood overweight. OBJECTIVE Our goal was to evaluate the relative effectiveness of parenting-skills training as a key strategy for the treatment of overweight children. DESIGN The design consisted of an assessor-blinded, randomized, controlled trial involving 111 (64% female) overweight, prepubertal children 6 to 9 years of age randomly assigned to parenting-skills training plus intensive lifestyle education, parenting-skills training alone, or a 12-month wait-listed control. Height, BMI, and waist-circumference z score and metabolic profile were assessed at baseline, 6 months, and 12 months (intention to treat). RESULTS After 12 months, the BMI z score was reduced by ∼10% with parenting-skills training plus intensive lifestyle education versus ∼5% with parenting-skills training alone or wait-listing for intervention. Waist-circumference z score fell over 12 months in both intervention groups but not in the control group. There was a significant gender effect, with greater reduction in BMI and waist-circumference z scores in boys compared with girls. CONCLUSION Parenting-skills training combined with promoting a healthy family lifestyle may be an effective approach to weight management in prepubertal children, particularly boys. Future studies should be powered to allow gender subanalysis.

Environmental Governance for Biodiversity

Effective environmental governance is hampered by the continuing presumption of the state as central actor in the domestic and international political contexts. Over the last 20 years, the traditional 'Westphalian' conception of the sovereign state has come under increasing pressure not only in theory, but also in practice, as evidenced by the increasing importance attributed to the participation of quasi-government and non-government actors in decision-making in domestic and international political issues. This paper is a contribution to the on-going debate about the meaning of effective environmental governance by mapping out a post-Westphalian conception of governance. In particular, it defines governance in relation to the protection of biodiversity; highlights obstacles to effective governance in this area, and discusses forming environmental management plans and environmental governance regimes to implement them. The final section of the paper suggests seven directions for ensuring the realisation of effective environmental governance.

Family-focused weight management program for five- to nine-year-olds incorporating parenting skills training with healthy lifestyle information to support behaviour modification

his case study aims to describe how general parenting principles can be used as part of parent-led, family-focused child weight management that is in line with current Australian Clinical Practice Guidelines. A parent-led, family-focused child weight management program was designed for use by dietitians with parents of young children (five- to nine-year-olds). The program utilises the cornerstones of overweight treatment: diet, activity, behaviour modification and family support delivered in an age-appropriate, family-focused manner. Parents participate in 16 sessions (4 parenting-focused, 8 lifestyle-focused and 4 individual telephone support calls) conducted weekly, fortnightly then monthly over six months. This case study illustrates how a family used the program, resulting in reduced degree of overweight and stabilised waist circumference in the child over 12 months. In conclusion, linking parenting skills to healthy family lifestyle education provides an innovative approach to family-focused child weight management. It addresses key Australian Clinical Practice Guidelines, works at the family level, and provides a means for dietitians to easily adopt age-appropriate behaviour modification as part of their practice.