Generalised cumulative arrays in secret sharing

Cumulative arrays have played an important role in the early development of the secret sharing theory. They have not been subject to extensive study so far, as the secret sharing schemes built on them generally result in much larger sizes of shares, when compared with other conventional approaches. Recent works in threshold cryptography show that cumulative arrays may be the appropriate building blocks in non-homomorphic threshold cryptosystems where the conventional secret sharing methods are generally of no use. In this paper we study several extensions of cumulative arrays and show that some of these extensions significantly improve the performance of conventional cumulative arrays. In particular, we derive bounds on generalised cumulative arrays and show that the constructions based on perfect hash families are asymptotically optimal. We also introduce the concept of ramp perfect hash families as a generalisation of perfect hash families for the study of ramp secret sharing schemes and ramp cumulative arrays.

Ideal secret sharing schemes from permutations

The work presents a new method for the design of ideal secret sharing. The method uses regular mappings that are well suited for construction of perfect secret sharing. The restriction of regular mappings to permutations gives a convenient tool for investigation of the relation between permutations and ideal secret sharing generated by them.

Lattice-based threshold-changeability for standard CRT secret-sharing schemes

We consider the problem of increasing the threshold parameter of a secret-sharing scheme after the setup (share distribution) phase, without further communication between the dealer and the shareholders. Previous solutions to this problem require one to start off with a non-standard scheme designed specifically for this purpose, or to have secure channels between shareholders. In contrast, we show how to increase the threshold parameter of the standard CRT secret-sharing scheme without secure channels between the shareholders. Our method can thus be applied to existing CRT schemes even if they were set up without consideration to future threshold increases. Our method is a positive cryptographic application for lattice reduction algorithms, and we also use techniques from lattice theory (geometry of numbers) to prove statements about the correctness and information-theoretic security of our constructions.

Lattice-based threshold-changeability for standard Shamir secret-sharing schemes

We consider the problem of increasing the threshold parameter of a secret-sharing scheme after the setup (share distribution) phase, without further communication between the dealer and the shareholders. Previous solutions to this problem require one to start off with a non-standard scheme designed specifically for this purpose, or to have communication between shareholders. In contrast, we show how to increase the threshold parameter of the standard Shamir secret-sharing scheme without communication between the shareholders. Our technique can thus be applied to existing Shamir schemes even if they were set up without consideration to future threshold increases. Our method is a new positive cryptographic application for lattice reduction algorithms, inspired by recent work on lattice-based list decoding of Reed-Solomon codes with noise bounded in the Lee norm. We use fundamental results from the theory of lattices (Geometry of Numbers) to prove quantitative statements about the information-theoretic security of our construction. These lattice-based security proof techniques may be of independent interest.

Nonlinear secret sharing immune against cheating

The paper investigates the design of secret sharing that is immune against cheating (as defined by the Tompa-Woll attack). We examine secret sharing with binary shares and secrets. Bounds on the probability of successful cheating are given for two cases. The first case relates to secret sharing based on bent functions and results in a non-perfect scheme. The second case considers perfect secret sharing built on highly nonlinear balanced Boolean functions.

On cheating immune secret sharing

The paper addresses the cheating prevention in secret sharing. We consider secret sharing with binary shares. The secret also is binary. This model allows us to use results and constructions from the well developed theory of cryptographically strong boolean functions. In particular, we prove that for given secret sharing, the average cheating probability over all cheating vectors and all original vectors, i.e., 1/n 2n ∑c=1...n ∑α∈V n ρc,α , denoted by ρ, satisfies ρ ≥ ½, and the equality holds if and only if ρc,α satisfies ρc,α= ½ for every cheating vector δc and every original vector α. In this case the secret sharing is said to be cheating immune. We further establish a relationship between cheating-immune secret sharing and cryptographic criteria of boolean functions.This enables us to construct cheating-immune secret sharing.

One-stop shopping : some notes on the concept and some Australian initiatives

This paper aims to review the notion of the one-stop shop, particularly as it has developed in Australia. It has three main components. The first focuses on a significant initiative taken by the Coombs Royal Commission on Australian Government Administration as a form of action research in the mid-1970s. The second highlights the associated work on access theory by the late Bernard Schaffer and his associates and explains why this work was of fundamental importance for the development of the idea of the one-stop shop. The third deals with subsequent Australian understandings and a pp lications of the idea.

Dalby Shopping Precinct Survey Report : Consumer Attitudes towards Proposed Extended Trading Hours at Dalby

Data was collected to measure shopper’s attitudes toward the proposed Sunday and limited public holiday trading in Dalby. Survey questionnaires were conducted between 29th August to 31st August at Coles Dalby and Dalby Shoppingtown Plaza. In total, 150 respondents participated in the survey. Overall, the findings suggest that most respondents, especially males, couples with children, fulltime workers and those under the age of 49 years, embrace the proposed Sunday and limited holiday trading in Dalby. While there are concerns over increasing competition for smaller retailers who already trade on Sundays, a majority of respondents indicated it would suit their lifestyle, be convenient, provide more jobs, increase trade for smaller retailers within the area, reduce queues and congestion observed on Saturdays. The majority of those shoppers that indicated they currently did some shopping on a Sunday reported they would continue to support smaller retailers who currently trade on Sundays and some public holidays, if changes came about. Those opposed to changes to trading hours indicated a belief that existing trading hours were sufficient. Most people indicated the proposed extension of trading hours would not harm the community or have a negative, detrimental effect on themselves or their family. The main findings presented in the report are as follows: - 96.8% of respondents surveyed reported to be local, permanent residents of Dalby. - Residents of Dalby visited shopping centres and stores on average 2.8 times per week. This frequency is proportionately higher than the average Australian shopping behaviour at 2.5 times per week (Roy Morgan Supermarket Monitor). - It was determined that weekday evenings (after 5 pm) were the busiest times for shopping, with Saturday the next most popular day to shop. - 68% of respondents support the proposal of the extended trading hours at supermarkets, department stores and the shopping centre in Dalby, 26% oppose and 6% are unsure. - 90% of the respondents agreed that residents of Dalby should be allowed the same choice as other regional towns and cities in supporting/opposing changes to trading hours. The remaining 10% expressed a disagreement. - A larger percentage of males supported the proposal for Sunday and limited holiday trading. Of all the males surveyed, 80% were in support, 15% were opposed and 5% unsure. 60% of female respondents support the proposal, while 33% oppose it and 5% were unsure. - The highest percentage of support exists in fulltime workers with 90% of those respondents supporting the proposal. - In contrast, the lowest percentage of support was found in the non-working (retired/unemployed) respondents, where 67% opposed the application. - It was noted that 71% of respondents employed casually also indicated opposition against proposed changes. Further questioning identified an underlying concern from casually employed persons that Sunday trade would force them onto Sunday work rosters. - 92% of shared households expressed support for Sunday and limited public holiday trading, while 83% of both couples with children and single parent with children at home also supported the application. - 72% of the respondents often find it necessary to do some grocery shopping in Dalby on a Sunday. 76% of shoppers who indicated they already undertook some shopping on Sunday, indicated would continue to shop and support smaller retailers. - Of the respondents surveyed, 44% have travelled outside of Dalby on a Sunday to shop. This indicates that such residents find it necessary to undertake some shopping on a Sunday and in order to do so, drive an hour to Toowoomba in order to access a range of retailers. - The most cited reasons for supporting Sunday and limited public holiday trade were; ‘More choice about when I shop and that is convenient’ (69%), ‘Sunday trade will create job opportunities’ (71%), ‘Sunday trade will be helpful when preparing school lunches and getting ready for the working week’ (62%), and ‘Sunday trade will reduce shopping congestion during peak shopping periods’ (62%) - The most cited reasons for opposing the proposed changes are that ‘Sunday trade may increase competition for small retailers who already trade on Sunday’ (41%), ‘Shops are already open 6 days a week which is enough’ (31%), and ‘Sunday is a day of rest or a religious day and shopping should not be allowed’ (23%). - 97% of respondents indicated they would not change their sporting or social commitment if changes to trading hours were implemented.

Mt Isa Shopping Precinct Survey Report : Consumer Attitudes towards Proposed Extended Trading Hours at Mt Isa

Data was collected to measure shopper’s attitudes toward the proposed Sunday and limited public holiday trading in Mt Isa. Survey questionnaires were conducted between 15th August to 17th August at Kmart Plaza, Woolworths, Miles St. and Mt Isa Plaza. In total, 300 respondents participated in the survey. Overall, the findings suggest that most respondents, especially males, couples with children and fulltime workers, embrace the proposed Sunday and limited holiday trading in Mt Isa. While there are concerns over increasing competition for smaller retailers who already trade on Sundays, a majority of respondents indicated it would suit their lifestyle, be convenient, provide more jobs, increase trade for smaller retailers within the area, reduce queues and congestion, and offer a less expensive grocery shopping. The majority of those shoppers that indicated they currently did some shopping on a Sunday reported they would continue to support smaller retailers who currently trade on Sundays and some public holidays, if changes came about. Those opposed to changes to trading hours also indicated a belief that existing trading hours were sufficient. Most people indicated the proposed extension of trading hours would not harm the community or have a negative, detrimental effect on themselves or their family. The main findings presented in the report are as follows: - 96% of respondents surveyed reported to be local, permanent residents of Mt Isa. - Residents of Mt Isa visited shopping centres and stores on average 2.4 times per week. This mirrors the average Australian shopping behaviour at 2.5 times per week (Roy Morgan Supermarket Monitor) - It was determined that Saturday was the busiest day for shopping with a majority of respondents indicating they visited stores on that day of the week. - 71% of respondents support the proposal of extended trading hours at shopping centres in Mt Isa, 25% oppose and 4% are unsure. - 87% of the respondents agreed that residents of Mt Isa should be allowed the same choice as other regional towns and cities in supporting/opposing changes to trading hours. The remaining 13% expressed a disagreement. - A larger percentage of males supported the proposal for Sunday and limited holiday trading. Of all the males surveyed, 81% were in support, 17% were opposed and 2% unsure. By contrast, 64% of female respondents support the proposal, while 31% oppose it and 5% are unsure. - The highest percentage of support exists in fulltime workers with 85% of those respondents supporting the proposal. In contrast, the lowest percentage of support was found in the non-working respondents, where 62% opposed the application. - 78% of couples living with children at home expressed support for Sunday and limited public holiday trading, while 60% of couples without children also supported the application. - Of the respondents surveyed, virtually none (less than 1%) have travelled outside of Mt Isa on a Sunday to shop. This indicates that due to the remote and isolated location of this town, residents do not have the option to travel reasonable distances in order to access a range of retailers. - 70% of the respondents often find it necessary to do some grocery shopping in Mt Isa on a Sunday. - Convenience is cited as the major reason for support (79%) followed by lifestyle (75%). - The most cited reasons for supporting ‘it would be convenient’ (81%), ‘It may create more jobs’ (77%), ‘It may reduce congestion during busy shopping periods’ (74%, and ‘It would make it easier for working families with kids’ (74%). - The most cited reasons for opposing the proposed changes are that ‘It will disadvantage smaller businesses’ (44%), ‘It is unnecessary’ (29%). - 72% of shoppers who indicated they already undertook some shopping on Sunday, indicated would continue to shop and support smaller retailers. - 98% of respondents indicated they would not change their sporting or social commitment if changes to trading hours were implemented.

ACE research vignette 037 : Bill Gates’ mug shot : Is there a secret link between rule-breaking, crime, and entrepreneurship?

This series of research vignettes is aimed at sharing current and interesting research findings from international entrepreneurship researchers. In this vignette, Dr. Martin Obschonka, considers the relationship between entrepreneurship and rule-breaking.

Dual compressible hybrid quantum secret sharing schemes based on extended unitary operations

A crucial issue with hybrid quantum secret sharing schemes is the amount of data that is allocated to the participants. The smaller the amount of allocated data, the better the performance of a scheme. Moreover, quantum data is very hard and expensive to deal with, therefore, it is desirable to use as little quantum data as possible. To achieve this goal, we first construct extended unitary operations by the tensor product of n, n ≥ 2, basic unitary operations, and then by using those extended operations, we design two quantum secret sharing schemes. The resulting dual compressible hybrid quantum secret sharing schemes, in which classical data play a complementary role to quantum data, range from threshold to access structure. Compared with the existing hybrid quantum secret sharing schemes, our proposed schemes not only reduce the number of quantum participants, but also the number of particles and the size of classical shares. To be exact, the number of particles that are used to carry quantum data is reduced to 1 while the size of classical secret shares also is also reduced to l−2 m−1 based on ((m+1, n′)) threshold and to l−2 r2 (where r2 is the number of maximal unqualified sets) based on adversary structure. Consequently, our proposed schemes can greatly reduce the cost and difficulty of generating and storing EPR pairs and lower the risk of transmitting encoded particles.

Secret Millionares Club

Secret Millionaires Club is an animated series of 26 webisodes featuring Warren Buffett (CEO and largest shareholder of Berkshire Hathaway) as a secret mentor to a group of kids who learn practical life lessons during fun-filled adventures in business.

Customer agility, smart shopping apps and their implications: Customer relationship management systems in the digital age

This thesis examines the complementarities and vulnerabilities of customer connectivity that contemporary firms achieved through ubiquitous digital technologies. Taking the example of deployment of smart shopping apps to connect with consumers in the context of Australian retail, the study examines how such customer connectivity positively influences firm performances through firm's customer agility whilst creating implications for firms' digital business strategy through altered customer cognitions. Employing Oliver's (1977) Expectation Confirmation Theory, this study empirically tests a conceptual model involving digital connectivity, digital expectations, experiences and satisfaction of the customers who uses smart shopping apps in Australian consumer retail.