Search

Electronic voting and counting are increasingly common and have been adopted in a number of Australian jurisdictions. Unfortunately, there is evidence that e-voting systems lack transparency. At present there are reasonable solutions for poll-site e-voting but none for remote paperless Internet voting. Although there are reasonable methods for statistical audits of electronically counted election results, Australian elections do not use them. The authors argue that a purposive approach should be taken to relevant electoral laws to ensure that genuine scrutiny of electronic electoral processes can be undertaken. This would require the source code and the voting data to be made available for testing. The authors recommend a number of legislative reforms to ensure the verifiability of e-voting. These reforms need to be undertaken to ensure that Australian elections are accurate, and consistent with the constitutional requirement of direct choice by electors. [ABSTRACT FROM AUTHOR]

The single transferable vote (STV) is a system of preferential voting for multiseat elections. Each ballot cast by a voter is a (potentially partial) ranking over a set of candidates. No techniques currently exist for computing the margin of victory (MOV) in STV elections. The MOV is the smallest number of ballot manipulations (changes, additions, and deletions) required to bring about a change in the set of elected candidates. Knowing the MOV gives insight into how much time and money should be spent on auditing the election, and whether uncovered mistakes (such as ballot box losses) throw the election result into doubt—requiring a costly repeat election—or can be safely ignored. We present algorithms for computing lower and upper bounds on the MOV in STV elections. In small instances, these algorithms are able to compute exact margins. [ABSTRACT FROM AUTHOR]

Most security protocols appearing in the literature make use of cryptographic primitives that assume that the participants have access to some sort of computational device. However, there are times when there is need for a security mechanism to evaluate some result without leaking sensitive information, but computational devices are unavailable. We discuss here various protocols for solving cryptographic problems using everyday objects: coins, dice, cards, and envelopes. [ABSTRACT FROM AUTHOR]

Introduction: Sharing of health data for secondary uses such as research and public policy development is common. There are many potential benefits, but also risks if information about an individual's health record can be inferred. Studies show cautious willingness amongst the public to share health data for beneficial purposes, as long as they are confident in their data privacy and security. There has been relatively little research into whether the technical guarantees of privacy-preserving technologies are well understood by people asked to consent to sharing their data.Objectives: We sought to assess how accurately people understood the effectiveness of techniques for protecting the privacy of shared health data.Methods: We designed an online survey describing a data-sharing scenario motivated by medical research where data could be shared: raw (including identifiers), de-identified (using k-anonymity), aggregated, and differential privacy applied to aggregated data. Respondents were asked about willingness to share their data, and how likely it was that they could be identified. They were also asked for the meaning of 'de-identified' and whether they would agree to sharing information for 'not solely commercial' purposes, thus mirroring the consent language used by Australia's My Health Record system.Results: Our findings revealed substantial tolerance for researcher use of health data with consistent preference to share data when better privacy-preserving techniques were employed. This was not entirely consistent as slight preference was shown for aggregated data over differential privacy, despite differential privacy being objectively more secure. We conjecture this was because differential privacy and its benefits were not well understood. Similarly, respondents showed no consistent understanding of the term 'de-identified', indicating that this needs to be carefully defined in contexts that seek consent. Finally, many respondents who indicated a willingness to share for purposes that were 'not solely commercial' nevertheless rejected at least some specific scenarios that mixed research and commercial objectives, again indicating a possible gap in their understanding of the terms.Conclusions: We found overall preference for better privacy protection of data as a precondition for secondary use, but limitations in respondents' understanding of key terminology and the differing privacy guarantees of available techniques. Further effort is needed to word secondary data use consent policies to ensure public understanding of commonly used terms and methods, if genuinely informed consent for data sharing is to be gained. [ABSTRACT FROM AUTHOR]

Abstract: We prove properties of a process calculus that is designed for analysing security protocols. Our long-term goal is to develop a form of protocol analysis, consistent with standard cryptographic assumptions, that provides a language for expressing probabilistic polynomial-time protocol steps, a specification method based on a compositional form of equivalence, and a logical basis for reasoning about equivalence. The process calculus is a variant of CCS, with bounded replication and probabilistic polynomial-time expressions allowed in messages and boolean tests. To avoid inconsistency between security and nondeterminism, messages are scheduled probabilistically instead of nondeterministically. We prove that evaluation of any process expression halts in probabilistic polynomial time and define a form of asymptotic protocol equivalence that allows security properties to be expressed using observational equivalence, a standard relation from programming language theory that involves quantifying over all possible environments that might interact with the protocol. We develop a form of probabilistic bisimulation and use it to establish the soundness of an equational proof system based on observational equivalences. The proof system is illustrated by a formation derivation of the assertion, well-known in cryptography, that El Gamal encryption''s semantic security is equivalent to the (computational) Decision Diffie–Hellman assumption. This example demonstrates the power of probabilistic bisimulation and equational reasoning for protocol security. [Copyright &y& Elsevier]