DRE-ip : A Verifiable E-Voting Scheme without Tallying Authorities

Nearly all verifiable e-voting schemes require trustworthy authorities to perform the tallying operations. An exception is the DRE-i system which removes this requirement by pre-computing all encrypted ballots before the election using random factors that will later cancel out and allow the public to verify the tally after the election. While the removal of tallying authorities significantly simplifies election management, the pre-computation of ballots necessitates secure ballot storage, as leakage of precomputed ballots endangers voter privacy. In this paper, we address this problem and propose DRE-ip (DRE-i with enhanced privacy). Adopting a different design strategy, DRE-ip is able to encrypt ballots in real time in such a way that the election tally can be publicly verified without decrypting the cast ballots. As a result, DRE-ip achieves end-to-end verifiability without tallying authorities, similar to DRE-i, but with a significantly stronger guarantee on voter privacy. In the event that the voting machine is fully compromised, the assurance on tallying integrity remains intact and the information leakage is limited to the minimum: only the partial tally at the time of compromise is leaked

Focus group views on Prêt à Voter 1.0

This paper discusses the findings of a series of four focus group sessions carried out on a variant of the original Prêt à Voter prototype implementation [2]. The aim of these sessions was to investigate users' ability to use the system, to discover any inadequacies of the system, and to gauge the participants' understanding of its security mechanisms. The groups also discussed general issues around security in election systems

Testing Voters' Understanding of a Security Mechanism Used in Verifiable Voting

Proposals for a secure voting technology can involve new mechanisms or procedures designed to provide greater ballot secrecy or verifiability. These mechanisms may be justified on the technical level, but researchers and voting officials must also consider how voters will understand these technical details, and how understanding may affect interaction with the voting systems. In the context of verifiable voting, there is an additional impetus for this consideration as voters are provided with an additional choice; whether or not to verify their ballot. It is possible that differences in voter understanding of the voting technology or verification mechanism may drive differences in voter behaviour; particularly at the point of verification. In the event that voter understanding partially explains voter decisions to verify their ballot, then variance in voter understanding will lead to predictable differences in the way voters interact with the voting technology. This paper describes an experiment designed to test voters’ understanding of the ‘split ballot’, a particular mechanism at the heart of the secure voting system Prˆet `a Voter, used to provide both vote secrecy and voter verifiability. We used a controlled laboratory experiment in which voter behaviour in the experiment is dependent on their understanding of the secrecy mechanism for ballots. We found that a two-thirds majority of the participants expressed a confident comprehension of the secrecy of their ballot; indicating an appropriate level of understanding. Among the remaining third of participants, most exhibited a behaviour indicating a comprehension of the security mechanism, but were less confident in their understanding. A small number did not comprehend the system. We discuss the implications of this finding for the deployment of such voting systems

Authenticating Binary Text Documents Using a Localising OMAC Watermark Robust to Printing and Scanning

In this paper we propose a new authentication and localisation scheme to produce a watermark which can be embedded in a limited capacity binary text document and that will work in a print and scan environment. The scheme utilises Message Authentication Codes (MAC), specifically OMACs, which create a cryptographic fixed-length summary of a document. An OMAC must be truncated to a form part of our watermark and is used during authentication. The remainder of the watermark is used during localisation. We have created over 2,000,000 watermarks in controlled experiments to evaluate their ability to authenticate a document and localise any changes. In addition, we have embedded an authenticating watermark into seven different documents and authenticated them after printing and scanning

Antiretroviral agents and acid-base balance at delivery of the neonate.

Limited evidence is available regarding antiretroviral (ARV) safety for uninfected infants exposed to these drugs in utero. Our objective was to determine if ARV administered to pregnant women is associated with decreasing umbilical arterial pH and base excess in uninfected infants. A prospective study was conducted on 57 neonates divided into three groups: ZDV group, born to mothers taking zidovudine (N = 20), triple therapy (TT) group, born to mothers taking zidovudine + lamivudine + nelfinavir (N = 25), and control group (N = 12), born to uninfected mothers. Umbilical cord blood was used to determine umbilical artery gases. A test was performed to calculate the sample by comparing means by the unpaired one-tailed t-test, with alpha = 0.05 and beta = 20%, indicating the need for a sample of 18 newborn infants for the study groups to detect differences higher than 20%. The control and ARV groups were similar in gestational age, birth weight, and Apgar scores. Values of pH, pCO2, bicarbonate, and base excess in cord arterial blood obtained at delivery from the newborns exposed to TT were 7.23, 43.2 mmHg, 19.5 mEq/L, and -8.5 nmol/L, respectively, with no significant difference compared to the control and ZDV groups. We conclude that intrauterine exposure to ARV is not associated with a pathological decrease in umbilical arterial pH or base excess. While our data are reassuring, follow-up is still limited and needs to be continued into adulthood because of the possible potential for adverse effects of triple antiretroviral agents