Vote buying revisited: implications for receipt-freeness

In this paper, we analyse the concept of vote buying based on examples that try to stretch the meaning of the concept. Which ex- amples can still be called vote buying, and which cannot? We propose several dimensions that are relevant to qualifying an action as vote buy- ing or not. As a means of protection against vote buying and coercion, the concept of receipt-freeness has been proposed. We argue that, in or- der to protect against a larger set of vote buying activities, the concept of receipt-freeness should be interpreted probabilistically. We propose a general definition of probabilistic receipt-freeness by adapting existing definitions of probabilistic anonymity to voting

Coercion-Resistant Hybrid Voting Systems

Abstract: This paper proposes hybrid voting systems as a solution for the vote buying and voter coercion problem of electronic voting systems. The key idea is to allow voters to revoke and overrule their electronic votes at the polling station. We analyze the potential and pitfalls of such revocation procedures and give concrete recommendations on how to build a hybrid system offering coercion-resistance based on this feature. Our solution may be of interest to governments, which aim at integrating paper-based and electronic voting systems rather than replacing the former by the latter.

Natural Strategic Abilities in Voting Protocols

Security properties are often focused on the technological side of the system. One implicitly assumes that the users will behave in the right way to preserve the property at hand. In real life, this cannot be taken for granted. In particular, security mechanisms that are difficult and costly to use are often ignored by the users, and do not really defend the system against possible attacks. Here, we propose a graded notion of security based on the complexity of the user's strategic behavior. More precisely, we suggest that the level to which a security property $\varphi$ is satisfied can be defined in terms of (a) the complexity of the strategy that the voter needs to execute to make $\varphi$ true, and (b) the resources that the user must employ on the way. The simpler and cheaper to obtain $\varphi$, the higher the degree of security. We demonstrate how the idea works in a case study based on an electronic voting scenario. To this end, we model the vVote implementation of the \Pret voting protocol for coercion-resistant and voter-verifiable elections. Then, we identify "natural" strategies for the voter to obtain receipt-freeness, and measure the voter's effort that they require. We also look at how hard it is for the coercer to compromise the election through a randomization attack

LNCS

Composable notions of incoercibility aim to forbid a coercer from using anything beyond the coerced parties’ inputs and outputs to catch them when they try to deceive him. Existing definitions are restricted to weak coercion types, and/or are not universally composable. Furthermore, they often make too strong assumptions on the knowledge of coerced parties—e.g., they assume they known the identities and/or the strategies of other coerced parties, or those of corrupted parties— which makes them unsuitable for applications of incoercibility such as e-voting, where colluding adversarial parties may attempt to coerce honest voters, e.g., by offering them money for a promised vote, and use their own view to check that the voter keeps his end of the bargain. In this work we put forward the first universally composable notion of incoercible multi-party computation, which satisfies the above intuition and does not assume collusions among coerced parties or knowledge of the corrupted set. We define natural notions of UC incoercibility corresponding to standard coercion-types, i.e., receipt-freeness and resistance to full-active coercion. Importantly, our suggested notion has the unique property that it builds on top of the well studied UC framework by Canetti instead of modifying it. This guarantees backwards compatibility, and allows us to inherit results from the rich UC literature. We then present MPC protocols which realize our notions of UC incoercibility given access to an arguably minimal setup—namely honestly generate tamper-proof hardware performing a very simple cryptographic operation—e.g., a smart card. This is, to our knowledge, the first proposed construction of an MPC protocol (for more than two parties) that is incoercibly secure and universally composable, and therefore the first construction of a universally composable receipt-free e-voting protocol

Expressing Receipt-Freeness and Coercion-Resistance in Logics of Strategic Ability: Preliminary Attempt

ABSTRACT Voting is a mechanism of utmost importance to social processes. In this paper, we focus on the strategic aspect of information security in voting procedures. We argue that the notions of receipt-freeness and coercion resistance are underpinned by existence (or nonexistence) of a suitable strategy for some participants of the voting process. In order to back the argument formally, we provide logical "transcriptions" of the informal intuitions behind coercion-related properties that can be found in the existing literature. The transcriptions are formulated in the modal game logic ATL * , well known in the area of multi-agent systems

XML Based Security Model for Enhancing the Integrity and the Privacy of E-Voting Systems

As the world is becoming more technological, using electronic voting could be very beneficial in elections rather using traditional paper-based election schemes. However, there are many security related issues that can cause significant problems in electronic voting (e-voting). Violating voters’ privacy or integrity of ballots would definitely cause serious problems with the entire election process. People may refuse to accept the electronic form of elections. Existing e-voting systems use sophisticated but inefficient, and expensive techniques to satisfy the security requirements of e-voting. Therefore, most of small and mid-size electoral populations cannot employ e-voting systems in their elections and experience remarkable benefits of e-voting. In this thesis, a new electronic voting approach is proposed using extensible markup language (XML) to verify and secure the integrity as well as to preserve the privacy of the voters. The evaluation results of this thesis show that the new approach is an implementation friendly, efficient, and also cost-effective approach to safeguard integrity and privacy related security requirements of e-voting systems for small and mid-size electoral populations