In this paper, we focus on verifiability of predicate encryption. A verifiable predicate encryption scheme guarantees that all legitimate receivers of a ciphertext will obtain the same message upon decryption. While verifiability of predicate encryption might be a desirable property by itself, we furthermore show that this property enables interesting applications. Specifically, we provide two ...

In a finitely repeated principal agent relationship with adverse selection I study (exogenous) interim information that is revealed during a long term relationship. Interim information mitigates adverse selection. Verifiability, measured by the cost of signal manipulation, and the signal’s informativeness determine the use and effectiveness of interim information: Less precise and more manipula...

Anonymity and verifiability are crucial security requirements for voting. Still, they seem to be contradictory, and confusion exists about their precise meanings and compatibility. In this paper, we resolve the confusion by showing that both can be expressed in terms of (un)linkability: while anonymity requires unlinkability of voter and vote, verifiability requires linkability of voters and el...

Dung’s abstract argumentation theory is a widely used formalism to model conflicting information and to draw conclusions in such situations. Hereby, the knowledge is represented by so-called argumentation frameworks (AFs) and the reasoning is done via semantics extracting acceptable sets. All reasonable semantics are based on the notion of conflict-freeness which means that arguments are only j...

We present a symbolic definition of election verifiability for electronic voting protocols. Our definition is given in terms of reachability assertions in the applied pi calculus and is amenable to automated reasoning using the tool ProVerif. The definition distinguishes three aspects of verifiability, which we call individual, universal, and eligibility verifiability. It also allows us to dete...

An electronic voting protocol provides cast-as-intended verifiability if the voter can verify that her encrypted vote contains the voting options that she selected. There are some proposals of protocols with cast-as-intended verifiability in the literature, but all of them have drawbacks either in terms of usability or in terms of security. In this paper, we propose a new voting scheme with cas...

We present a symbolic definition that captures some cases of election verifiability for electronic voting protocols. Our definition is given in terms of reachability assertions in the applied pi calculus and is amenable to automated reasoning using the software tool ProVerif. The definition distinguishes three aspects of verifiability, which we call individual, universal, and eligibility verifi...

Currently, rather secure cryptographic voting protocols providing verifiability exist. However, without adequate usability and abstraction concepts to explain the voting process and, in particular, the verifiability steps, they are not ready for legally binding elections. This holds in particular for remote electronic voting systems because of the absence of poll workers who can support voters ...

We present a formal, symbolic definition of election verifiability for electronic voting protocols in the context of the applied pi calculus. Our definition is given in terms of boolean tests which can be performed on the data produced by an election. The definition distinguishes three aspects of verifiability: individual, universal and eligibility verifiability. It also allows us to determine ...

Belenios is an online voting system that provides a strong notion of election verifiability, where no single party has to be trusted, and security holds as soon either the registrar or server honest. It was formally proved secure, making assumption further ballots are cast on bulletin board after voters verified their ballots. In practice, however, revoting allowed can verify anytime. This gap ...