Pseudo-Code Algorithms for Verifiable Re-Encryption Mix-Nets

Implementing the shuffle proof of a verifiable mix-net is one of the most challenging tasks in the implementation of an electronic voting system. For non-specialists, even if they are experienced software developers, this task is nearly impossible to fulfill without spending an enormous amount of resources into studying the necessary cryptographic theory. In this paper, we present one of the existing shuffle proofs in a condensed form and explain all the necessary technical details in corresponding pseudo-code algorithms. The goal of presenting the shuffle proof in this form is to make it accessible to a broader audience and to facilitate its implementation by non-specialists

How to Store some Secrets

This paper introduces a special type of symmetric cryptosystem called multi-encryption scheme. It allows users to encrypt multiple plaintexts into a single ciphertext. Each plaintext is protected with its own secret key, meaning that they can be decrypted individually by applying the decryption function with the corresponding key to the ciphertext. Compared to encrypting the ciphertexts one-by-one using a standard symmetric cryptosystem, the main advantage of using a multi-encryption scheme is the no-search property, which guarantees that knowing the key is sufficient for decrypting a single plaintext. We show how to construct a multi-encryption scheme based on polynomials over finite fields. A possible application area is coercion-resistant electronic voting. To ensure a strong form of privacy, voters are equipped with multiple fake credentials, which are indistinguishable from the proper one. While theoretically sound, this requires a voter to perfectly recall multiple lengthy random numbers, and to know which of them is the proper one. To ensure 100\% recall, users need to manage these numbers and keep them secret. A multi-encryption scheme is an elegant solution for this problem

Usable Verifiable Secrecy-Preserving E-Voting

In this paper we propose the usage of QR-Codes to enable usable veriable e-voting schemes based on code voting. The idea { from a voter\u27s perspective { is to combine code voting proposed by Chaum with the cast-as-intended verication mechanism used e.g. in Switzerland (using a personal initialization code, return codes per option, a conrmation code and a nalisation code); while all codes to be entered into the e-voting system by voters are available as QR-Code (i.e. one personalised QR voting code per voting option and one personal conrmation QR-Code). We conduct a user study to evaluate the usability and user experience of such an approach: both the code sheets and the election webpage are based on usability research in this area but adopted for our idea. As our proposal performs good wrt. usability, we discuss how such usable front-ends enable more secure e-voting systems in respect to end-to-end veriability and vote secrecy

Towards A Practical JCJ / Civitas Implementation

Internet voting continues to enjoy wide interest from both research and practice. Among the Internet voting schemes developed over the last decades, JCJ / Civitas stands out from the masses due to its innovative approach to resist voter coercion. To achieve its ambitious goal, the scheme builds upon particularly restrictive assumptions and an abstract credential handling rendering the scheme impractical for real-world use. At ARES 2012, Neumann and Volkamer presented a proposal which implements several of these assumptions (voter-side assumptions) and the credential handling by the use of smart cards. While addressing these practical shortcomings of JCJ / Civitas, their proposal did not take performance into account, and accordingly its performance has not been evaluated. In the present work, we revise the ARES proposal from a performance perspective in a security-invariant manner. Based on the herein proposed revisions, we are able to conclude that the revised ARES proposal is feasible to be used in real-world elections