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Digitization of electoral processes depends on confident systems that produce verifiable evidence. The design and implementation of voting systems has been widely studied in prior research, bringing together expertise in many fields. Switzerland is organized in a federal, decentralized structure of independent governmental entities. Thus, its decentralized structure is a real-world example for implementing an electronic voting system, where trust is distributed among multiple authorities.This work outlines the design and implementation of a blockchainbased electronic voting system providing cast-as-intended verifiability. The generation of non-interactive zero-knowledge proofs of knowledge enables every voter to verify the encrypted vote, while maintaining the secrecy of the ballot. The Public Bulletin Board (PBB) is a crucial component of every electronic voting system, serving as a publicly verifiable log of communication and ballots -here a blockchain is used as the PBB. Also, the required cryptographic operations are in linear relation to the number of voters, making the outlined system fit for large-scale elections.

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Distributed Denial-of-Service (DDoS) attacks are one of the major causes of concerns for communication service providers. When an attack is highly sophisticated and no countermeasures are available directly, sharing hardware and defense capabilities become a compelling alternative. Future network and service management can base its operations on equally distributed systems to neutralize highly distributed DDoS attacks. A cooperative defense allows for the combination of detection and mitigation capabilities, the reduction of overhead at a single point, and the blockage of malicious traffic near its source. Main challenges impairing the widespread deployment of existing cooperative defense are: (a) high complexity of operation and coordination, (b) need for trusted and secure communications, (c) lack of incentives for service providers to cooperate, and (d) determination on how operations of these systems are affected by different legislation, regions, and countries. The cooperative Blockchain Signaling System (BloSS) defines an effective and alternative solution for security management, especially cooperative defenses, by exploiting Blockchains (BC) and Software-Defined Networks (SDN) for sharing attack information, an exchange of incentives, and tracking of reputation in a fully distributed and automated fashion. Therefore, BloSS was prototyped and evaluated through a global experiment, without the burden to maintain, design, and develop special registries and gossip protocols.

is crucial to protect BP against present and future adversaries, thus, not relying on computational intractability.However, REV schemes often apply cryptographic protocols based on Mixnets or Homomorphic Encryption, which rely on hardness assumptions to achieve BP [27]. Thus, Unconditional BP (UP) does not assume computational intractability and eliminates the need for Trusted Third Parties (TTP) [36]. Minimizing trust assumptions and removing the reliance on TTPs for specific tasks within the voting process is a fundamental argument for decentralized voting systems, e.g., for voting in a consortium of industry participants. Instead of relying on TTPs, the UP-based REV system can be fully decentralized. Since most prior work on REV does not achieve UP, they rely on a TTP or base their privacy on a secret shared between multiple trusted entities [36].AEternum's voting scheme provides UP and does not rely on a single trusted authority [36]. In order to achieve UP, the deployment of a decentralized PBB is required. Distributed Ledgers (DL) offer a suitable approach to deploy a Decentralized PBB (DPBB) to achieve such a distribution of trust among authorities [29]. DLs are tamper-proof and immutable, replicate data securely, making them ideal for storing ballots that should not be manipulated by anyone [30].This paper proposes AEternum, the first DL-based REV system combining a voting scheme with UP and a public permissioned DL, which serves as a DPBB. AEternum's voting scheme is based on Non-Interactive Zero-Knowledge Proofs (NIZKP) [36]. UP holds under the assumption of the existence of a PBB and an anonymous channel [37]. Furthermore, the trust assumptions do not impact UP, but are fundamental for verifiability and correctness i.e., trusted authorities are required for fairness. For instance, homomorphic threshold encryption is used to disallow trend analysis during an open voting period. Computational intractability assumptions are only relevant during the voting period to prevent the creation of invalid votes [36].The remainder of the paper is organized as follows. While essential definitions are presented in Section II, Section III discusses AEternum's system design followed by the implementation details in Section IV. Section V renders the discussion, Section VI outlines the security analysis and VII the evaluation. Finally, Section IX draws conclusions and outlines future work.Abstract-Remote Electronic Voting (REV) systems allow voters to cast their votes in an uncontrolled, distributed environment. At the same time, the REV system must provide ballot privacy and verifiability of the final tally. Research has proposed REV schemes offering ballot privacy based on computational intractability assumptions, but only a few provide Unconditional Privacy (UP).Therefore, this work proposes AEternum, a REV system with a voting scheme providing UP. AEternum does not require trust in a central authority, nor does it assume computational intractability of an underlying mathematical problem to provide UP. To satisfy UP's...