A Resource-Oriented Blockchain Architecture for Secure Decentralised E-Voting

Blockchain technology is evolving. Since its inception in 2009, it has since progressed to offer flexible public development platforms that are expanding its area of usage past cryptocurrencies and financial applications and into more general digital applications. In particular, blockchain has emerged recently as an interesting alternative to represent digital assets in blockchain environments. Unlike digital objects outside it, blockchain objects can be made unique, traceable, and transferable, with powerful ownership mechanics that make them attractive to integrate into other digital applications. Blockchain tokens can be used by themselves within the digital world to represent unique, ownable digital objects, but these can also be used to mirror physical objects whose ownership in the real world can now be emulated with the cryptographic properties of blockchain tokens. A recently introduced innovative blockchain architecture is of particular interest. The resource-based model for representing digital assets in blockchains uses linear types, a mathematical abstraction used to emulate real-world mechanics in the mathematical domain, to propose a different approach to digital asset representation. The linear type concept has been used in general-purpose languages, such as Rust, but it made its way through the blockchain ecosystem, coalescing in 2020 into two smart contract programming languages and a series of public blockchain protocols implementing the resource-based programming paradigm. Resources inherit the properties of linear type values to represent digital assets in blockchains. Resources emulate real-world assets in the sense that they cannot be copied, only moved, can only exist in one logical location at a time, and their destruction must be explicit in the program and restricted to the asset owner. These properties make resources very attractive for a tokenisation approach to problems. One problem in particular stands out as an ideal candidate for such an approach. Remote electronic voting is an active area of academic research, but that has been notoriously incapable of producing solutions that can be mass adopted. For some decades, research in this field has been limited to using commercial cryptographic techniques to implement security features in evoting systems, towards producing a secure, private, transparent, and verifiable voting system. Blockchain was a disruptive innovation for this field. So much so that academic e-voting research can be split into a pre and post-blockchain era regarding the utilisation of blockchain platforms, tools, and properties in academic proposals. Though the last years have been fruitful, academic research in this field is still largely exploring classic blockchain architectures and, so far, has ignored the resourcebased architecture altogether. The research work conducted in the doctoral process presented in this document covers this knowledge gap. The hypothesis is that resource-based blockchain architectures are suitable to develop secure, private, transparent and verifiable remote e-voting systems with better performance and scalability potential than any of the academic proposals based on classical architectures published so far. The research work presented with this thesis splits into three streams: it begins with a thorough introduction of the resource-based architectural paradigm for blockchain representation of digital assets, with the purpose of providing an application example for this new architecture. The thesis follows with a detailed analysis of the application problem selected, namely, the development of an electronic voting system, with particular emphasis on the state of the art of the blockchain-based proposals towards defining the application scope clearly. The third stream merges the two so far, combining the knowledge retrieved from the resource-based introduction with the system requirements extracted from the e-voting research analysis to provide a proposal, implementation, and analysis of a blockchain-based, resource-based remote e-voting system. This prototype embodies the research work conducted during the doctoral process. It presents the first known implementation of a blockchain-based electronic voting system in a resource-oriented blockchain architecture. The proposal explores the new approach to ownership and the linear-type properties of resources to produce a secure, transparent, private, and scalable system. The resourcebased architecture provides functionalities that allow the implementation of additional features to the system to increase its application scope, such as multiple vote casting, ballot revocation, and ballot delegation capabilities, that provide voters with increased flexibility of utilisation and control over their election options. Finally, this proposal also takes advantage of a transaction cost delegation ability inherited from the blockchain protocol supporting the solution. This feature allows the system to delegate all transactional gas costs to a single entity, such as an election authority, for example, thus making it completely free for use from the perspective of the voter.