A Survey of Techniques for Improving Security of GPUs

Graphics processing unit (GPU), although a powerful performance-booster, also has many security vulnerabilities. Due to these, the GPU can act as a safe-haven for stealthy malware and the weakest `link' in the security `chain'. In this paper, we present a survey of techniques for analyzing and improving GPU security. We classify the works on key attributes to highlight their similarities and differences. More than informing users and researchers about GPU security techniques, this survey aims to increase their awareness about GPU security vulnerabilities and potential countermeasures

Publicity verifiable ranked choice online voting system

Elections conducted on paper consume a lot of resources and contribute to the destruction of forests, which leads to climate deterioration. Moreover, such election process can make it difficult for some people to vote and it often leads to doubts in the validity of counting, in people submitting multiple votes, in ineligible people voting. In several well-known previous examples, doubts in the validity of paper elections lead to the need of recounting and even court battles to decide the validity of the outcome. Having a way to vote online could be an easier and more reliable solution. However, secure and verifiable methods of online voting need to be developed to achieve this. Recent online voting experiences in countries such as the United States, India and Brazil demonstrated that further research is needed to improve security guarantees for future elections, to ensure the confidentiality of votes and enable the verification of their integrity and validity. Electronic voting, to be successful, requires a more transparent and secure approach, than the approach that is offered by current electronic voting protocols. Advanced security methods are necessary to introduce effective online voting in the whole world. Currently, most online voting systems are centralized, which means that they involve central tallying authorities to take responsibility for verifying, tallying and publishing the final outcome of the election. These previous systems always assume that their central authorities are honest. Otherwise, the published final outcome cannot be trusted. The aim of our new research is to propose and investigate a decentralized ranked choice online voting systems, which never rely on any third party (such as tallying authorities), thereby significantly increasing the confidence and trust of the voters. The thesis presents several publicly verifiable online voting systems and indicates the processing steps and stages in the development of a publicity verifiable online voting system from centralized to semi-decentralized, to fully decentralized. By using Homomorphic cryptosystem, proof of zero knowledge and Blockchain technology, the proposed system in this thesis can achieve the following: (1) Flexible voting mechanism: voters can easily rank all candidates; (2) Publicity verifiable: the whole election procedure is transparent and verifiable by voters; (3) Self-tallying: the final outcome of the election can be computed by any individual voter; and (4) Fully decentralized: no tallying authority (or any other trusted third party) involved at all. The proposed systems presented in this thesis include protocols developed on Blockchain technology. The technology that is used as the basis for a secure online voting system is ``smart contract over Blockchain'', which offers a factor of the integrity of votes and has not been deeply studied in Blockchain technologies to date. The proposed voting protocols ensure confidentiality and preserve the voters' privacy while keeping the election procedures transparent and secure. The underlying Blockchain protocol has not been modified in any way, the voting scheme proposed merely offers an alternative use case of the protocol at hand, which could be presented as the basis for voting systems using Blockchain with further development of the underlying Blockchain protocols