Abstract
Cloud storage allows users to remotely store their data, giving access anywhere and to anyone with an Internet connection. The accessibility, lack of local data maintenance and absence of local storage hardware are the main advantages of this type of storage. The adoption of this type of storage is being driven by its accessibility. However, one of the main barriers to its widespread adoption is the sovereignty issues originated by lack of trust in storing private and sensitive information in such a medium. Recent attacks to cloud-based storage show that current solutions do not provide adequate levels of security and subsequently fail to protect users' privacy. Usually, users rely solely on the security supplied by the storage providers, which in the presence of a security breach will ultimate lead to data leakage. In this paper, we propose and implement a broker (ARGUS) that acts as a proxy to the existing public cloud infrastructures by performing all the necessary authentication, cryptography and erasure coding. ARGUS uses erasure code as a way to provide efficient redundancy (opposite to standard replication) while adding an extra layer to data protection in which data is broken into fragments, expanded and encoded with redundant data pieces that are stored across a set of different storage providers (public or private). The key characteristics of ARGUS are confidentiality, integrity and availability of data stored in public cloud systems.

Abstract
Economical benefits obtained by large Internet corporations from gathering and processing user information at a global scale led the European Union to legislate on behalf of individual rights and the privacy of personal information. Data collectors, in particular, must now obtain proof of the user’s consent for every single operation comprising their data. Considering the conflicting interests of all involved parties, we propose that consent should be stored in a blockchain. By being a distributed, immutable and verifiable ledger, the blockchain presents itself as an almost tailor-made solution to harmonize conflicting interests while enabling the regulators’ supervision. © Springer Nature Switzerland AG 2019.

Abstract
The benefits of blockchain go beyond its applicability in finance. Electronic Voting Systems (EVS) are considered as a way to achieve a more effective act of voting. EVS are expected to be verifiable and tamper resistant. The blockchain partially fulfills this requirements of EVS by being an immutable, verifiable and distributed record of transactions. The adoption of EVS has been hampered mainly by cultural and political issues rather than technological ones. The authors believe that blockchain is the technology that, due to the overall attention it has been receiving, is capable of fostering the adoption of EVS. In the current work we compare blockchain-based EVS, identifying their strengths and shortcomings. © Springer Nature Switzerland AG 2019.

Abstract
The digital economy, online presence and the increasing number of phishing attacks, are common realities in today's operations of a significant number of companies. Some of these attacks resulted in significant financial losses and reputational damage. Companies do not address the problem before- hand. The first step should be the assessment of the exposure of the company to phishing attacks. An assessment methodology is proposed, evaluated and tested using two complete, and real, runs of the methodology.

Abstract
This paper presents a testbed implementation and evaluation of coding for secrecy schemes in a real environment through software defined radio platforms. These coding schemes rely on interleaving and scrambling with randomly generated keys to shuffle information before transmission. These keys are then encoded jointly with data and then hidden (erased) before transmission, thus only being retrievable through parity information resulting from encoded data. An advantage of the legitimate receiver (e.g. a better signal-to-noise ratio) on the reception of those keys provides the means to achieve secrecy against an adversary eavesdropper. Through this testbed implementation, we show the practical feasibility of coding for secrecy schemes in real-world environments, unveiling the usefulness of interleaving and scrambling with a hidden key to reduce the required advantage over an eavesdropper. We further describe and present solutions to a set of issues that appear when doing practical implementations of security schemes in software defined radio platforms. © 2018 IEEE.

Abstract
Sharing location data is becoming more popular as mobile devices become ubiquitous. Location-based service providers use this type of data to provide geographically contextualized services to their users. However, sharing exact locations with possibly untrustworthy entities poses a thread to privacy. Geo-indistinguishability has been recently proposed as a formal notion based on the concept of differential privacy to design location privacy-preserving mechanisms in the context of sporadic release of location data. While adaptations for the case of continuous location updates have been proposed, the study on how the frequency of updates impacts the privacy and utility level is yet to be made. In this paper we address this issue, by analyzing the effect of frequency updates on the privacy and utility levels of four mechanisms: the standard planar Laplacian mechanism suitable for sparse locations, and three variants of an adaptive mechanism that is an adaptation of the standard mechanism for continuous location updates. Results show that the frequency of updates largely impacts the correlation between points. As the frequency of updates decreases, the correlation also decreases. The adaptive mechanism is able to adjust the privacy and utility levels accordingly to the correlation between past positions and current position. However, the estimator function that is used to predict the current location has a great influence in the obtained results.