Behavioural verification: preventing report fraud in decentralized advert distribution systems

Service commissions, which are claimed by Ad-Networks and Publishers, are susceptible to forgery as non-human operators are able to artificially create fictitious traffic on digital platforms for the purpose of committing financial fraud. This places a significant strain on Advertisers who have no effective means of differentiating fabricated Ad-Reports from those which correspond to real consumer activity. To address this problem, we contribute an advert reporting system which utilizes opportunistic networking and a blockchain-inspired construction in order to identify authentic Ad-Reports by determining whether they were composed by honest or dishonest users. What constitutes a user's honesty for our system is the manner in which they access adverts on their mobile device. Dishonest users submit multiple reports over a short period of time while honest users behave as consumers who view adverts at a balanced pace while engaging in typical social activities such as purchasing goods online, moving through space and interacting with other users. We argue that it is hard for dishonest users to fake honest behaviour and we exploit the behavioural patterns of users in order to classify Ad-Reports as real or fabricated. By determining the honesty of the user who submitted a particular report, our system offers a more secure reward-claiming model which protects against fraud while still preserving the user's anonymity

Joint optimisation of privacy and cost of in-app mobile user profiling and targeted ads

Online mobile advertising ecosystems provide advertising and analytics services that collect, aggregate, process and trade rich amount of consumer's personal data and carries out interests-based ads targeting, which raised serious privacy risks and growing trends of users feeling uncomfortable while using internet services. In this paper, we address user's privacy concerns by developing an optimal dynamic optimisation cost-effective framework for preserving user privacy for profiling, ads-based inferencing, temporal apps usage behavioral patterns and interest-based ads targeting. A major challenge in solving this dynamic model is the lack of knowledge of time-varying updates during profiling process. We formulate a mixed-integer optimisation problem and develop an equivalent problem to show that proposed algorithm does not require knowledge of time-varying updates in user behavior. Following, we develop an online control algorithm to solve equivalent problem using Lyapunov optimisation and to overcome difficulty of solving nonlinear programming by decomposing it into various cases and achieve trade-off between user privacy, cost and targeted ads. We carry out extensive experimentations and demonstrate proposed framework's applicability by implementing its critical components using POC `System App'. We compare proposed framework with other privacy protecting approaches and investigate that it achieves better privacy and functionality for various performance parameters

Security and Privacy Preservation in Mobile Advertising

Mobile advertising is emerging as a promising advertising strategy, which leverages prescriptive analytics, location-based distribution, and feedback-driven marketing to engage consumers with timely and targeted advertisements. In the current mobile advertising system, a third-party ad broker collects and manages advertisements for merchants who would like to promote their business to mobile users. Based on its large-scale database of user profiles, the ad broker can help the merchants to better reach out to customers with related interests and charges the merchants for ad dissemination services. Recently, mobile advertising technology has dominated the digital advertising industry and has become the main source of income for IT giants. However, there are many security and privacy challenges that may hinder the continuous success of the mobile advertising industry. First, there is a lack of advertising transparency in the current mobile advertising system. For example, mobile users are concerned about the reliability and trustworthiness of the ad dissemination process and advertising review system. Without proper countermeasures, mobile users can install ad-blocking software to filter out irrelevant or even misleading advertisements, which may lower the advertising investments from merchants. Second, as more strict privacy regulations (e.g. European General Data Privacy Regulations) take effect, it is critical to protect mobile users’ personal profiles from illegal sharing and exposure in the mobile advertising system. In this thesis, three security and privacy challenges for the mobile advertising system are identified and addressed with the designs, implementations, and evaluations of a blockchain-based architecture. First, we study the anonymous review system for the mobile advertising industry. When receiving advertisements from a specific merchant (e.g. a nearby restaurant), mobile users are more likely to browse the previous reviews about the merchant for quality-of-service assessments. However, current review systems are known for the lack of system transparency and are subject to many attacks, such as double reviews and deletions of negative reviews. We exploit the tamper-proof nature and the distributed consensus mechanism of the blockchain technology, to design a blockchain-based review system for mobile advertising, where review accumulations are transparent and verifiable to the public. To preserve user review privacy, we further design an anonymous review token generation scheme, where users are encouraged to leave reviews anonymously while still ensuring the review authenticity. We also explore the implementation challenges of the blockchain-based system on an Ethereum testing network and the experimental results demonstrate the application feasibility of the proposed anonymous review system. Second, we investigate the transparency issues for the targeted ad dissemination process. Specifically, we focus on a specific mobile advertising application: vehicular local advertising, where vehicular users send spatial-keyword queries to ad brokers to receive location-aware advertisements. To build a transparent advertising system, the ad brokers are required to provide mobile users with explanations on the ad dissemination process, e.g., why a specific ad is disseminated to a mobile user. However, such transparency explanations are often found incomplete and sometimes even misleading, which may lower the user trust on the advertising system if without proper countermeasures. Therefore, we design an advertising smart contract to efficiently realize a publicly verifiable spatial-keyword query scheme. Instead of directly implementing the spatial-keyword query scheme on the smart contract with prohibitive storage and computation cost, we exploit the on/off-chain computation models to trade the expensive on-chain cost for cheap off-chain cost. With two design strategies: digest-and-verify and divide-then-assemble, the on-chain cost for a single spatial keyword query is reduced to constant regardless of the scale of the spatial-keyword database. Extensive experiments are conducted to provide both on-chain and off-chain benchmarks with a verifiable computation framework. Third, we explore another critical requirement of the mobile advertising system: public accountability enforcement against advertising misconducts, if (1) mobile users receive irrelevant ads, or (2) advertising policies of merchants are not correctly computed in the ad dissemination process. This requires the design of a composite Succinct Non-interactive ARGument (SNARG) system, that can be tailored for different advertising transparency requirements and is efficient for the blockchain implementations. Moreover, pursuing public accountability should also achieve a strict privacy guarantee for the user profile. We also propose an accountability contract which can receive explanation requirements from both mobile users and merchants. To promote prompt on-chain responses, we design an incentive mechanism based on the pre-deposits of involved parties, i.e., ad brokers, mobile users, and merchants. If any advertising misconduct is identified, public accountability can be enforced by confiscating the pre-deposits of the misbehaving party. Comprehensive experiments and analyses are conducted to demonstrate the versatile functionalities and feasibility of the accountability contract. In summary, we have designed, implemented, and evaluated a blockchain-based architecture for security and privacy preservations in the mobile advertising. The designed architecture can not only enhance the transparency and accountability for the mobile advertising system, but has also achieved notably on-chain efficiency and privacy for real-world implementations. The results from the thesis may shed light on the future research and practice of a blockchain-based architecture for the privacy regulation compliance in the mobile advertising

Decrypting the Trends of International Regulatory Competition in Cryptoassets

The icos market has challenged financial regulators in terms of determining fit with existing regimes and consideration for regulatory reform. Regulatory divergences have emerged in a number of jurisdictions and we discuss three dominant approaches in relation to hegemonic, self-regulatory and enabling regimes. These reflect different assumptions and regulators’ understandings of the cryptoasset industry, and we argue that the ‘terms for competition’ in relation to supply and demand side needs are still being discovered and are incomplete. This provides a unique opportunity for regulators to jettison familiar assumptions in relation to corporatized securities issuers or institutional investors in order to discover what governance needs are truly at stake. This may pose challenges for coherence with existing regulation but coherence should not itself be an obstacle for learning and potentially, reform. We also argue that signs of international regulatory coordination in relation to the Libra project are not necessarily reflective of a wider trend for the cryptoasset industry. This is because regulators can apply existing and familiar financial regulation paradigms more easily to the Libra Association, in particular its leading founding member Facebook. The cryptoasset market is still likely to give rise to diversity and should facilitate the discovery of new bases for regulatory thinking and policy, uncoordinated or otherwise

Decentralised computer systems

The architecture of the Web was designed to enable decentralised exchange of information. Early architects envisioned an egalitarian yet organic society thriving in cyberspace. The reality of the Web today, unfortunately, does not bear out these visions: information networks have repeatedly shown a tendency towards consolidation and centralisation with the current Web split between a handful of large corporations. The advent of Bitcoin and successor blockchain networks re-ignited interest in developing alternatives to the centralised Web and paving a way back to the earlier architectural visions for the Web. This has led to immense hype around these technologies with the cryptocurrency market valued at several hundred billions of dollars at the time of writing. With great hype, apparently, come great scams. I start off by analysing the use of Bitcoin as an enabler for crime and then present both technical solutions as well as policy recommendations to mitigate the harm these crimes cause. These policy recommendations then lead us on to look more closely at cryptocurrency's tamer cousin: permissioned blockchains. These systems, while less revolutionary in their premise, nevertheless aim to provide sweeping improvements in the efficiency and transparency of existing enterprise systems. To see whether they work in practice, I present the results of my work in delivering a production permissioned blockchain system to real users. This involves comparing several permissioned blockchain systems, exploring their deficiencies and developing solutions for the most egregious of those. Lastly, I do a deep dive into one of the most persistent technical issues with permissioned blockchains, and decentralised networks in general: the lack of scalability in their consensus mechanisms. I present two novel consensus algorithms that aim to improve upon the state of the art in several ways. The first is designed to enable existing permissioned blockchain networks to scale to thousands of nodes. The second presents an entirely new way of building decentralised consensus systems utilising a trie-based data structure at its core as opposed to the usual linear ledgers used in current systems

Financing the Future of Asia: Innovations in Sustainable Finance

Around the globe, a wave of financial innovation that seeks to create social and environmental benefits while producing attractive returns is shaping the field of sustainable finance.From investments in publicly listed corporations based on environmental, social, and governance factors, to bonds issued to fund climate and environmental improvements; from micro-credit to small retailers through innovative credit assessments, to parametric insurance products improving the disaster resilience of countries, the world of sustainable finance is growing and becoming increasingly diverse.In this report, we take a closer look at these innovations and more, highlighting how they are working to mobilize private-sector capital at scale to address social and environmental challenges. We also explore recent developments and potential opportunities in Asia's four largest economies: China, India, Japan, and Indonesia