Contour: A Practical System for Binary Transparency

Transparency is crucial in security-critical applications that rely on authoritative information, as it provides a robust mechanism for holding these authorities accountable for their actions. A number of solutions have emerged in recent years that provide transparency in the setting of certificate issuance, and Bitcoin provides an example of how to enforce transparency in a financial setting. In this work we shift to a new setting, the distribution of software package binaries, and present a system for so-called "binary transparency." Our solution, Contour, uses proactive methods for providing transparency, privacy, and availability, even in the face of persistent man-in-the-middle attacks. We also demonstrate, via benchmarks and a test deployment for the Debian software repository, that Contour is the only system for binary transparency that satisfies the efficiency and coordination requirements that would make it possible to deploy today.Comment: International Workshop on Cryptocurrencies and Blockchain Technology (CBT), 201

Securely Scaling Blockchain Base Layers

This thesis presents the design, implementation and evaluation of techniques to scale the base layers of decentralised blockchain networks---where transactions are directly posted on the chain. The key challenge is to scale the base layer without sacrificing properties such as decentralisation, security and public verifiability. It proposes Chainspace, a blockchain sharding system where nodes process and reach consensus on transactions in parallel, thereby scaling block production and increasing on-chain throughput. In order to make the actions of consensus-participating nodes efficiently verifiable despite the increase of on-chain data, a system of fraud and data availability proofs is proposed so that invalid blocks can be efficiently challenged and rejected without the need for all users to download all transactions, thereby scaling block verification. It then explores blockchain and application design paradigms that enable on-chain scalability on the outset. This is in contrast to sharding, which scales blockchains designed under the traditional state machine replication paradigm where consensus and transaction execution are coupled. LazyLedger, a blockchain design where the consensus layer separated from the execution layer is proposed, where the consensus is only responsible for checking the availability of the data in blocks via data availability proofs. Transactions are instead executed off-chain, eliminating the need for nodes to execute on-chain transactions in order to verify blocks. Finally, as an example of a blockchain use case that does not require an execution layer, Contour, a scalable design for software binary transparency is proposed on top of the existing Bitcoin blockchain, where all software binary records do not need to be posted on-chain

Workers Attitudes in the Municipalities and Provinces towards the Decentralized and Regional Project in Jordan

The present study aimed to identify the attitudes of workers in local Jordanian public departments as a project towards decentralization of territories of its municipalities in Jordan, The study sample consist of (228) managers, and employees of different ranks whom are working in municipalities and local governmental departments, in order to answer the study questions and hypotheses, the researcher developed questionnaires to measure main variables of the study. Some statistical techniques were used for testing the hypotheses and answering the study questions. The present study revealed the following findings: There is statistically significant correlation between decentralization advantages and environmental factors.There are no statistically significant impact of investigators attitudes toward advantages and disadvantages of decentralization according to demographic factors.There is statistically significant impact of scientific qualification attitudes toward decentralization disadvantages.There is statistically significant impact of investigators attitudes toward decentralization disadvantages and advantages. Keywords: decentralization, attitudes, territories, project in Jordan, environmental factors Participation, political factors, social factors, financial, Developmental planning Factors, organizational factors

Chainspace: A Sharded Smart Contracts Platform

Chainspace is a decentralized infrastructure, known as a distributed ledger, that supports user defined smart contracts and executes user-supplied transactions on their objects. The correct execution of smart contract transactions is verifiable by all. The system is scalable, by sharding state and the execution of transactions, and using S-BAC, a distributed commit protocol, to guarantee consistency. Chainspace is secure against subsets of nodes trying to compromise its integrity or availability properties through Byzantine Fault Tolerance (BFT), and extremely high-auditability, non-repudiation and `blockchain' techniques. Even when BFT fails, auditing mechanisms are in place to trace malicious participants. We present the design, rationale, and details of Chainspace; we argue through evaluating an implementation of the system about its scaling and other features; we illustrate a number of privacy-friendly smart contracts for smart metering, polling and banking and measure their performance

Proof-of-Prestige: A Useful Work Reward System for Unverifiable Tasks

As cryptographic tokens and altcoins are increasingly being built to serve as utility tokens, the notion of useful work consensus protocols, as opposed to number-crunching PoW consensus, is becoming ever more important. In such contexts, users get rewards from the network after they have carried out some specific task useful for the network. While in some cases the proof of some utility or service can be proved, the majority of tasks are impossible to verify. In order to deal with such cases, we design Proof-of-Prestige (PoP) - a reward system that can run on top of Proof-of-Stake blockchains. PoP introduces prestige which is a volatile resource and, in contrast to coins, regenerates over time. Prestige can be gained by performing useful work, spent when benefiting from services and directly translates to users minting power. PoP is resistant against Sybil and Collude attacks and can be used to reward workers for completing unverifiable tasks, while keeping the system free for the end-users. We use two exemplar use-cases to showcase the usefulness of PoP and we build a simulator to assess the cryptoeconomic behaviour of the system in terms of prestige transfer between nodes.Comment: 2019 IEEE International Conference on Blockchain and Cryptocurrency (ICBC 2019

Impact of Transformational Leadership of University Presidents on Intrinsic Job Satisfaction for Academic Deans and Department Chairs at Jordan Universities

This study aims to clarify the impact of transformational leadership among university presidents on intrinsic job satisfaction for academic deans and department chairs in both the official and private Jordanian universities. The study population consists of (1052) academic deans and department chairs, while the number of the sample reached (449) academic deans and department chairs. The study's sample was chosen randomly by stratified random sampling, from which (413) questionnaires were retrieved to identify validity for statistical analysis. The results of the study found a medium level of existence of transformational leadership and a high level of existence intrinsic job satisfaction. The study found that there is an average level for the exercise of transformational leadership by university presidents and high level of availability of job satisfaction for deans and heads of academic departments, and the results showed multiple regression progressive analysis that more dimensions ability to predict the level of job satisfaction is the perfect effect and interpreted (21.9%) of the variance in Job satisfaction, then the idealized influence and individual consideration together, which accounted for a proportion (22.7%) of the variance in job satisfaction . The results of stepwise multiple regression also showed that the best predictor of intrinsic  job satisfaction is idealized influence which explained (34.3%) of the variation followed by idealized influence and individual consideration which together explained (36.8%) of the variation in intrinsic  job satisfaction.Based on the results above the researchers presented a number of recommendations , which included the establishment of institutes to train and prepare leaders to practice transformational leadership, University presidents placed greater importance on the factors that constitute academic deans and department chairs satisfaction and the improvement of salary levels. Key words: Transformational Leadership, Intrinsic Job Satisfaction, Official Universities, Private Universities, Faculty Deans, Department Chairs