Sarp Net: A Secure, Anonymous, Reputation-Based, Peer-To-Peer Network

Since the advent of Napster, the idea of peer-to-peer (P2P) architectures being applied to file-sharing applications has become popular, spawning other P2P networks like Gnutella, Morpheus, Kazaa, and BitTorrent. This growth in P2P development has nearly eradicated the idea of the traditional client-server structure in the file-sharing model, now placing emphasizes on faster query processing, deeper levels of decentralism, and methods to protect against copyright law violation. SARP Net is a secure, anonymous, decentralized, P2P overlay network that is designed to protect the activity of its users in its own file-sharing community. It is secure in the fact that public-key encryption is used to guard eavesdroppers during messages. The protocol guarantees user anonymity by incorporating message hopping from node to node to prevent any network observer from pinpointing the origin of any file query or shared-file source. To further enhance the system\u27s security, a reputation scheme is incorporated to police nodes from malicious activity, maintain the overlay\u27s topology, and enforce rules to protect node identity

Proof-of-Concept Application - Annual Report Year 1

In this document the Cat-COVITE Application for use in the CATNETS Project is introduced and motivated. Furthermore an introduction to the catallactic middleware and Web Services Agreement (WS-Agreement) concepts is given as a basis for the future work. Requirements for the application of Cat-COVITE with in catallactic systems are analysed. Finally the integration of the Cat-COVITE application and the catallactic middleware is described. --Grid Computing

Scenarios and system dynamics of mobile peer-to-peer content distribution

Vertaisverkkoteknologian menestys kiinteissä verkoissa on johtanut vertaisverkkototeutuksiin myös mobiileissa verkoissa. Mobiilin vertaisverkkoteknologian tulevaisuuden suhteen on tosin vielä paljon epävarmuutta, koska operaattorit ja muut sidosryhmän jäsenet, jotka kärsivät laittoman tiedostonvaihdon seurauksista kiinteän verkon puolella, pelkäävät saman tapahtuvan myös mobiileissa verkoissa. Täten he saattavat yrittää estää mobiilin vertaisverkkoteknologian kehittymistä. On myös epävarmaa onko mobiilille vertaisverkkoteknologialle tarvetta loppukäyttäjän näkökulmasta, eritoten kun mobiililaitteiden suorituskyvyt ovat huomattavasti alhaisempia kuin kiinteiden. Tämä diplomityö keskittyy mobiilin vertaisverkon sisällönjakeluun. Sisällönjakelu on jaettu tiedostonvaihtoon, sisällön suoratoistoon ja kaupallisiin sisältöjärjestelmiin. Työ antaa näkemystä mobiilin vertaisverkon sisällönjakelun olennaisimpiin skenaarioihin, sidosryhmän jäseniin ja heidän kannustimiin. Mobiilin vertaisverkon sisällönjakelun epävarmuutta rajataan käyttämällä skenaarioanalyysiä ja mallinnetaan systeemidynamiikalla. Olennaisimmat skenaariot rakennetaan Schoemakerin metodilla ja niiden mallinnusta yritetään systeemidynamiikan keinoin. Tuloksena saadaan neljä eri skenaariota, jotka on kehitetty brainstorming -tilaisuuksissa ja kirjallisuuskatsauksessa löydettyjen avaintrendien ja -epävarmuustekijöiden perusteella. Skenaarioiden kvantitatiivisen mallinnuksen sijaan mallinnetaan skenaarioihin perustuvan mobiilin vertaisverkon sisällönjakelujärjestelmän dynaamista käyttäytymistä. Vaikka joitakin mobiilia vertaisverkkoteknologiaa hyödyntäviä sovelluksia on jo kehitetty ja käytössä, sekä aihetta tutkittu laajasti, vieläkin on epävarmaa mikä teknologian vaikutus tulee olemaan. Tämä diplomityö esittää mahdollisia vaikutuksia teknologialle ja antaa lähtökohdan tulevalle mobiilien vertaisverkon sisällönjakelujärjestelmien kvantitatiiviselle mallinnukselle. Systeemidynamiikka on toteuttamiskelpoinen vaihtoehto tavallisemmille mallinnustekniikoille, kuten taulukkolaskentamallinnukselle, jonka etuna on järjestelmän takaisinkytkentäsilmukkojen mallintaminen. Kun mobiili vertaisverkkoteknologia kehittyy, enemmän dataa tulee saataville ja vaihtoehtoisten systeemidynamiikkamallien rakentaminen on suositeltavaa.The success of peer-to-peer technology in the fixed networks has led to peer-to-peer implementations in the mobile networks as well. There is, however, a lot of uncertainty regarding the future of mobile peer-to-peer technology as the operators and other stakeholders that were affected negatively by illegal peer-to-peer file sharing in the fixed networks are afraid that it might happen in the mobile domain as well. Thus they might try to prevent mobile peer-to-peer technology from emerging. There is also the question whether there really is a need for peer-to-peer technology in the mobile domain from the end users' perspective, especially as the mobile device capabilities are considerably lower compared to the fixed ones. This thesis concentrates on mobile peer-to-peer content distribution. Content distribution is divided to file exchange, content streaming and commercial content systems. The thesis provides insight to the most relevant scenarios, stakeholders and their incentives related to mobile peer-to-peer content distribution. The uncertainty regarding mobile peer-to-peer content distribution will be bounded using scenario analysis and modeled using system dynamics. The most relevant scenarios regarding mobile peer-to-peer content distribution are constructed using Schoemaker's method and modeling of these scenarios is attempted with system dynamics. As a result four different scenarios are developed based on the key trends and uncertainties discovered during the literature review and brainstorming sessions. Instead of modeling the scenarios quantitatively, the dynamic behavior of a mobile peer-to-peer content distribution system based on the scenarios is modeled with system dynamics. Although there are some mobile peer-to-peer content distribution applications already developed and used, and the topic is considerably researched, it is still uncertain what the outcome of the technology will be. This thesis presents possible outcomes for the technology and provides a starting point for further quantitative modeling of mobile peer-to-peer content distribution systems. System dynamics provides a viable alternative to more common modeling techniques such as spreadsheet modeling, with a distinctive benefit of modeling the feedback loops in a system when used proficiently. As the mobile peer-to-peer technology evolves, more data becomes available and the construction of alternative system dynamics models is encouraged

Protecting Copyright in the Digital Era in China: A Critical Analysis of the Relevant Law and Practice from a Comparative Perspective

China, as the birthplace of several great inventions, is no stranger to creativity, and, indeed, innovation. That said, while the notion of copyright has for a long time been recognised as being essential to the protection of Chinese inventions, it is perhaps regrettable that the existing system of copyright protection in that country remains largely inefficacious, at least when compared to western countries, in terms of addressing the key challenges and complexities posed by the rapid developments that characterise the digital age. It is against this backdrop that this thesis has been conceptualised; the overarching aim, in this regard, being to assess the development and nature of copyright protection in China, from a comparative perspective, in an effort to unearth the challenges that arise in the digital age, and to proffer suggestions for reform in this regard. More specifically, through the adoption of the doctrinal, historical and comparative methodologies, this thesis examines the historical evolution of copyright protection in China, and argues that while there has been some progress in recent years in terms of copyright protection that commensurate with China's economic development and international obligations, a number of outstanding issues remain unresolved, especially with regard to striking the right balance between competing interests. The thesis also evaluates the role of emerging technologies, such as peer-to-peer technology, and argues that China has struggled to address many of these challenges associated therewith, notwithstanding the progressive approaches countenanced by other jurisdictions. The thesis argues that one of the main challenges that account for the existing inadequacy that characterises China's system of copyright protection is the country's very history and culture, which do not ascribe a high degree of primacy to the exclusive rights of copyright owners. History and culture, among other, mostly legal, factors, might also account for the currently high levels of uncertainty that characterise the construction of secondary liability in relation to ISPs in China. Apart from assessing the uncertainties associated with secondary liability, however, the thesis will also examine the complexities and challenges that surround the use of emerging technologies, such as technological protection measures, that aim to protect copyright in the digital era, and argues that while these challenges are real, they are not at all insurmountable. Against this backdrop, pragmatic solutions, drawing largely from other jurisdictions, are provided throughout this thesis

Application of overlay techniques to network monitoring

Measurement and monitoring are important for correct and efficient operation of a network, since these activities provide reliable information and accurate analysis for characterizing and troubleshooting a network’s performance. The focus of network measurement is to measure the volume and types of traffic on a particular network and to record the raw measurement results. The focus of network monitoring is to initiate measurement tasks, collect raw measurement results, and report aggregated outcomes. Network systems are continuously evolving: besides incremental change to accommodate new devices, more drastic changes occur to accommodate new applications, such as overlay-based content delivery networks. As a consequence, a network can experience significant increases in size and significant levels of long-range, coordinated, distributed activity; furthermore, heterogeneous network technologies, services and applications coexist and interact. Reliance upon traditional, point-to-point, ad hoc measurements to manage such networks is becoming increasingly tenuous. In particular, correlated, simultaneous 1-way measurements are needed, as is the ability to access measurement information stored throughout the network of interest. To address these new challenges, this dissertation proposes OverMon, a new paradigm for edge-to-edge network monitoring systems through the application of overlay techniques. Of particular interest, the problem of significant network overheads caused by normal overlay network techniques has been addressed by constructing overlay networks with topology awareness - the network topology information is derived from interior gateway protocol (IGP) traffic, i.e. OSPF traffic, thus eliminating all overlay maintenance network overhead. Through a prototype that uses overlays to initiate measurement tasks and to retrieve measurement results, systematic evaluation has been conducted to demonstrate the feasibility and functionality of OverMon. The measurement results show that OverMon achieves good performance in scalability, flexibility and extensibility, which are important in addressing the new challenges arising from network system evolution. This work, therefore, contributes an innovative approach of applying overly techniques to solve realistic network monitoring problems, and provides valuable first hand experience in building and evaluating such a distributed system

Autenticación de contenidos y control de acceso en redes peer-to-peer puras

Esta tesis doctoral se enmarca dentro del área de investigación de la seguridad en entornos Peer-to-Peer (P2P) totalmente descentralizados (también denominados puros.) En particular, el objetivo principal de esta tesis doctoral es definir, analizar e implementar un esquema para la distribución segura de los contenidos compartidos. En este trabajo de tesis se han realizado importantes avances e innovadoras aportaciones enfocadas a garantizar que el contenido compartido es auténtico; es decir, que no ha sido alterado, incluso tratándose de una réplica del original. Además, se propone un mecanismo de control de acceso orientado a proporcionar servicios de autorización en un entorno que no cuenta con una jerarquía de autoridades de certificación. A continuación, se resume la metodología seguida, las principales aportaciones de esta tesis y, finalmente, se muestran las conclusiones más importantes. __________________________________________The study and analysis of the state-of-the-art on security in Peer-to-Peer (P2P) networks gives us many important insights regarding the lack of practical security mechanisms in such fully decentralized and highly dynamic networks. The major problems range from the absence of content authentication mechanisms, which address and assure the authenticity and integrity of the resources shared by networking nodes, to access control proposals, which provide authorization services. In particular, the combination of both, authentication and access control, within well-known P2P file sharing systems may involve several advances in the content replication and distribution processes. The aim of this thesis is to define, develop and evaluate a secure P2P content distribution scheme for file sharing scenarios. The proposal will be based on the use of digital certificates, similar to those used in the provision of public key authenticity. To carry out this proposal in such an environment, which does not count on a hierarchy of certification authorities, we will explore the application of non-conventional techniques, such as Byzantine agreement protocols and schemes based on “proof-of-work.” We then propose a content authentication protocol for pure P2P file sharing systems. Under certain restrictions, our scheme provides guarantees that a content is authentic, i.e. it has not been altered, even if it is a replica of the original and the source has lost control over it. Moreover, we extend our initial work by showing how digital certificates can be modified to provide authorization capabilities for self-organizing peers. The entire scheme is first theoretically analyzed, and also implemented in C and Java in order to evaluate its performance. This document is presented as Ph.D. Thesis within the 2007–08 Ph.D. in Computer Science Program at Carlos III University of Madrid

Reduce Blockchain Nodes Storage Requirements by using Distributed Hash Table.

Σκοπός της παρούσας διπλωματικής εργασίας είναι η μελέτη και η ανάλυση της επαναστατικής τεχνολογίας blockchain και η πρόταση μίας νέας προσέγγισης στην υλοποίησή της. Συγκεκριμένα, εξετάζεται η ιδέα της οργάνωσης των ομότιμων του blockchain σε DHT με σκοπό την αποθηκεύση των δεδομένων του blockchain: Καθώς τα blockchain γερνάνε, το μέγεθός τους γίνεται ολοένα και μεγαλύτερο. Αυτή τη στιγμή, το Bitcoin blockchain υπερβαίνει τα 190GB. Επιπλέον, εφόσον εφαρμοστούν ορισμένες από τις ιδέες που αφορούν την αύξηση του ρυθμού των συναλλαγών, το μέγεθος του blockchain θα αυξάνεται ακόμα πιο γρήγορα. Το συνεχώς αυξανόμενο μέγεθος του blockchain είναι ένας παράγοντας που καθιστά το σύστημα περισσότερο συγκεντρωτικό, αφού πολύ λίγοι από τους κόμβους θα είναι σε θέση να διατηρήσουν ένα πλήρες αντίγραφο των δεδομένων. Εξάλλου, οι αρχειακοί κόμβοι με ανοιχτές θύρες έχουν ελάχιστα ή καθόλου κίνητρα για να σπαταλήσουν αποθηκευτικό χώρο και εύρος ζώνης, προκειμένου να διατηρήσουν όλα τα δεδομένα και να εξυπηρετήσουν έναν νέο κόμβο κατά την εκκίνησή του. Συνεπώς, είναι λογικό να θέλουμε να μετριάζεται το φορτίο τους (ειδικά αυτό που ονομάζουμε "κρύα δεδομένα", μερικά ιστορικά μπλοκ), μοιράζοντάς το σε ένα DHT. Η αξιολόγηση αυτής της πρότασης επιτυγχάνεται μέσω προσομοιώσεων του πρώτου και πιο δημοφιλούς δικτύου blockchain, του Bitcoin: Δημιουργούμε ένα απλοποιημένο DHT που θυμίζει το Chord. Ρυθμίζουμε το σύστημά μας και δημιουργούμε ένα σύστημα του οποίου τα χαρακτηριστικά είναι παρόμοια με το Bitcoin. Μετράμε διάφορες πτυχές του συστήματος μας όπως εξοικονόμηση χωρητικότητας των κόμβων συγκριτικά με την κλασική υλοποίηση, load balance, query latency, bandwidth usage. Παρουσιάζουμε τα αποτελέσματά μας, σχολιάζουμε, και καταλήγουμε σε συμπεράσματα.The purpose of this master thesis is the study and the analysis of the novel blockchain technology, as well as a proposal of a new approach on its implementation. In particular, it considers the idea of organizing the blockchain peers into a DHT in order to store the blockchain data: As blockchains get older, their size gets larger. Currently, Bitcoin blockchain is over than 190GB. In addition, as long as some of the ideas about the increase of the transaction rate put into practice, blockchain size will grow even faster. The ever-growing size of the blockchain it is a factor of making the system more centralized, since too few of the nodes will be able to keep a full replica of the data. After all, archival nodes with open ports, have little or no incentives to waste their storage and their bandwidth, in order to keep all the data and serve it to a bootstrapping node. Thus, it is reasonable to mitigate their load (especially that we call “cold data”, some historical blocks) by splitting it into a DHT. The evaluation of this proposal is achieved through simulations of the first and most popular blockchain network, the Bitcoin: We build a simplified DHT that reminds the Chord. We tune our system and we make a system whose characteristics is similar to Bitcoin. We measure several aspects of our system such as capacity savings per node compared to the amount of data that a full node stores today, load balance, query latency, bandwidth usage. We present our results, we make comments on them, and we draw a conclusion