15 research outputs found
Study of Peer-to-Peer Network Based Cybercrime Investigation: Application on Botnet Technologies
The scalable, low overhead attributes of Peer-to-Peer (P2P) Internet
protocols and networks lend themselves well to being exploited by criminals to
execute a large range of cybercrimes. The types of crimes aided by P2P
technology include copyright infringement, sharing of illicit images of
children, fraud, hacking/cracking, denial of service attacks and virus/malware
propagation through the use of a variety of worms, botnets, malware, viruses
and P2P file sharing. This project is focused on study of active P2P nodes
along with the analysis of the undocumented communication methods employed in
many of these large unstructured networks. This is achieved through the design
and implementation of an efficient P2P monitoring and crawling toolset. The
requirement for investigating P2P based systems is not limited to the more
obvious cybercrimes listed above, as many legitimate P2P based applications may
also be pertinent to a digital forensic investigation, e.g, voice over IP,
instant messaging, etc. Investigating these networks has become increasingly
difficult due to the broad range of network topologies and the ever increasing
and evolving range of P2P based applications. In this work we introduce the
Universal P2P Network Investigation Framework (UP2PNIF), a framework which
enables significantly faster and less labour intensive investigation of newly
discovered P2P networks through the exploitation of the commonalities in P2P
network functionality. In combination with a reference database of known
network characteristics, it is envisioned that any known P2P network can be
instantly investigated using the framework, which can intelligently determine
the best investigation methodology and greatly expedite the evidence gathering
process. A proof of concept tool was developed for conducting investigations on
the BitTorrent network.Comment: This is a thesis submitted in fulfilment of a PhD in Digital
Forensics and Cybercrime Investigation in the School of Computer Science,
University College Dublin in October 201
Hoverlay : a peer-to-peer system for on demand sharing of capacity across network applications
EThOS - Electronic Theses Online ServiceGBUnited Kingdo
Hoverlay : a peer-to-peer system for on demand sharing of capacity across network applications
EThOS - Electronic Theses Online ServiceGBUnited Kingdo
Understanding Churn in Decentralized Peer-to-Peer Networks
This dissertation presents a novel modeling framework for understanding the dynamics
of peer-to-peer (P2P) networks under churn (i.e., random user arrival/departure)
and designing systems more resilient against node failure. The proposed models are
applicable to general distributed systems under a variety of conditions on graph construction
and user lifetimes.
The foundation of this work is a new churn model that describes user arrival and
departure as a superposition of many periodic (renewal) processes. It not only allows
general (non-exponential) user lifetime distributions, but also captures heterogeneous
behavior of peers. We utilize this model to analyze link dynamics and the ability
of the system to stay connected under churn. Our results offers exact computation
of user-isolation and graph-partitioning probabilities for any monotone lifetime distribution,
including heavy-tailed cases found in real systems. We also propose an
age-proportional random-walk algorithm for creating links in unstructured P2P networks
that achieves zero isolation probability as system size becomes infinite. We
additionally obtain many insightful results on the transient distribution of in-degree,
edge arrival process, system size, and lifetimes of live users as simple functions of the
aggregate lifetime distribution.
The second half of this work studies churn in structured P2P networks that are
usually built upon distributed hash tables (DHTs). Users in DHTs maintain two types of neighbor sets: routing tables and successor/leaf sets. The former tables determine
link lifetimes and routing performance of the system, while the latter are built for
ensuring DHT consistency and connectivity. Our first result in this area proves that
robustness of DHTs is mainly determined by zone size of selected neighbors, which
leads us to propose a min-zone algorithm that significantly reduces link churn in
DHTs. Our second result uses the Chen-Stein method to understand concurrent
failures among strongly dependent successor sets of many DHTs and finds an optimal
stabilization strategy for keeping Chord connected under churn
Recommended from our members
An Emergent Architecture for Scaling Decentralized Communication Systems (DCS)
With recent technological advancements now accelerating the mobile and wireless Internet solution space, a ubiquitous computing Internet is well within the research and industrial community's design reach - a decentralized system design, which is not solely driven by static physical models and sound engineering principals, but more dynamically, perhaps sub-optimally at initial deployment and socially-influenced in its evolution. To complement today's Internet system, this thesis proposes a Decentralized Communication System (DCS) architecture with the following characteristics: flat physical topologies with numerous compute oriented and communication intensive nodes in the network with many of these nodes operating in multiple functional roles; self-organizing virtual structures formed through alternative mobility scenarios and capable of serving ad hoc networking formations; emergent operations and control with limited dependency on centralized control and management administration. Today, decentralized systems are not commercially scalable or viable for broad adoption in the same way we have to come to rely on the Internet or telephony systems. The premise in this thesis is that DCS can reach high levels of resilience, usefulness, scale that the industry has come to experience with traditional centralized systems by exploiting the following properties: (i.) network density and topological diversity; (ii.) self-organization and emergent attributes; (iii.) cooperative and dynamic infrastructure; and (iv.) node role diversity. This thesis delivers key contributions towards advancing the current state of the art in decentralized systems. First, we present the vision and a conceptual framework for DCS. Second, the thesis demonstrates that such a framework and concept architecture is feasible by prototyping a DCS platform that exhibits the above properties or minimally, demonstrates that these properties are feasible through prototyped network services. Third, this work expands on an alternative approach to network clustering using hierarchical virtual clusters (HVC) to facilitate self-organizing network structures. With increasing network complexity, decentralized systems can generally lead to unreliable and irregular service quality, especially given unpredictable node mobility and traffic dynamics. The HVC framework is an architectural strategy to address organizational disorder associated with traditional decentralized systems. The proposed HVC architecture along with the associated promotional methodology organizes distributed control and management services by leveraging alternative organizational models (e.g., peer-to-peer (P2P), centralized or tiered) in hierarchical and virtual fashion. Through simulation and analytical modeling, we demonstrate HVC efficiencies in DCS structural scalability and resilience by comparing static and dynamic HVC node configurations against traditional physical configurations based on P2P, centralized or tiered structures. Next, an emergent management architecture for DCS exploiting HVC for self-organization, introduces emergence as an operational approach to scaling DCS services for state management and policy control. In this thesis, emergence scales in hierarchical fashion using virtual clustering to create multiple tiers of local and global separation for aggregation, distribution and network control. Emergence is an architectural objective, which HVC introduces into the proposed self-management design for scaling and stability purposes. Since HVC expands the clustering model hierarchically and virtually, a clusterhead (CH) node, positioned as a proxy for a specific cluster or grouped DCS nodes, can also operate in a micro-capacity as a peer member of an organized cluster in a higher tier. As the HVC promotional process continues through the hierarchy, each tier of the hierarchy exhibits emergent behavior. With HVC as the self-organizing structural framework, a multi-tiered, emergent architecture enables the decentralized management strategy to improve scaling objectives that traditionally challenge decentralized systems. The HVC organizational concept and the emergence properties align with and the view of the human brain's neocortex layering structure of sensory storage, prediction and intelligence. It is the position in this thesis, that for DCS to scale and maintain broad stability, network control and management must strive towards an emergent or natural approach. While today's models for network control and management have proven to lack scalability and responsiveness based on pure centralized models, it is unlikely that singular organizational models can withstand the operational complexities associated with DCS. In this work, we integrate emergence and learning-based methods in a cooperative computing manner towards realizing DCS self-management. However, unlike many existing work in these areas which break down with increased network complexity and dynamics, the proposed HVC framework is utilized to offset these issues through effective separation, aggregation and asynchronous processing of both distributed state and policy. Using modeling techniques, we demonstrate that such architecture is feasible and can improve the operational robustness of DCS. The modeling emphasis focuses on demonstrating the operational advantages of an HVC-based organizational strategy for emergent management services (i.e., reachability, availability or performance). By integrating the two approaches, the DCS architecture forms a scalable system to address the challenges associated with traditional decentralized systems. The hypothesis is that the emergent management system architecture will improve the operational scaling properties of DCS-based applications and services. Additionally, we demonstrate structural flexibility of HVC as an underlying service infrastructure to build and deploy DCS applications and layered services. The modeling results demonstrate that an HVC-based emergent management and control system operationally outperforms traditional structural organizational models. In summary, this thesis brings together the above contributions towards delivering a scalable, decentralized system for Internet mobile computing and communications
Solving key design issues for massively multiplayer online games on peer-to-peer architectures
Massively Multiplayer Online Games (MMOGs) are increasing in both popularity and
scale on the Internet and are predominantly implemented by Client/Server architectures.
While such a classical approach to distributed system design offers many benefits, it suffers
from significant technical and commercial drawbacks, primarily reliability and scalability
costs. This realisation has sparked recent research interest in adapting MMOGs
to Peer-to-Peer (P2P) architectures.
This thesis identifies six key design issues to be addressed by P2P MMOGs, namely
interest management, event dissemination, task sharing, state persistency, cheating mitigation,
and incentive mechanisms. Design alternatives for each issue are systematically
compared, and their interrelationships discussed. How well representative P2P MMOG
architectures fulfil the design criteria is also evaluated. It is argued that although P2P
MMOG architectures are developing rapidly, their support for task sharing and incentive
mechanisms still need to be improved.
The design of a novel framework for P2P MMOGs, Mediator, is presented. It employs a
self-organising super-peer network over a P2P overlay infrastructure, and addresses the
six design issues in an integrated system. The Mediator framework is extensible, as it
supports flexible policy plug-ins and can accommodate the introduction of new superpeer
roles. Key components of this framework have been implemented and evaluated
with a simulated P2P MMOG.
As the Mediator framework relies on super-peers for computational and administrative
tasks, membership management is crucial, e.g. to allow the system to recover from
super-peer failures. A new technology for this, namely Membership-Aware Multicast
with Bushiness Optimisation (MAMBO), has been designed, implemented and evaluated.
It reuses the communication structure of a tree-based application-level multicast
to track group membership efficiently. Evaluation of a demonstration application shows
i
that MAMBO is able to quickly detect and handle peers joining and leaving. Compared
to a conventional supervision architecture, MAMBO is more scalable, and yet incurs
less communication overheads. Besides MMOGs, MAMBO is suitable for other P2P
applications, such as collaborative computing and multimedia streaming.
This thesis also presents the design, implementation and evaluation of a novel task
mapping infrastructure for heterogeneous P2P environments, Deadline-Driven Auctions
(DDA). DDA is primarily designed to support NPC host allocation in P2P MMOGs, and
specifically in the Mediator framework. However, it can also support the sharing of computational
and interactive tasks with various deadlines in general P2P applications. Experimental
and analytical results demonstrate that DDA efficiently allocates computing
resources for large numbers of real-time NPC tasks in a simulated P2P MMOG with approximately
1000 players. Furthermore, DDA supports gaming interactivity by keeping
the communication latency among NPC hosts and ordinary players low. It also supports
flexible matchmaking policies, and can motivate application participants to contribute
resources to the system
Interdisciplinarity in the Scholarly Life Cycle
This open access book illustrates how interdisciplinary research develops over the lifetime of a scholar: not in a single project, but as an attitude that trickles down, or spirals up, into research. This book presents how interdisciplinary work has inspired shifts in how the contributors read, value concepts, critically combine methods, cope with knowledge hierarchies, write in style, and collaborate. Drawing on extensive examples from the humanities and social sciences, the editors and chapter authors show how they started, tried to open up, dealt with inconsistencies, had to adapt, and ultimately learned and grew as researchers. The book offers valuable insights into the conditions and complexities present for interdisciplinary research to be successful in an academic setting. This is an open access book
Interdisciplinarity in the Scholarly Life Cycle
This open access book illustrates how interdisciplinary research develops over the lifetime of a scholar: not in a single project, but as an attitude that trickles down, or spirals up, into research. This book presents how interdisciplinary work has inspired shifts in how the contributors read, value concepts, critically combine methods, cope with knowledge hierarchies, write in style, and collaborate. Drawing on extensive examples from the humanities and social sciences, the editors and chapter authors show how they started, tried to open up, dealt with inconsistencies, had to adapt, and ultimately learned and grew as researchers. The book offers valuable insights into the conditions and complexities present for interdisciplinary research to be successful in an academic setting. This is an open access book