6 research outputs found
CRM: a new dynamic cross-layer reputation computation model in wireless networks
This is the author accepted manuscript. The final version is available from University Press (OUP) via the DOI in this record.Multi-hop wireless networks (MWNs) have been widely accepted as an indispensable
component of next-generation communication systems due to their broad applications and easy
deployment without relying on any infrastructure. Although showing huge benefits, MWNs face many
security problems, especially the internal multi-layer security threats being one of the most challenging
issues. Since most security mechanisms require the cooperation of nodes, characterizing and learning
actions of neighboring nodes and the evolution of these actions over time is vital to construct an
efficient and robust solution for security-sensitive applications such as social networking, mobile
banking, and teleconferencing. In this paper, we propose a new dynamic cross-layer reputation
computation model named CRM to dynamically characterize and quantify actions of nodes. CRM
couples uncertainty based conventional layered reputation computation model with cross-layer design
and multi-level security technology to identify malicious nodes and preserve security against internal
multi-layer threats. Simulation results and performance analyses demonstrate that CRM can provide
rapid and accurate malicious node identification and management, and implement the security
preservation against the internal multi-layer and bad mouthing attacks more effectively and efficiently
than existing models.The authors would like to thank anonymous reviewers and editors for their constructive comments.
This work is supported by: 1. Changjiang Scholars and Innovative Research Team in University
(IRT1078), 2. the Key Program of NSFC-Guangdong Union Foundation (U1135002), 3. National
Natural Science Foundation of China (61202390), 4. Fujian Natural Science Foundation:2013J01222,
5. the open research fund of Key Lab of Broadband Wireless Communication and Sensor Network
Technology (Nanjing University of Posts and Telecommunications, Ministry of Education)
Toward better data veracity in mobile cloud computing: A context-aware and incentive-based reputation mechanism
This is the author accepted manuscript. The final version is available from the publisher via the DOI in this record.As a promising next-generation computing paradigm, Mobile Cloud Computing (MCC) enables the large-scale collection and big data processing of personal private data. An important but often overlooked V of big data is data veracity, which ensures that the data used are trusted, authentic, accurate and protected from unauthorized access and modification. In order to realize the veracity of data in MCC, specific trust models and approaches must be developed. In this paper, a Category-based Context-aware and Recommendation incentive-based reputation Mechanism (CCRM) is proposed to defend against internal attacks and enhance data veracity in MCC. In the CCRM, innovative methods, including a data category and context sensing technology, a security relevance evaluation model, and a Vickrey-Clark-Groves (VCG)-based recommendation incentive scheme, are integrated into the process of reputation evaluation. Cost analysis indicates that the CCRM has a linear communication and computation complexity. Simulation results demonstrate the superior performance of the CCRM compared to existing reputation mechanisms under internal collusion attacks and bad mouthing attacks.This work is supported by the National Natural Science Foundation of China (61363068, 61472083, 61671360), the Pilot Project of Fujian Province (formal industry key project) (2016Y0031), the Foundation of Science and Technology on Information Assurance Laboratory (KJ-14-109) and the Fujian Provincial Key Laboratory of Network Security and Cryptology Research Fund
Guru: Universal Reputation Module for Distributed Consensus Protocols
In this paper we describe how to couple reputation systems with distributed consensus protocols to provide high-throughput highly-scalable consensus for large peer-to-peer networks of untrusted validators.
We introduce reputation module Guru, which can be laid on top of various consensus protocols such as PBFT or HoneyBadger. It ranks nodes based on the outcomes of consensus rounds run by a small committee, and adaptively selects the committee based on the current reputation. The protocol can also take external reputation ranking as input. Guru can tolerate larger threshold of malicious nodes (up to slightly above 1/2) compared to the 1/3 limit of BFT consensus algorithms
Classification and Comparative Study of Routing Techniques in Adhoc Wireless Networks
Wireless systems have been in use since 1980s. We have seen their evolutions to first, second and third generation's wireless systems. Wireless systems operate with the aid of a centralized supporting structure such as an access point. These access points assist the wireless users to keep connected with the wireless system, when they roam from one place to the other.
The presence of a fixed supporting structure limits the adaptability of wireless systems. In other words, the technology cannot work effectively in places where there is no fixed infrastructure. Future generation wireless systems will require easy and quick deployment of wireless networks. This quick network deployment is not possible with the Infrastructured wireless systems.
Recent advancements such as Bluetooth introduced a new type of wireless systems known as ad-hoc networks. Ad-hoc networks or "short live" networks operate in the absence of fixed infrastructure. They offer quick and easy network deployment in situations where it is not possible otherwise. Ad-hoc is a Latin word, which means "for this or for this only." Mobile ad-hoc network is an autonomous system of mobile nodes connected by wireless links; each node operates as an end system and a router for all other nodes in the network.
Nodes in ad-hoc network are free to move and organize themselves in an arbitrary fashion. Each user is free to roam about while communication with others. The path between each pair of the users may have multiple links and the radio between them can be heterogeneous. This allows an association of various links to be a part of the same network.
A mobile ad-hoc network is a collection of mobile nodes forming an ad-hoc network without the assistance of any centralized structures. These networks introduced a new art of network establishment and can be well suited for an environment where either the infrastructure is lost or where deploy an infrastructure is not very cost effective. The popular IEEE 802.11 "WI-FI" protocol is capable of providing ad-hoc network facilities at low level, when no access point is available. However in this case, the nodes are limited to send and receive information but do not route anything across the network. Ad-hoc networks can operate in a standalone fashion or could possibly be connected to a larger network such as the Internet.
An ad-hoc network has certain characteristics, which imposes new demands on the routing protocol. The most important characteristic is the dynamic topology, which is a consequence of node mobility. Nodes can change position quite frequently; the nodes in an ad-hoc network can consist of laptops and personal digital assistants and are often very limited in resources such as CPU power, storage capacity, battery power and bandwidth. This means that the routing protocol should try to minimize control traffic, such as periodic update messages. The Internet Engineering Task Force currently has a working group named Mobile Ad-hoc Networks that is working on routing specifications for ad-hoc networks. This M.Phill thesis evaluates some of the protocols put forth by the working group. This evaluation is done by means of simulation using Network simulator 2 from Berkeley.
This work aims at classification of the existing routing protocols of adhoc wireless networks using some definite parameters. After classification of routing protocols of adhoc wireless network, their comparative study was undertaken in order to yield category wise distribution. Furthermore performance evaluation of these protocols was carried out by employing different parameters like fading models, mobility models, traffic patterns etc using the network simulator NS-2
Hence I explore and evaluate different methods for validation of ad hoc routing protocols which are used to set up forwarding paths in spontaneous networks of mobile/Adhoc devices to accomplish the above mentioned comparative study and classification
Enhancing trustability in MMOGs environments
Massively Multiplayer Online Games (MMOGs; e.g., World of Warcraft), virtual worlds
(VW; e.g., Second Life), social networks (e.g., Facebook) strongly demand for more
autonomic, security, and trust mechanisms in a way similar to humans do in the real
life world. As known, this is a difficult matter because trusting in humans and organizations
depends on the perception and experience of each individual, which is difficult to
quantify or measure. In fact, these societal environments lack trust mechanisms similar
to those involved in humans-to-human interactions. Besides, interactions mediated
by compute devices are constantly evolving, requiring trust mechanisms that keep the
pace with the developments and assess risk situations.
In VW/MMOGs, it is widely recognized that users develop trust relationships from their
in-world interactions with others. However, these trust relationships end up not being
represented in the data structures (or databases) of such virtual worlds, though they
sometimes appear associated to reputation and recommendation systems. In addition,
as far as we know, the user is not provided with a personal trust tool to sustain his/her
decision making while he/she interacts with other users in the virtual or game world.
In order to solve this problem, as well as those mentioned above, we propose herein a
formal representation of these personal trust relationships, which are based on avataravatar
interactions. The leading idea is to provide each avatar-impersonated player
with a personal trust tool that follows a distributed trust model, i.e., the trust data is
distributed over the societal network of a given VW/MMOG.
Representing, manipulating, and inferring trust from the user/player point of view certainly
is a grand challenge. When someone meets an unknown individual, the question
is “Can I trust him/her or not?”. It is clear that this requires the user to have access to
a representation of trust about others, but, unless we are using an open source VW/MMOG,
it is difficult —not to say unfeasible— to get access to such data. Even, in an open
source system, a number of users may refuse to pass information about its friends, acquaintances,
or others. Putting together its own data and gathered data obtained from
others, the avatar-impersonated player should be able to come across a trust result
about its current trustee. For the trust assessment method used in this thesis, we use
subjective logic operators and graph search algorithms to undertake such trust inference
about the trustee. The proposed trust inference system has been validated using
a number of OpenSimulator (opensimulator.org) scenarios, which showed an accuracy
increase in evaluating trustability of avatars.
Summing up, our proposal aims thus to introduce a trust theory for virtual worlds, its
trust assessment metrics (e.g., subjective logic) and trust discovery methods (e.g.,
graph search methods), on an individual basis, rather than based on usual centralized
reputation systems. In particular, and unlike other trust discovery methods, our methods
run at interactive rates.MMOGs (Massively Multiplayer Online Games, como por exemplo, World of Warcraft),
mundos virtuais (VW, como por exemplo, o Second Life) e redes sociais (como por exemplo,
Facebook) necessitam de mecanismos de confiança mais autónomos, capazes de
assegurar a segurança e a confiança de uma forma semelhante à que os seres humanos
utilizam na vida real. Como se sabe, esta não é uma questão fácil. Porque confiar em
seres humanos e ou organizações depende da percepção e da experiência de cada indivíduo,
o que é difícil de quantificar ou medir à partida. Na verdade, esses ambientes
sociais carecem dos mecanismos de confiança presentes em interacções humanas presenciais.
Além disso, as interacções mediadas por dispositivos computacionais estão em
constante evolução, necessitando de mecanismos de confiança adequados ao ritmo da
evolução para avaliar situações de risco.
Em VW/MMOGs, é amplamente reconhecido que os utilizadores desenvolvem relações
de confiança a partir das suas interacções no mundo com outros. No entanto, essas relações
de confiança acabam por não ser representadas nas estruturas de dados (ou bases
de dados) do VW/MMOG específico, embora às vezes apareçam associados à reputação
e a sistemas de reputação. Além disso, tanto quanto sabemos, ao utilizador não lhe
é facultado nenhum mecanismo que suporte uma ferramenta de confiança individual
para sustentar o seu processo de tomada de decisão, enquanto ele interage com outros
utilizadores no mundo virtual ou jogo. A fim de resolver este problema, bem como
os mencionados acima, propomos nesta tese uma representação formal para essas relações
de confiança pessoal, baseada em interacções avatar-avatar. A ideia principal
é fornecer a cada jogador representado por um avatar uma ferramenta de confiança
pessoal que segue um modelo de confiança distribuída, ou seja, os dados de confiança
são distribuídos através da rede social de um determinado VW/MMOG.
Representar, manipular e inferir a confiança do ponto de utilizador/jogador, é certamente
um grande desafio. Quando alguém encontra um indivíduo desconhecido, a
pergunta é “Posso confiar ou não nele?”. É claro que isto requer que o utilizador tenha
acesso a uma representação de confiança sobre os outros, mas, a menos que possamos
usar uma plataforma VW/MMOG de código aberto, é difícil — para não dizer impossível
— obter acesso aos dados gerados pelos utilizadores. Mesmo em sistemas de código
aberto, um número de utilizadores pode recusar partilhar informações sobre seus amigos,
conhecidos, ou sobre outros. Ao juntar seus próprios dados com os dados obtidos de
outros, o utilizador/jogador representado por um avatar deve ser capaz de produzir uma
avaliação de confiança sobre o utilizador/jogador com o qual se encontra a interagir.
Relativamente ao método de avaliação de confiança empregue nesta tese, utilizamos
lógica subjectiva para a representação da confiança, e também operadores lógicos da
lógica subjectiva juntamente com algoritmos de procura em grafos para empreender
o processo de inferência da confiança relativamente a outro utilizador. O sistema de
inferência de confiança proposto foi validado através de um número de cenários Open-Simulator (opensimulator.org), que mostrou um aumento na precisão na avaliação da
confiança de avatares.
Resumindo, a nossa proposta visa, assim, introduzir uma teoria de confiança para mundos
virtuais, conjuntamente com métricas de avaliação de confiança (por exemplo, a
lógica subjectiva) e em métodos de procura de caminhos de confiança (com por exemplo,
através de métodos de pesquisa em grafos), partindo de uma base individual, em
vez de se basear em sistemas habituais de reputação centralizados. Em particular, e ao
contrário de outros métodos de determinação do grau de confiança, os nossos métodos
são executados em tempo real