309,136 research outputs found
MULTIMEDIA ON GEOGRAPHIC NETWORK
In this thesis we investigate the topic of the multimedia contents distribution on a geo-
graphic network which is a rarefied and huge field. First of all we have to classify the main
parts necessary in the multimedia distribution on a geographic network. The main aspects
of a geographic network that will be highlighted in this thesis are: the mechanism used to
retrieve the sources of the multimedia content; in the case of the peer-to-peer network on
geographic network one of the most important mechanism is the query flooding protocol.
The kind of overlay network (peer-to-peer) used to distribute the multimedia content. The
usage of this overlay network in a multicast network. The security of the overlay network
over a geographic network.
Therefore the first topic which is investigated in this thesis is the query flooding protocol
that can be used in any kind of query operation on a peer-to-peer network. For this protocol
we achieve an analytical model through a complex analysis of the proxies network. In this
analysis we can see how the proxies permit an improvement in the performance with respect
to the routing operations in a generic network of routers. Moreover we address a simple
formulation and framework about the performance of the network with and without layer
7 (proxy) and we apply them in three different types of scenarios to show the advantages
achieved with the usage of proxies instead of routers.
Through the query flooding operation, each peer of the peer-to-peer network can achieve
the list of the peers that hold the desired multimedia content. In a multimedia content dis-
tribution system, after the previous step in which the list of the peers that hold the desired multimedia content is retrieved, it is necessary to establish the kind of peer-to-peer network
used to distribute this multimedia content to the peers that require it. Therefore the second
aspect analysed in this thesis, is how the peer-to-peer network is built so that it is possible to
provide the multimedia content to the vast majority of peers (that require this content) with
the minimum delay. The construction of the peer-to-peer networks used for the distribution
of the multimedia contents is not a very investigated field. Thus in this thesis we produce
new algorithms used to build peer-to-peer networks in an incremental way on asymmetric
and radio channel and we establish which algorithm is better with respect to the maximum
delay of the network, the maximization of the number of peers accepted in the network and
the minimization of the bit error probability of each peer of the peer-to-peer network.
In this thesis, we propose an usage of the overlay network (peer-to-peer network) in
a multicast network. We introduce an innovative mechanism that exploits the peer-to-peer
network to make reliable a standard unreliable multicast network. Moreover we present an
analytical model for this innovative mechanism.
Finally the last aspect of a geographic network is the security of the communications
among a group of peers. Thus to ensure the maximum level of security with secure commu-
nications among a group of three or more peers, in this thesis we propose a new protocol,
based on the Massey Omura protocol, which can allow the communications among the
peers of a peer-to-peer network in a secure way. Moreover we present the security prob-
lems of this Massey Omura Multiple Users Protocol and how it is possible to avoid these
issues through a specific encryption function and a specific decryption function by chang-
ing the encryption and decryption keys of each peer when the source peer changes. Finally
we present a new cryptography protocol which we use to share the decryption shared key
that is used in the Massey Omura Multiple Users Protocol
PeerHunter: Detecting Peer-to-Peer Botnets through Community Behavior Analysis
Peer-to-peer (P2P) botnets have become one of the major threats in network
security for serving as the infrastructure that responsible for various of
cyber-crimes. Though a few existing work claimed to detect traditional botnets
effectively, the problem of detecting P2P botnets involves more challenges. In
this paper, we present PeerHunter, a community behavior analysis based method,
which is capable of detecting botnets that communicate via a P2P structure.
PeerHunter starts from a P2P hosts detection component. Then, it uses mutual
contacts as the main feature to cluster bots into communities. Finally, it uses
community behavior analysis to detect potential botnet communities and further
identify bot candidates. Through extensive experiments with real and simulated
network traces, PeerHunter can achieve very high detection rate and low false
positives.Comment: 8 pages, 2 figures, 11 tables, 2017 IEEE Conference on Dependable and
Secure Computin
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A two‐step authentication framework for Mobile ad hoc networks
The lack of fixed infrastructure in ad hoc networks causes nodes to rely more heavily on peer nodes for communication. Nevertheless, establishing trust in such a distributed environment is very difficult, since it is not straightforward for a node to determine if its peer nodes can be trusted. An additional concern in such an environment is with whether a peer node is merely relaying a message or if it is the originator of the message. In this paper, we propose an authentication approach for protecting nodes in mobile ad hoc networks. The security requirements for protecting data link and network layers are identified and the design criteria for creating secure ad hoc networks using several authentication protocols are analyzed. Protocols based on zero knowledge and challenge response techniques are presented and their performance is evaluated through analysis and simulation
Storytelling Security: User-Intention Based Traffic Sanitization
Malicious software (malware) with decentralized communication infrastructure, such as peer-to-peer botnets, is difficult to detect. In this paper, we describe a traffic-sanitization method for identifying malware-triggered outbound connections from a personal computer. Our solution correlates user activities with the content of outbound traffic. Our key observation is that user-initiated outbound traffic typically has corresponding human inputs, i.e., keystroke or mouse clicks. Our analysis on the causal relations between user inputs and packet payload enables the efficient enforcement of the inter-packet dependency at the application level.
We formalize our approach within the framework of protocol-state machine. We define new application-level traffic-sanitization policies that enforce the inter-packet dependencies. The dependency is derived from the transitions among protocol states that involve both user actions and network events. We refer to our methodology as storytelling security.
We demonstrate a concrete realization of our methodology in the context of peer-to-peer file-sharing application, describe its use in blocking traffic of P2P bots on a host. We implement and evaluate our prototype in Windows operating system in both online and offline deployment settings. Our experimental evaluation along with case studies of real-world P2P applications demonstrates the feasibility of verifying the inter-packet dependencies. Our deep packet inspection incurs overhead on the outbound network flow. Our solution can also be used as an offline collect-and-analyze tool
Design and validation of a methodology for distributed relay service for NAT traversal in a peer-to-peer VoIP network
Voice-over-IP (VoIP) practices are widely diffused. The traditional and mostly deployed architecture is based on the IETF SIP protocol: User Agents connect to centralized servers (usually called SIP Proxies), which provide, among other features, user location service and call routing. On another side, the peer-to-peer paradigm has proven to be very scalable and have been widely accepted by the Internet community.
This graduation thesis is going firstly to investigate the current protocols for doing VoIP and in particular the Session Initiation Protocol.
Then peer-to-peer overlays are examined, devoting particular care to how integration with SIP can be made.
Afterwards, the focus will move on Network Address Translation (NAT). NAT is largely employed in SOHO networks as well as in big networks installations, because it reduces the need of public IP addresses and is believed to increase network security. However it requires many protocols to be modified to work correctly. NAT traversal techniques will be analyzed, along with the issues that NAT creates for SIP and P2P protocols.
In order to perform NAT traversal, a public rendez-vous point is needed. A methodology to build a distributed relay service over a pure peer-to-peer network will be proposed and validated by means of statistical analysis and simulation
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