46,171 research outputs found
A Churn for the Better: Localizing Censorship using Network-level Path Churn and Network Tomography
Recent years have seen the Internet become a key vehicle for citizens around
the globe to express political opinions and organize protests. This fact has
not gone unnoticed, with countries around the world repurposing network
management tools (e.g., URL filtering products) and protocols (e.g., BGP, DNS)
for censorship. However, repurposing these products can have unintended
international impact, which we refer to as "censorship leakage". While there
have been anecdotal reports of censorship leakage, there has yet to be a
systematic study of censorship leakage at a global scale. In this paper, we
combine a global censorship measurement platform (ICLab) with a general-purpose
technique -- boolean network tomography -- to identify which AS on a network
path is performing censorship. At a high-level, our approach exploits BGP churn
to narrow down the set of potential censoring ASes by over 95%. We exactly
identify 65 censoring ASes and find that the anomalies introduced by 24 of the
65 censoring ASes have an impact on users located in regions outside the
jurisdiction of the censoring AS, resulting in the leaking of regional
censorship policies
Supporting Cyber-Physical Systems with Wireless Sensor Networks: An Outlook of Software and Services
Sensing, communication, computation and control technologies are the essential building blocks of a cyber-physical system (CPS). Wireless sensor networks (WSNs) are a way to support CPS as they provide fine-grained spatial-temporal sensing, communication and computation at a low premium of cost and power. In this article, we explore the fundamental concepts guiding the design and implementation of WSNs. We report the latest developments in WSN software and services for meeting existing requirements and newer demands; particularly in the areas of: operating system, simulator and emulator, programming abstraction, virtualization, IP-based communication and security, time and location, and network monitoring and management. We also reflect on the ongoing
efforts in providing dependable assurances for WSN-driven CPS. Finally, we report on its applicability with a case-study on smart buildings
SecMon: End-to-End Quality and Security Monitoring System
The Voice over Internet Protocol (VoIP) is becoming a more available and
popular way of communicating for Internet users. This also applies to
Peer-to-Peer (P2P) systems and merging these two have already proven to be
successful (e.g. Skype). Even the existing standards of VoIP provide an
assurance of security and Quality of Service (QoS), however, these features are
usually optional and supported by limited number of implementations. As a
result, the lack of mandatory and widely applicable QoS and security guaranties
makes the contemporary VoIP systems vulnerable to attacks and network
disturbances. In this paper we are facing these issues and propose the SecMon
system, which simultaneously provides a lightweight security mechanism and
improves quality parameters of the call. SecMon is intended specially for VoIP
service over P2P networks and its main advantage is that it provides
authentication, data integrity services, adaptive QoS and (D)DoS attack
detection. Moreover, the SecMon approach represents a low-bandwidth consumption
solution that is transparent to the users and possesses a self-organizing
capability. The above-mentioned features are accomplished mainly by utilizing
two information hiding techniques: digital audio watermarking and network
steganography. These techniques are used to create covert channels that serve
as transport channels for lightweight QoS measurement's results. Furthermore,
these metrics are aggregated in a reputation system that enables best route
path selection in the P2P network. The reputation system helps also to mitigate
(D)DoS attacks, maximize performance and increase transmission efficiency in
the network.Comment: Paper was presented at 7th international conference IBIZA 2008: On
Computer Science - Research And Applications, Poland, Kazimierz Dolny
31.01-2.02 2008; 14 pages, 5 figure
An Empirical Study of the I2P Anonymity Network and its Censorship Resistance
Tor and I2P are well-known anonymity networks used by many individuals to
protect their online privacy and anonymity. Tor's centralized directory
services facilitate the understanding of the Tor network, as well as the
measurement and visualization of its structure through the Tor Metrics project.
In contrast, I2P does not rely on centralized directory servers, and thus
obtaining a complete view of the network is challenging. In this work, we
conduct an empirical study of the I2P network, in which we measure properties
including population, churn rate, router type, and the geographic distribution
of I2P peers. We find that there are currently around 32K active I2P peers in
the network on a daily basis. Of these peers, 14K are located behind NAT or
firewalls.
Using the collected network data, we examine the blocking resistance of I2P
against a censor that wants to prevent access to I2P using address-based
blocking techniques. Despite the decentralized characteristics of I2P, we
discover that a censor can block more than 95% of peer IP addresses known by a
stable I2P client by operating only 10 routers in the network. This amounts to
severe network impairment: a blocking rate of more than 70% is enough to cause
significant latency in web browsing activities, while blocking more than 90% of
peer IP addresses can make the network unusable. Finally, we discuss the
security consequences of the network being blocked, and directions for
potential approaches to make I2P more resistant to blocking.Comment: 14 pages, To appear in the 2018 Internet Measurement Conference
(IMC'18
PICES Press, Vol. 19, No. 1, Winter 2011
âą2010 PICES Science: A Note from the Former Science Board Chairman (pp. 1-4)
âą2010 PICES Awards (pp. 5-7)
âąThe First Year of FUTURE: A Progress Report (pp. 8-13)
âąNew Chairmen in PICES (pp. 14-19)
âąPacific Ocean Interior Carbon Data Synthesis, PACIFICA, in Progress (pp. 20-23)
âą2011 PICES Calendar (p. 23)
âąEcosystems 2010: Global Progress on Ecosystem-based Fisheries Management (pp. 24-26)
âąPICES 2010 Rapid Assessment Survey (pp. 27-29)
âąPICES Workshop on âAn Introduction to Rapid Assessment Survey Methodologies for Application in Developing Countriesâ (pp. 30-31)
âąThe State of the Western North Pacific in the First Half of 2010 (pp. 32-34)
âąPICES Interns (p. 34)
âąThe State of the Bering Sea in 2010 (pp. 35-37)
âąThe State of the Northeast Pacific in 2010 (pp. 38-40
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