293 research outputs found
The geopolitics behind the routes data travels: a case study of Iran
The global expansion of the Internet has brought many challenges to
geopolitics. Cyberspace is a space of strategic priority for many states.
Understanding and representing its geography remains an ongoing challenge.
Nevertheless, we need to comprehend Cyberspace as a space organized by humans
to analyse the strategies of the actors. This geography requires a
multidisciplinary dialogue associating geopolitics, computer science and
mathematics. Cyberspace is represented as three superposed and interacting
layers: the physical, logical, and informational layers. This paper focuses on
the logical layer through an analysis of the structure of connectivity and the
Border Gateway Protocol (BGP). This protocol determines the routes taken by the
data. It has been leveraged by countries to control the flow of information,
and to block the access to contents (going up to full disruption of the
internet) or for active strategic purposes such as hijacking traffic or
attacking infrastructures. Several countries have opted for a BGP strategy. The
goal of this study is to characterize these strategies, to link them to current
architectures and to understand their resilience in times of crisis. Our
hypothesis is that there are connections between the network architecture
shaped through BGP, and strategy of stakeholders at a national level. We chose
to focus on the case of Iran because, Iran presents an interesting BGP
architecture and holds a central position in the connectivity of the Middle
East. Moreover, Iran is at the center of several ongoing geopolitical rifts.
Our observations make it possible to infer three ways in which Iran could have
used BGP to achieve its strategic goals: the pursuit of a self-sustaining
national Internet with controlled borders; the will to set up an Iranian
Intranet to facilitate censorship; and the leverage of connectivity as a tool
of regional influence
Centralized vs Decentralized Multi-Agent Guesswork
We study a notion of guesswork, where multiple agents intend to launch a
coordinated brute-force attack to find a single binary secret string, and each
agent has access to side information generated through either a BEC or a BSC.
The average number of trials required to find the secret string grows
exponentially with the length of the string, and the rate of the growth is
called the guesswork exponent. We compute the guesswork exponent for several
multi-agent attacks. We show that a multi-agent attack reduces the guesswork
exponent compared to a single agent, even when the agents do not exchange
information to coordinate their attack, and try to individually guess the
secret string using a predetermined scheme in a decentralized fashion. Further,
we show that the guesswork exponent of two agents who do coordinate their
attack is strictly smaller than that of any finite number of agents
individually performing decentralized guesswork.Comment: Accepted at IEEE International Symposium on Information Theory (ISIT)
201
From the Information Bottleneck to the Privacy Funnel
We focus on the privacy-utility trade-off encountered by users who wish to
disclose some information to an analyst, that is correlated with their private
data, in the hope of receiving some utility. We rely on a general privacy
statistical inference framework, under which data is transformed before it is
disclosed, according to a probabilistic privacy mapping. We show that when the
log-loss is introduced in this framework in both the privacy metric and the
distortion metric, the privacy leakage and the utility constraint can be
reduced to the mutual information between private data and disclosed data, and
between non-private data and disclosed data respectively. We justify the
relevance and generality of the privacy metric under the log-loss by proving
that the inference threat under any bounded cost function can be upper-bounded
by an explicit function of the mutual information between private data and
disclosed data. We then show that the privacy-utility tradeoff under the
log-loss can be cast as the non-convex Privacy Funnel optimization, and we
leverage its connection to the Information Bottleneck, to provide a greedy
algorithm that is locally optimal. We evaluate its performance on the US census
dataset
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