147,524 research outputs found
How Far Removed Are You? Scalable Privacy-Preserving Estimation of Social Path Length with Social PaL
Social relationships are a natural basis on which humans make trust
decisions. Online Social Networks (OSNs) are increasingly often used to let
users base trust decisions on the existence and the strength of social
relationships. While most OSNs allow users to discover the length of the social
path to other users, they do so in a centralized way, thus requiring them to
rely on the service provider and reveal their interest in each other. This
paper presents Social PaL, a system supporting the privacy-preserving discovery
of arbitrary-length social paths between any two social network users. We
overcome the bootstrapping problem encountered in all related prior work,
demonstrating that Social PaL allows its users to find all paths of length two
and to discover a significant fraction of longer paths, even when only a small
fraction of OSN users is in the Social PaL system - e.g., discovering 70% of
all paths with only 40% of the users. We implement Social PaL using a scalable
server-side architecture and a modular Android client library, allowing
developers to seamlessly integrate it into their apps.Comment: A preliminary version of this paper appears in ACM WiSec 2015. This
is the full versio
Dynamics, robustness and fragility of trust
Trust is often conveyed through delegation, or through recommendation. This
makes the trust authorities, who process and publish trust recommendations,
into an attractive target for attacks and spoofing. In some recent empiric
studies, this was shown to lead to a remarkable phenomenon of *adverse
selection*: a greater percentage of unreliable or malicious web merchants were
found among those with certain types of trust certificates, then among those
without. While such findings can be attributed to a lack of diligence in trust
authorities, or even to conflicts of interest, our analysis of trust dynamics
suggests that public trust networks would probably remain vulnerable even if
trust authorities were perfectly diligent. The reason is that the process of
trust building, if trust is not breached too often, naturally leads to
power-law distributions: the rich get richer, the trusted attract more trust.
The evolutionary processes with such distributions, ubiquitous in nature, are
known to be robust with respect to random failures, but vulnerable to adaptive
attacks. We recommend some ways to decrease the vulnerability of trust
building, and suggest some ideas for exploration.Comment: 17 pages; simplified the statement and the proof of the main theorem;
FAST 200
Blindspot: Indistinguishable Anonymous Communications
Communication anonymity is a key requirement for individuals under targeted
surveillance. Practical anonymous communications also require
indistinguishability - an adversary should be unable to distinguish between
anonymised and non-anonymised traffic for a given user. We propose Blindspot, a
design for high-latency anonymous communications that offers
indistinguishability and unobservability under a (qualified) global active
adversary. Blindspot creates anonymous routes between sender-receiver pairs by
subliminally encoding messages within the pre-existing communication behaviour
of users within a social network. Specifically, the organic image sharing
behaviour of users. Thus channel bandwidth depends on the intensity of image
sharing behaviour of users along a route. A major challenge we successfully
overcome is that routing must be accomplished in the face of significant
restrictions - channel bandwidth is stochastic. We show that conventional
social network routing strategies do not work. To solve this problem, we
propose a novel routing algorithm. We evaluate Blindspot using a real-world
dataset. We find that it delivers reasonable results for applications requiring
low-volume unobservable communication.Comment: 13 Page
All liaisons are dangerous when all your friends are known to us
Online Social Networks (OSNs) are used by millions of users worldwide.
Academically speaking, there is little doubt about the usefulness of
demographic studies conducted on OSNs and, hence, methods to label unknown
users from small labeled samples are very useful. However, from the general
public point of view, this can be a serious privacy concern. Thus, both topics
are tackled in this paper: First, a new algorithm to perform user profiling in
social networks is described, and its performance is reported and discussed.
Secondly, the experiments --conducted on information usually considered
sensitive-- reveal that by just publicizing one's contacts privacy is at risk
and, thus, measures to minimize privacy leaks due to social graph data mining
are outlined.Comment: 10 pages, 5 table
Governing by internet architecture
In the past thirty years, the exponential rise in the number of Internet users around the word and the intensive use of the digital networks have brought to light crucial political issues. Internet is now the object of regulations. Namely, it is a policy domain. Yet, its own architecture represents a new regulative structure, one deeply affecting politics and everyday life. This article considers some of the main transformations of the Internet induced by privatization and militarization processes, as well as their consequences on societies and human beings.En los últimos treinta años ha crecido de manera exponencial el número de usuarios de Internet alrededor del mundo y el uso intensivo de conexiones digitales ha traído a la luz cuestiones políticas cruciales. Internet es ahora objeto de regulaciones. Es decir, es un ámbito de la política. Aún su propia arquitectura representa una nueva estructura reguladora, que afecta profundamente la política y la vida cotidiana. Este artículo considera algunas de las principales transformaciones de Internet inducida por procesos de privatización y militarización, como también sus consecuencias en las sociedades y en los seres humanos
X-Vine: Secure and Pseudonymous Routing Using Social Networks
Distributed hash tables suffer from several security and privacy
vulnerabilities, including the problem of Sybil attacks. Existing social
network-based solutions to mitigate the Sybil attacks in DHT routing have a
high state requirement and do not provide an adequate level of privacy. For
instance, such techniques require a user to reveal their social network
contacts. We design X-Vine, a protection mechanism for distributed hash tables
that operates entirely by communicating over social network links. As with
traditional peer-to-peer systems, X-Vine provides robustness, scalability, and
a platform for innovation. The use of social network links for communication
helps protect participant privacy and adds a new dimension of trust absent from
previous designs. X-Vine is resilient to denial of service via Sybil attacks,
and in fact is the first Sybil defense that requires only a logarithmic amount
of state per node, making it suitable for large-scale and dynamic settings.
X-Vine also helps protect the privacy of users social network contacts and
keeps their IP addresses hidden from those outside of their social circle,
providing a basis for pseudonymous communication. We first evaluate our design
with analysis and simulations, using several real world large-scale social
networking topologies. We show that the constraints of X-Vine allow the
insertion of only a logarithmic number of Sybil identities per attack edge; we
show this mitigates the impact of malicious attacks while not affecting the
performance of honest nodes. Moreover, our algorithms are efficient, maintain
low stretch, and avoid hot spots in the network. We validate our design with a
PlanetLab implementation and a Facebook plugin.Comment: 15 page
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