605 research outputs found
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
Securing Information-Centric Networking without negating Middleboxes
Information-Centric Networking is a promising networking paradigm that
overcomes many of the limitations of current networking architectures. Various
research efforts investigate solutions for securing ICN. Nevertheless, most of
these solutions relax security requirements in favor of network performance. In
particular, they weaken end-user privacy and the architecture's tolerance to
security breaches in order to support middleboxes that offer services such as
caching and content replication. In this paper, we adapt TLS, a widely used
security standard, to an ICN context. We design solutions that allow session
reuse and migration among multiple stakeholders and we propose an extension
that allows authorized middleboxes to lawfully and transparently intercept
secured communications.Comment: 8th IFIP International Conference on New Technologies, Mobility &
Security, IFIP, 201
TorKameleon: Improving Tor's Censorship Resistance With K-anonymization and Media-based Covert Channels
Anonymity networks like Tor greatly improve online privacy but are
susceptible to correlation attacks from state-level adversaries and Internet
censors. To enhance privacy, covert channels encapsulated in media protocols,
particularly WebRTC-based encapsulation, have shown promise against passive
traffic correlation attacks. However, their effectiveness against active
correlation attacks has not been explored, and compatibility with Tor remains
limited. This paper introduces TorKameleon, a censorship evasion solution that
protects Tor users from passive and active correlation attacks. It incorporates
K-anonymization techniques to fragment and reroute traffic through multiple
paths formed by multiple proxies and uses covert WebRTC-based channels or TLS
tunnels to encapsulate user traffic. The developed prototype has undergone
extensive validation for performance and resilience against correlation
attacks, showcasing its effectiveness
SECURITY AND PRIVACY ISSUES IN MOBILE NETWORKS, DIFFICULTIES AND SOLUTIONS
Mobile communication is playing a vital role in the daily life for the last two decades; in turn its fields gained the research attention, which led to the introduction of new technologies, services and applications. These new added facilities aimed to ease the connectivity and reachability; on the other hand, many security and privacy concerns were not taken into consideration. This opened the door for the malicious activities to threaten the deployed systems and caused vulnerabilities for users, translated in the loss of valuable data and major privacy invasions. Recently, many attempts have been carried out to handle these concerns, such as improving systems’ security and implementing different privacy enhancing mechanisms. This research addresses these problems and provides a mean to preserve privacy in particular. In this research, a detailed description and analysis of the current security and privacy situation in the deployed systems is given. As a result, the existing shortages within these systems are pointed out, to be mitigated in development. Finally a privacy preserving prototype model is proposed. This research has been conducted as an extensive literature review about the most relevant references and researches in the field, using the descriptive and evaluative research methodologies. The main security models, parameters, modules and protocols are presented, also a detailed description of privacy and its related arguments, dimensions and factors is given. The findings include that mobile networks’ security along with users are vulnerable due to the weaknesses of the key exchange procedures, the difficulties that face possession, repudiation, standardization, compatibility drawbacks and lack of configurability. It also includes the need to implement new mechanisms to protect security and preserve privacy, which include public key cryptography, HIP servers, IPSec, TLS, NAT and DTLS-SRTP. Last but not least, it shows that privacy is not absolute and it has many conflicts, also privacy requires sophisticated systems, which increase the load and cost of the system.fi=Opinnäytetyö kokotekstinä PDF-muodossa.|en=Thesis fulltext in PDF format.|sv=Lärdomsprov tillgängligt som fulltext i PDF-format
TORKAMELEON. IMPROVING TOR’S CENSORSHIP RESISTANCE WITH K-ANONYMIZATION MEDIA MORPHING COVERT INPUT CHANNELS
Anonymity networks such as Tor and other related tools are powerful means of increas-
ing the anonymity and privacy of Internet users’ communications. Tor is currently the
most widely used solution by whistleblowers to disclose confidential information and
denounce censorship measures, including violations of civil rights, freedom of expres-
sion, or guarantees of free access to information. However, recent research studies have
shown that Tor is vulnerable to so-called powerful correlation attacks carried out by
global adversaries or collaborative Internet censorship parties. In the Tor ”arms race”
scenario, we can see that as new censorship, surveillance, and deep correlation tools have
been researched, new, improved solutions for preserving anonymity have also emerged.
In recent research proposals, unobservable encapsulation of IP packets in covert media
channels is one of the most promising defenses against such threat models. They leverage
WebRTC-based covert channels as a robust and practical approach against powerful traf-
fic correlation analysis. At the same time, these solutions are difficult to combat through
the traffic-blocking measures commonly used by censorship authorities.
In this dissertation, we propose TorKameleon, a censorship evasion solution de-
signed to protect Tor users with increased censorship resistance against powerful traffic
correlation attacks executed by global adversaries. The system is based on flexible K-
anonymization input circuits that can support TLS tunneling and WebRTC-based covert
channels before forwarding users’ original input traffic to the Tor network. Our goal
is to protect users from machine and deep learning correlation attacks between incom-
ing user traffic and observed traffic at different Tor network relays, such as middle and
egress relays. TorKameleon is the first system to implement a Tor pluggable transport
based on parameterizable TLS tunneling and WebRTC-based covert channels. We have
implemented the TorKameleon prototype and performed extensive validations to ob-
serve the correctness and experimental performance of the proposed solution in the Tor
environment. With these evaluations, we analyze the necessary tradeoffs between the
performance of the standard Tor network and the achieved effectiveness and performance
of TorKameleon, capable of preserving the required unobservability properties.Redes de anonimização como o Tor e soluções ou ferramentas semelhantes são meios
poderosos de aumentar a anonimidade e a privacidade das comunicações de utilizadores
da Internet . O Tor Ă© atualmente a rede de anonimato mais utilizada por delatores para
divulgar informações confidenciais e denunciar medidas de censura tais como violações
de direitos civis e da liberdade de expressĂŁo, ou falhas nas garantias de livre acesso Ă
informação. No entanto, estudos recentes mostram que o Tor é vulnerável a adversários
globais ou a entidades que colaboram entre si para garantir a censura online. Neste
cenário competitivo e de jogo do “gato e do rato”, Ă© possĂvel verificar que Ă medida que
novas soluções de censura e vigilância são investigadas, novos sistemas melhorados para
a preservação de anonimato são também apresentados e refinados. O encapsulamento de
pacotes IP em tĂşneis encapsulados em protocolos de media sĂŁo uma das mais promissoras
soluções contra os novos modelos de ataque à anonimidade. Estas soluções alavancam
canais encobertos em protocolos de media baseados em WebRTC para resistir a poderosos
ataques de correlação de tráfego e a medidas de bloqueios normalmente usadas pelos
censores.
Nesta dissertação propomos o TorKameleon, uma solução desenhada para protoger
os utilizadores da rede Tor contra os mais recentes ataques de correlação feitos por um
modelo de adversário global. O sistema é baseado em estratégias de anonimização e
reencaminhamento do tráfego do utilizador através de K nós, utilizando também encap-
sulamento do tráfego em canais encobertos em túneis TLS ou WebRTC. O nosso objetivo
é proteger os utilizadores da rede Tor de ataques de correlação implementados através
de modelos de aprendizagem automática feitos entre o tráfego do utilizador que entra
na rede Tor e esse mesmo tráfego noutro segmento da rede, como por exemplo nos nós
de saĂda da rede. O TorKameleon Ă© o primeiro sistema a implementar um Tor pluggable
transport parametrizável, baseado em túneis TLS ou em canais encobertos em protocolos
media. Implementamos um protótipo do sistema e realizamos uma extensa avalição expe-
rimental, inserindo a solução no ambiente da rede Tor. Com base nestas avaliações, anali-
zamos o tradeoff necessário entre a performance da rede Tor e a eficácia e a performance
obtida do TorKameleon, que garante as propriedades de preservação de anonimato
Contributions to the privacy provisioning for federated identity management platforms
Identity information, personal data and user’s profiles are key assets for organizations
and companies by becoming the use of identity management (IdM) infrastructures a prerequisite
for most companies, since IdM systems allow them to perform their business
transactions by sharing information and customizing services for several purposes in more
efficient and effective ways.
Due to the importance of the identity management paradigm, a lot of work has been done
so far resulting in a set of standards and specifications. According to them, under the
umbrella of the IdM paradigm a person’s digital identity can be shared, linked and reused
across different domains by allowing users simple session management, etc. In this way,
users’ information is widely collected and distributed to offer new added value services
and to enhance availability. Whereas these new services have a positive impact on users’
life, they also bring privacy problems.
To manage users’ personal data, while protecting their privacy, IdM systems are the ideal
target where to deploy privacy solutions, since they handle users’ attribute exchange.
Nevertheless, current IdM models and specifications do not sufficiently address comprehensive
privacy mechanisms or guidelines, which enable users to better control over the
use, divulging and revocation of their online identities. These are essential aspects, specially
in sensitive environments where incorrect and unsecured management of user’s data
may lead to attacks, privacy breaches, identity misuse or frauds.
Nowadays there are several approaches to IdM that have benefits and shortcomings, from
the privacy perspective.
In this thesis, the main goal is contributing to the privacy provisioning for federated
identity management platforms. And for this purpose, we propose a generic architecture
that extends current federation IdM systems. We have mainly focused our contributions
on health care environments, given their particularly sensitive nature. The two main
pillars of the proposed architecture, are the introduction of a selective privacy-enhanced
user profile management model and flexibility in revocation consent by incorporating an
event-based hybrid IdM approach, which enables to replace time constraints and explicit
revocation by activating and deactivating authorization rights according to events. The
combination of both models enables to deal with both online and offline scenarios, as well
as to empower the user role, by letting her to bring together identity information from
different sources.
Regarding user’s consent revocation, we propose an implicit revocation consent mechanism
based on events, that empowers a new concept, the sleepyhead credentials, which
is issued only once and would be used any time. Moreover, we integrate this concept
in IdM systems supporting a delegation protocol and we contribute with the definition
of mathematical model to determine event arrivals to the IdM system and how they are
managed to the corresponding entities, as well as its integration with the most widely
deployed specification, i.e., Security Assertion Markup Language (SAML).
In regard to user profile management, we define a privacy-awareness user profile management
model to provide efficient selective information disclosure. With this contribution a
service provider would be able to accesses the specific personal information without being
able to inspect any other details and keeping user control of her data by controlling
who can access. The structure that we consider for the user profile storage is based on
extensions of Merkle trees allowing for hash combining that would minimize the need of
individual verification of elements along a path. An algorithm for sorting the tree as we
envision frequently accessed attributes to be closer to the root (minimizing the access’
time) is also provided.
Formal validation of the above mentioned ideas has been carried out through simulations
and the development of prototypes. Besides, dissemination activities were performed in
projects, journals and conferences.Programa Oficial de Doctorado en IngenierĂa TelemáticaPresidente: MarĂa Celeste Campo Vázquez.- Secretario: MarĂa Francisca Hinarejos Campos.- Vocal: Ă“scar Esparza MartĂ
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