21,481 research outputs found
Formally based semi-automatic implementation of an open security protocol
International audienceThis paper presents an experiment in which an implementation of the client side of the SSH Transport Layer Protocol (SSH-TLP) was semi-automatically derived according to a model-driven development paradigm that leverages formal methods in order to obtain high correctness assurance. The approach used in the experiment starts with the formalization of the protocol at an abstract level. This model is then formally proved to fulfill the desired secrecy and authentication properties by using the ProVerif prover. Finally, a sound Java implementation is semi-automatically derived from the verified model using an enhanced version of the Spi2Java framework. The resulting implementation correctly interoperates with third party servers, and its execution time is comparable with that of other manually developed Java SSH-TLP client implementations. This case study demonstrates that the adopted model-driven approach is viable even for a real security protocol, despite the complexity of the models needed in order to achieve an interoperable implementation
Provably-secure symmetric private information retrieval with quantum cryptography
Private information retrieval (PIR) is a database query protocol that
provides user privacy, in that the user can learn a particular entry of the
database of his interest but his query would be hidden from the data centre.
Symmetric private information retrieval (SPIR) takes PIR further by
additionally offering database privacy, where the user cannot learn any
additional entries of the database. Unconditionally secure SPIR solutions with
multiple databases are known classically, but are unrealistic because they
require long shared secret keys between the parties for secure communication
and shared randomness in the protocol. Here, we propose using quantum key
distribution (QKD) instead for a practical implementation, which can realise
both the secure communication and shared randomness requirements. We prove that
QKD maintains the security of the SPIR protocol and that it is also secure
against any external eavesdropper. We also show how such a classical-quantum
system could be implemented practically, using the example of a two-database
SPIR protocol with keys generated by measurement device-independent QKD.
Through key rate calculations, we show that such an implementation is feasible
at the metropolitan level with current QKD technology.Comment: 19 page
KeyForge: Mitigating Email Breaches with Forward-Forgeable Signatures
Email breaches are commonplace, and they expose a wealth of personal,
business, and political data that may have devastating consequences. The
current email system allows any attacker who gains access to your email to
prove the authenticity of the stolen messages to third parties -- a property
arising from a necessary anti-spam / anti-spoofing protocol called DKIM. This
exacerbates the problem of email breaches by greatly increasing the potential
for attackers to damage the users' reputation, blackmail them, or sell the
stolen information to third parties.
In this paper, we introduce "non-attributable email", which guarantees that a
wide class of adversaries are unable to convince any third party of the
authenticity of stolen emails. We formally define non-attributability, and
present two practical system proposals -- KeyForge and TimeForge -- that
provably achieve non-attributability while maintaining the important protection
against spam and spoofing that is currently provided by DKIM. Moreover, we
implement KeyForge and demonstrate that that scheme is practical, achieving
competitive verification and signing speed while also requiring 42% less
bandwidth per email than RSA2048
Distributed Random Process for a Large-Scale Peer-to-Peer Lottery
Most online lotteries today fail to ensure the verifiability of the random
process and rely on a trusted third party. This issue has received little
attention since the emergence of distributed protocols like Bitcoin that
demonstrated the potential of protocols with no trusted third party. We argue
that the security requirements of online lotteries are similar to those of
online voting, and propose a novel distributed online lottery protocol that
applies techniques developed for voting applications to an existing lottery
protocol. As a result, the protocol is scalable, provides efficient
verification of the random process and does not rely on a trusted third party
nor on assumptions of bounded computational resources. An early prototype
confirms the feasibility of our approach
Can Component/Service-Based Systems Be Proved Correct?
Component-oriented and service-oriented approaches have gained a strong
enthusiasm in industries and academia with a particular interest for
service-oriented approaches. A component is a software entity with given
functionalities, made available by a provider, and used to build other
application within which it is integrated. The service concept and its use in
web-based application development have a huge impact on reuse practices.
Accordingly a considerable part of software architectures is influenced; these
architectures are moving towards service-oriented architectures. Therefore
applications (re)use services that are available elsewhere and many
applications interact, without knowing each other, using services available via
service servers and their published interfaces and functionalities. Industries
propose, through various consortium, languages, technologies and standards.
More academic works are also undertaken concerning semantics and formalisation
of components and service-based systems. We consider here both streams of works
in order to raise research concerns that will help in building quality
software. Are there new challenging problems with respect to service-based
software construction? Besides, what are the links and the advances compared to
distributed systems?Comment: 16 page
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