8,239 research outputs found
Privately Connecting Mobility to Infectious Diseases via Applied Cryptography
Human mobility is undisputedly one of the critical factors in infectious
disease dynamics. Until a few years ago, researchers had to rely on static data
to model human mobility, which was then combined with a transmission model of a
particular disease resulting in an epidemiological model. Recent works have
consistently been showing that substituting the static mobility data with
mobile phone data leads to significantly more accurate models. While prior
studies have exclusively relied on a mobile network operator's subscribers'
aggregated data, it may be preferable to contemplate aggregated mobility data
of infected individuals only. Clearly, naively linking mobile phone data with
infected individuals would massively intrude privacy. This research aims to
develop a solution that reports the aggregated mobile phone location data of
infected individuals while still maintaining compliance with privacy
expectations. To achieve privacy, we use homomorphic encryption, zero-knowledge
proof techniques, and differential privacy. Our protocol's open-source
implementation can process eight million subscribers in one and a half hours.
Additionally, we provide a legal analysis of our solution with regards to the
EU General Data Protection Regulation.Comment: Added differentlial privacy experiments and new benchmark
APPLIED CRYPTOGRAPHY IN EMBEDDED SYSTEMS
Nowadays, it is widely recognized that data security will play a central role in the design of IT devices. There are more than billion wireless users by now; it faces a growing need for security of embedded applications.
This thesis focuses on the basic concept; properties and performance of symmetric and asymmetric cryptosystems. In this thesis, different encryption and decryption algorithms have been implemented on embedded systems. Moreover, the execution time and power consumption of each cryptography method have been evaluated as key performance indicators. CAESAR and AES are implemented for the microcontroller (ATmega8515). The STK 500 board is used for programming of the ATmega8515. Furthermore it is used for the communication between the microcontroller and PC to obtain the performance advantages of the cryptography methods. Time and power consumption are measured by using an oscilloscope and a multimeter. Furthermore the performance of different cryptography methods are compared.fi=Opinnäytetyö kokotekstinä PDF-muodossa.|en=Thesis fulltext in PDF format.|sv=Lärdomsprov tillgängligt som fulltext i PDF-format
IMPROVING SMART GRID SECURITY USING MERKLE TREES
Abstract—Presently nations worldwide are starting to convert their aging electrical power infrastructures into modern, dynamic power grids. Smart Grid offers much in the way of efficiencies and robustness to the electrical power grid, however its heavy reliance on communication networks will leave it more vulnerable to attack than present day grids. This paper looks at the threat to public key cryptography systems from a fully realized quantum computer and how this could impact the Smart Grid. We argue for the use of Merkle Trees in place of public key cryptography for authentication of devices in wireless mesh networks that are used in Smart Grid applications
Public Evidence from Secret Ballots
Elections seem simple---aren't they just counting? But they have a unique,
challenging combination of security and privacy requirements. The stakes are
high; the context is adversarial; the electorate needs to be convinced that the
results are correct; and the secrecy of the ballot must be ensured. And they
have practical constraints: time is of the essence, and voting systems need to
be affordable and maintainable, and usable by voters, election officials, and
pollworkers. It is thus not surprising that voting is a rich research area
spanning theory, applied cryptography, practical systems analysis, usable
security, and statistics. Election integrity involves two key concepts:
convincing evidence that outcomes are correct and privacy, which amounts to
convincing assurance that there is no evidence about how any given person
voted. These are obviously in tension. We examine how current systems walk this
tightrope.Comment: To appear in E-Vote-Id '1
A Formula That Generates Hash Collisions
We present an explicit formula that produces hash collisions for the
Merkle-Damg{\aa}rd construction. The formula works for arbitrary choice of
message block and irrespective of the standardized constants used in hash
functions, although some padding schemes may cause the formula to fail. This
formula bears no obvious practical implications because at least one of any
pair of colliding messages will have length double exponential in the security
parameter. However, due to ambiguity in existing definitions of collision
resistance, this formula arguably breaks the collision resistance of some hash
functions.Comment: 10 page
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