Privacy is of the utmost importance in genomic matching. Therefore a number of privacy-preserving protocols have been presented using secure computation. Nevertheless, none of these protocols prevents inferences from the result. Goodrich has shown that this resulting information is sufficient for an effective attack on genome databases. In this paper we present an approach that can detect and mitigate such an attack on encrypted messages while still preserving the privacy of both parties. Note that randomization, e.g.~using differential privacy, will almost certainly destroy the utility of the matching result. We combine two known cryptographic primitives -- secure computation of the edit distance and fuzzy commitments -- in order to prevent submission of similar genome sequences. Particularly, we contribute an efficient zero-knowledge proof that the same input has been used in both primitives. We show that using our approach it is feasible to preserve privacy in genome matching and also detect and mitigate Goodrich's attack.
Los motivos históricos y económicos que han llevado a programar el protocolo Bitcoin se encuentran en la actualidad con una interesante fase evolutiva de los algoritmos de encriptación para la identificación de datos y la transmisión de derechos, tratándose de un sistema que presenta aspectos jurídicos dignos de mención.
A sensor network typically refers to a collection of sensor nodes equipped with sensing, communication and processing capabilities. It brings an opportunity to solve many difficult problems including real time monitoring, tracking, and controlling. While the applications of sensor networking become many and varied, security has always been one of the major concerns in real deployments. In this dissertation, we design physical primitives for secure communication in wireless sensor networks, and develop a wireless security framework to provide conventional security services. We investigate the feasibility of achieving perfect secrecy and information authenticity without shared secrets via two physical primitives: (i) cooperative jamming primitive, where we introduce a secure coding problem in which not only the sender but also the receiver participates in the coding. In essence, the receiver’s role is to selectively jam the sender’s transmission at the level of bits, bytes, or packets. We then design a class of secure codes, called “dialog codes”, for diverse channel models and receiver models. (ii) spatial verification primitive, where we exploit the spatial signature induced by the radio communications of a node on its neighboring nodes, and design a spatial primitive that robustly and efficiently validates the authenticity of the source of messages. To address trust initialization, we propose a zero knowledge proof alternative that allows bootstrapping trust among individuals in a distributed way.
Ivan Damgård, Torben Pryds Pedersen, Birgit Pfitzmann
<p>We present and compare definitions of the notion of "statistically<br />hiding" protocols, and we propose a novel statistically hiding commitment<br />scheme. Informally, a protocol statistically hides a secret if a<br />computationally unlimited adversary who conducts the protocol with<br />the owner of the secret learns almost nothing about it. One definition<br />is based on the L1-norm distance between probability distributions,<br />the other on information theory. We prove that the two definitions are<br />essentially equivalent. For completeness, we also show that statistical<br />counterparts of definitions of computational secrecy are essentially<br />equivalent to our main definitions. Commitment schemes are an important<br /> cryptologic primitive. Their purpose is to commit one party to a certain value,<br /> while hiding this value from the other party until some later time.<br /> We present a statistically<br />hiding commitment scheme allowing commitment to many<br />bits. The commitment and reveal protocols of this scheme are constant<br />round, and the size of a commitment is independent of the number of<br />bits committed to. This also holds for the total communication complexity,<br />except of course for the bits needed to send the secret when it<br />is revealed. The proof of the hiding property exploits the equivalence<br />of the two definitions.</p><p>Index terms -- Cryptology, Shannon theory, unconditional security,<br />statistically hiding, multi-bit commitment, similarity of ensembles<br />of distributions, zero-knowledge, protocols.</p><p> </p>