Frédérique Oggier

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— 1 We study the MIMO wiretap channel, a MIMO broadcast channel where the transmitter sends some confidential information to one user which is a legitimate receiver, while the other user is an eavesdropper. Perfect secrecy is achieved when the transmitter and the legitimate receiver can communicate at some positive rate, while ensuring that the eavesdropper(More)
A recent line of work on lattice codes for Gaussian wiretap channels introduced a new lattice invariant called secrecy gain as a code design criterion which captures the confusion that lattice coding produces at an eavesdropper. Following up the study of unimodular lattice wiretap codes (Lin and Oggier in IEEE Trans Inf Theory 59(6):3295–3303, 2013), this(More)
In this article, we provide new methods to look for lightweight MDS matrices, and in particular involutory ones. By proving many new properties and equivalence classes for various MDS matrices constructions such as circulant, Hadamard, Cauchy and Hadamard-Cauchy, we exhibit new search algorithms that greatly reduce the search space and make lightweight MDS(More)
In this paper we study the problem of storing reliably an archive of versioned data. Specifically, we focus on systems where the differences (deltas) between subsequent versions rather than the whole objects are stored—a typical model for storing versioned data. For reliability, we propose erasure encoding techniques that exploit the sparsity of information(More)
Erasure coding has become an integral part of the storage infrastructure in data-centers and cloud backends—since it provides significantly higher fault tolerance for substantially lower storage overhead compared to a naive approach like n-way replication. Fault tolerance refers to the ability to achieve very high availability despite (temporary) failures,(More)
Networked distributed data storage systems are essential to deal with the needs of storing massive volumes of data. Dependability of such a system relies on its fault tolerance (data should be available in case of node failures) as well as its maintainability (its ability to repair lost data to ensure redundancy replenishment over time). Erasure codes(More)
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