Coding for Distributed Storage Systems

29/12/2015 - 11:00
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Abstract: 

 

In distributed storage systems (DSS) data is stored over a large number of storage nodes in such a way that a user can always retrieve the stored data, even if some storage nodes fail. To achieve such resilience against node failures, DSS introduce data redundancy based on different coding techniques. When a single node fails, the system performs node repair, i.e., reconstructs the data stored in the failed node in order to maintain the required level of redundancy.
In this talk we introduce a new approach to constructing different families of optimal codes for DSS via rank-metric codes. In the first part of the talk we deal with two important goals that guide the design of codes for DSS: reducing the repair bandwidth, i.e., the amount of data downloaded from the nodes during  node repair, and achieving locality, i.e., reducing the number of nodes participating in a node repair process. First, we present a construction of a new family of optimal locally repairable codes, which enable repair of a failed node while using only few other nodes. Second, we introduce a new class of codes which minimize repair bandwidth for given locality parameters.
In the second part of the talk we consider the problem of making DSS resilient to adversarial attacks. In such attacks, an adversary may gain read-only access to information stored in DSS (passive eavesdropper) or may modify it (active adversary). We present a novel construction of codes for DSS which provide perfect secrecy, i.e., codes which allow to store data without revealing any information to an eavesdropper. This construction is also based on rank-metric codes.

Bio:
Natalia Silberstein received her B.A. degree in Computer Science (cum laude), B.A. degree in  Mathematics (cum laude), M.Sc. degree in Applied Mathematics (summa cum laude), and Ph.D. degree in Computer Science from the Technion, in 2004, 2007, and 2011, respectively. She then spent two years as a postdoctoral fellow in the Wireless Networking and Communications Group, at the Department of Electrical and Computer Engineering at the University of Texas at Austin, USA. She is currently a postdoctoral fellow at the Computer Science Department at the Technion.
Her research focuses on coding for distributed storage systems, network coding, algebraic error-correcting codes, applications of combinatorial designs and graphs to coding theory.