Séminaire de Cryptographie

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Suba Subbalakshmi

Error Correction and Encryption: Can they be combined?

Achieving secure and reliable communication in a wireless network is especially challenging when the end devices are energy constrained. Traditionally, forward error correcting codes (FECs) and encryption have been used to correct errors and provide secrecy respectively, in a tandem system. This conventional approach could be potentially less efficient than a joint system (where both functionalities are combined into a single paradigm). The key question is: can the two operations be combined safely and if so what are the impacts of such a joint construction on both error correction capability as well as security?

In this talk we will show that it is indeed possible to combine error correction and encryption in the specific case of block ciphers. The core of this construction is a new class of maximum distance separable (MDS) codes, which we call high diffusion (HD) codes, that incorporate both a criterion for optimal diffusion as well as a criterion for error correction. We will present the fundamental ideas behind HD codes and discuss the construction of the codes and block ciphers based on these codes. Security and error correction capabilities of the joint system will be discussed. Stream mode construction of the cipher will also be presented along with some simulation results.