Non-Malleable Codes for Space-Bounded Tampering [chapter]

Sebastian Faust, Kristina Hostáková, Pratyay Mukherjee, Daniele Venturi
2017 Lecture Notes in Computer Science  
Non-malleable codes-introduced by Dziembowski, Pietrzak and Wichs at ICS 2010are key-less coding schemes in which mauling attempts to an encoding of a given message, w.r.t. some class of tampering adversaries, result in a decoded value that is either identical or unrelated to the original message. Such codes are very useful for protecting arbitrary cryptographic primitives against tampering attacks against the memory. Clearly, non-malleability is hopeless if the class of tampering adversaries
more » ... cludes the decoding and encoding algorithm. To circumvent this obstacle, the majority of past research focused on designing non-malleable codes for various tampering classes, albeit assuming that the adversary is unable to decode. Nonetheless, in many concrete settings, this assumption is not realistic. In this paper, we explore one particular such scenario where the class of tampering adversaries naturally includes the decoding (but not the encoding) algorithm. In particular, we consider the class of adversaries that are restricted in terms of memory/space. Our main contributions can be summarized as follows: * variant of soundness. As we show, our paradigm can be instantiated by extending the analysis of the PoS construction by Ren and Devadas (TCC 2016-A), based on so-called stacks of localized expander graphs. • Finally, we show that our flavor of non-malleability yields a natural security guarantee against memory tampering attacks, where one can trade a small amount of leakage on the secret key for protection against space-bounded tampering attacks.
doi:10.1007/978-3-319-63715-0_4 fatcat:r2bgcran5rauhjthyao7ixfj5e