About the Security of Ciphers (Semantic Security and Pseudo-Random Permutations).


Duong Hieu Phan and David Pointcheval.


Abstract: Probabilistic symmetric encryption have already been widely studied, from a theoretical point of view. Nevertheless, many applications require length-preserving encryption, to be patched at a minimal cost to include privacy without modifying the format (e.g. encrypted filesystems). In this paper, we thus consider the security notions for length-preserving, deterministic and symmetric encryption schemes, also termed ciphers: semantic security under lunchtime and challenge-adaptive adversaries. We furthermore provide some relations for this notion between different models of adversaries, and the more classical security notions for ciphers: pseudo-random permutations (PRP) and super pseudo-random permutations (SPRP).

Ref: Proceeding of SAC '04, Lecture Notes in Computer Science Vol. 3357, pages 185-200, Springer-Verlag, 2004.

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