One-time hash steganography

In this paper we first generalize the steganography system model which Christian Cachin proposed, and specialize it to be suitable for computer oriented steganography systems. Based on this model, we introduce a new perfectly secure steganography scheme, one-time hash steganography, with which one can hide a secret bit into any cover-data that satisfies certain condition (partial recomputability). Finally we prove that there exists a perfectly secure steganography system with given cover-data source if and only if the cover-data source is partially recomputable to its sender.