A novel secret sharing scheme, called the ( k , n ) threshold scheme, divides secret datainto n separate shares in such a way that knowledge of at least any k of these n sharesmay be used to reconstruct the secret; using any fewer than k pieces will not allow thereconstruction. The shares are distributed to n distinct parties. Share exchanges amongparties for the reconstruction of the secret data may be carried out over insecure publicchannels. To build covert channels for share passing, steganographic methods with theLSB ( least significant bit ) replacement are commonly used. But stego objects generatedfrom these embedding methods may be easily detected by existing advanced steganalyticmethods. We consider synthetic steganography for the purpose of secretly exchangingshares. The basic idea of synthetic steganography is to construct/define stego objectsusing secret information which is quite different from embedding-based steganography.As an example of synthetic steganography, a steganographic tiling system is shown whichis based on a context-sensitive grammar.

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