  Network steganography encompasses the information hiding techniques that can
be applied in communication network environments and that utilize hidden data
carriers for this purpose. In this paper we introduce a characteristic called
steganographic cost which is an indicator for the degradation or distortion of
the carrier caused by the application of the steganographic method. Based on
exemplary cases for single- and multi-method steganographic cost analyses we
observe that it can be an important characteristic that allows to express
hidden data carrier degradation - similarly as MSE (Mean-Square Error) or PSNR
(Peak Signal-to-Noise Ratio) are utilized for digital media steganography.
Steganographic cost can moreover be helpful to analyse the relationships
between two or more steganographic methods applied to the same hidden data
carrier.
