The existing ways of classification of steganography methods, processing and their systematization were analysed. In addition to well-known methods of steganographic protection, as a separate section of steganography can be defined network steganography, whereas the secret data carriers, use network protocols OSI, were determined. The optimal system of classification of all methods of steganography was created. Determined that the most current methods, for hiding messages in digital containers, are using the exponential dependence of reliability of system of the volume of embedded data. This dependence shows that by increasing the volume of embedded data decrease the reliability of the system (at constant size of the container). Thus, used in stegosystem container imposes restrictions on the size of the embedded data.