Covert channels generated by tags in datagrams

The covert channels generated by tags are defined by separation in a data stream of sections which lengths are the codes of hidden transmitted data. Separation of sections of data is carried out with the help of tags. It is simpler to hide tags from detection, or it is possible to transfer them on other channel. In the paper, such covert channels are described by a couple of synchronized processes. The considered method of the hidden transmission allows to transfer large amount of hidden information in case of minor changes in a legal data stream. Examples of such covert channels are given. The correctness of coding and decoding of hidden information in such channels is proved. Such covert channels can be used not only for hidden information transfer, but also for integrity monitoring. Methods of creation of proved invisible tags for such channels are found. Invisibility is provided with cryptography methods. Implementation ability of the considered methods is confirmed experimentally. The computer prototype for experiments uses only the open software.