New Covert Channels in Internet of Things

Network steganography is a relatively new discipline which studies different steganographic techniques that utilize network protocols for data hiding. Internet of Things (IoT) is a concept which integrates billions of embedded devices that communicate to each other. To the best of our knowledge, there are not many attempts that utilize existing network steganographic techniques in protocols specifically created for IoT. Therefore, in this paper, we present several new covert channels that utilize the Constrained Application Protocol (CoAP), which is a specialized Web transfer protocol used for constrained devices and networks. This protocol can be used regardless of its transport carrier (Datagram Transport Layer Security - DTLS or clear UDP – User Datagram Protocol). The suggested covert channels are categorized according to the pattern-based classification, and, for each covert channel, the total number of hidden data bits transmitted per CoAP message or its Packet Raw Bit Rate (PRBP) is given