A Robust and Flexible Covert Channel in LTE-A System

LTE-A (Long Term Evolution-Advanced) is a 3GPP standard which is an advancement to Long Term Evolution (LTE) and a predecessor of 4G. The rapid development of LTE-A, with a growing base of users, makes it a potential and promising target for covert channels. In this paper, we propose a novel covert channel, called LaSPsteg, designed for LTE-A systems. This method leverages the SN (Sequence Number) field in the header of PDU (Packet Data Unit) to choose covert packets. Then the padding bits in the payload of PDU of chosen packets are used to carry secret information. Specifically, we utilize a pre-shared hash function and an independent variable parameter to achieve varying embedding rules thus ensure the flexibility of our proposed covert channel.