RSTEG in TCP Protocol: A Novel Approach in Information Hiding
P. Karthika, P. Hemalatha, V. Sujitha · 2024
Steganography is a method that has been used for years to communicate information in secret. These covert communications are placed into truthful carriers. Digital photos, music files, video data, and so on may all be carriers. The study introduces RSTEG (Retransmission STEGanography), a novel stenographic technique meant for a wide range of protocols that make use of rebroadcast techniques. RSTEG’s primary novelty is its deliberate use of retransmission to force a packet to be acknowledged even after it has been completely acknowledged. The payload field of the transmitted packet contains a steganogram rather than user data. We examine the properties of RSTEG in this study. As part of the recipient’s covert communication strategy, a selected segment’s payload has an Identifying Sequence (IS) strategically inserted within it. After delivery is successful, the recipient does not send back an acknowledgment (ACK). The sending phase includes queuing steganograms from the application layer, and upon cover data arrival, an IS is inserted for retransmission identification. In the receiving phase, the receiver identifies IS-containing segments, withholding ACK for RSTEG requests and acknowledging non-RSTEG data. The crucial retransmission phase involves creating counters for marked segments; if triggered, retransmission occurs with a steganogram in place or unchanged payload based on the counter status. The experimentation involves a client/server architecture with a basic TCP implementation relying on Retransmission Time Outs (RTO), incorporating the functionalities of RSTEG and by implementing the compensating algorithm to increase the stealthiness of RSTEG.