As the VoIP steganographic methods provide a low capacity covert channel for data transmission, an efficient and real-time data transmission protocol over this channel is required which provides reliability with minimum bandwidth usage. This paper proposes a micro-protocol for data embedding over covert storage channels or covert hybrid channels developed by steganographic methods where real-time transport protocol (RTP) is their underlying protocol. This micro-protocol applies an improved Go-Back-N mechanism which exploits some RTP header fields and error correction codes to retain maximum covert channel capacity while providing reliability. The bandwidth usage and the performance of the proposed micro-protocol are analyzed. The analyses indicate that the performance depends on the network conditions, the underlying steganographic method, the error correction code and the adjustable parameters of the micro-protocol. Therefore, a genetic algorithm is devised to obtain the optimal values of the adjustable micro-protocol parameters. The impact of network conditions, the underlying steganographic method and the error correction code on the performance are assessed through simulations. The performance of this micro-protocol is compared to an existing method named ReLACK where this micro-protocol outperforms its counterpart.

中文翻译：

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一种可靠高效的微协议，用于通过基于 RTP 的隐蔽通道进行数据传输

由于 VoIP 隐写方法为数据传输提供了一个低容量的隐蔽通道，因此需要通过该通道的高效和实时数据传输协议，以最小的带宽使用提供可靠性。本文提出了一种微协议，用于通过隐写方法开发的隐式存储通道或隐式混合通道上的数据嵌入，其中实时传输协议 (RTP) 是其底层协议。该微协议应用了改进的 Go-Back-N 机制，该机制利用一些 RTP 报头字段和纠错码来保持最大的隐蔽信道容量，同时提供可靠性。分析了所提出的微协议的带宽使用和性能。分析表明，性能取决于网络条件、底层隐写方法、微协议的纠错码和可调参数。因此，设计了遗传算法来获得可调微协议参数的最优值。通过模拟评估网络条件、底层隐写方法和纠错码对性能的影响。将此微协议的性能与名为 ReLACK 的现有方法进行比较，其中该微协议的性能优于其对应物。