12 research outputs found
Using Transcoding for Hidden Communication in IP Telephony
The paper presents a new steganographic method for IP telephony called
TranSteg (Transcoding Steganography). Typically, in steganographic
communication it is advised for covert data to be compressed in order to limit
its size. In TranSteg it is the overt data that is compressed to make space for
the steganogram. The main innovation of TranSteg is to, for a chosen voice
stream, find a codec that will result in a similar voice quality but smaller
voice payload size than the originally selected. Then, the voice stream is
transcoded. At this step the original voice payload size is intentionally
unaltered and the change of the codec is not indicated. Instead, after placing
the transcoded voice payload, the remaining free space is filled with hidden
data. TranSteg proof of concept implementation was designed and developed. The
obtained experimental results are enclosed in this paper. They prove that the
proposed method is feasible and offers a high steganographic bandwidth.
TranSteg detection is difficult to perform when performing inspection in a
single network localisation.Comment: 17 pages, 16 figures, 4 table
The channel for hidden data transmission in WSN
This paper describes an idea and realisation of hidden data transmision using Tiny Aggregation Covert Channel (TAGCC)in Wireless Sensor Networks. Our solution uses data aggregation mechanism called Tiny Aggregation (TAG). The protocol is based on idea of hidden messages sending without generate additional data packets and encryption. The paper describes details of proposed algorithm and simulation results obtained during testing of the sensor networks with hidden channel TAGCC
Covert Voice over Internet Protocol communications based on spatial model
This paper presents a new spatial steganography model for covert communications over Voice over Internet Protocol (VoIP), providing a solution to the issue of increasing the capacity of covert VoIP channels without compromising the imperceptibility of the channels. Drawing from Orthogonal Modulation Theory in communications, the model introduced two concepts, orthogonal data hiding features and data hiding vectors, to covert VoIP communications. By taking into account the variation characteristics of VoIP audio streams in the time domain, a hiding vector negotiation mechanism was suggested to achieve dynamic self-adaptive ste-ganography in media streams. Experimental results on VoIP steganography show that the pro-posed steganographic method effectively depicted the spatial and temporal characteristics of VoIP audio streams, and enhanced robustness against detection of steganalysis tools, thereby improving the security of covert VoIP communications
Audio steganografie a IP telefonie
Steganografia sa zaoberá skrývaním informácií. V tejto práci budeme tajné informácie ukrývať v paketoch posielaných počas hovoru Skype. Skype patrí k jed- ným z najznámejších a najpoužívanejších VoIP aplikácii. Navrhneme, popíšeme a implementujeme steganografickú metódu, pomocou ktorej budeme posielať tajnú správu počas hovoru Skype. Samotné vkladanie správy do paketov a ich extra- hovanie bude využívať steganografickú metódu maticového vkladania. Odolnosť tejto metódy voči strateným paketom zvýšime samoopravnými a samosynchro- nizačnými kódmi. Ako samoopravné kódy použijeme binárne Hammingove (7,4)- kódy a ako samosynchronizačné kódy poslúžia T-kódy. 1Steganography is a technique which hides secret information. In this work, we will hide a secret information in the packets which are produced during a Skype call. Skype is one of the best known and the most widely used VoIP applications. We will propose, describe and implement a steganography method by which we will send the secret message during the Skype call. For embedding the message into packets and extracting them, we will use steganographic method called matrix encoding. To avoid packet loss, we will increase the robustness of this method by error-correcting and self-synchronising codes. As error-correcting codes, we will use the binary Hamming (7, 4) -codes and for the self-synchronising, we will use T-codes. 1Department of AlgebraKatedra algebryMatematicko-fyzikální fakultaFaculty of Mathematics and Physic