Influence of speech codecs selection on transcoding steganography

Janicki, Artur; Mazurczyk, Wojciech; Szczypiorski, Krzysztof

doi:10.1007/s11235-014-9937-9

Cited by 13 publications

(12 citation statements)

References 32 publications

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“…As already mentioned, TranSteg performance depends strongly on the selection of the overt and covert codecs. This problem was discussed in detail in , where we experimentally measured steganographic bandwidth, that is, the difference between bitrates of the overt and covert codecs, and steganographic cost, that is, the decrease in quality caused by transcoding, for various pairs of speech codecs. We examined the overt codecs most commonly encountered in IP telephony: G.711, Speex, iLBC, and G.723.1.…”

Section: Resultsmentioning

confidence: 99%

“…In , the most popular codecs for IP telephony were evaluated to establish which pairs of codecs should be chosen for transcoding to minimize the negative influence on the hidden data carriers while maximizing the obtained steganographic bandwidth. From this analysis, it was determined that the choice of covert codec depends on whether priority is given to higher steganographic bandwidth or better speech quality.…”

Section: Introductionmentioning

confidence: 99%

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On the undetectability of transcoding steganography

Janicki

Mazurczyk

Szczypiorski

2015

Security Comm Networks

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Transcoding Steganography (TranSteg) is a fairly new IP telephony steganographic method that is characterized by a high steganographic bandwidth, low introduced distortions, and high undetectability. TranSteg utilizes compression of the overt data to free space for the secret data bits. In this paper, we focus on evaluating different possibilities for TranSteg detection. Building on the previous works, we perform a wide analysis of different steganalysis methods to assess the possibility of TranSteg detection and identify the most 'undetectable' pairs of voice codecs.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

On the undetectability of transcoding steganography

Janicki

Mazurczyk

Szczypiorski

2015

Security Comm Networks

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“…The saved bits were used to carry a steganogram. Results of experiments for various pairs of overt/covert codecs, presented in , showed the high effectiveness of this method. The authors were able to create hidden channels with capacities of over 30 kbps at a quality decrease of between 0 and 1 MOS.…”

Section: Steganography In Voice Over Ip Systemsmentioning

confidence: 87%

“…For speech quality assessment, we used the perceptual evaluation of speech quality (PESQ) algorithm , which is an algorithm that was used previously in numerous studies on steganography, for example, in and . To estimate speech quality, PESQ required both the speech signal being tested and the original one.…”

Section: Experimental Set‐upmentioning

confidence: 99%

Pitch‐based steganography for Speex voice codec

Janicki

2016

Security Comm Networks

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This paper presents an improved version of a steganographic algorithm for IP telephony called HideF0. It is based on approximating the F0 parameter, which is responsible for conveying information about the pitch of the speech signal. The bits saved due to simplification of the pitch contour are used for the hidden transmission. In our experiments, the proposed method was applied to the narrowband Speex codec working in five different modes, with bitrates between 5,950 bps and 24,600 bps. We showed that HideF0 was able to create hidden channels with steganographic bandwidths of around 200 bps at the expense of a steganographic cost of between 0.5 and 0.7 MOS, depending on the Speex mode. Because of placing the approximation flag in the voice packet header, the improved version of the proposed algorithm yielded a significantly lower decrease in speech quality, when compared with the original version of HideF0. In addition, for low bitrates of the hidden channel (i.e., below ca. 50 bps) it was able to operate without introducing any steganographic cost. Copyright © 2016 John Wiley & Sons, Ltd.

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“…The secret messages are then embedded into the saved spaces of RTP packets. The test results of a proof-of-concept implementation demonstrate that TranSteg can provide a steganographic bandwidth of 32 kbit/s while retaining good speech quality and introducing delays lower than 1 ms. Later, Janicki et al [35] extended this work by analyzing the influence of codec selection on TranSteg efficiency. Further, Janicki et al [36] presented a steganalysis method for TranSteg based on Gaussian mixture models and mel-frequency cepstral coefficients, which is efficient to detect codec pairs, such as G.711/G.726, Speex7/G.729 and Speex7/iLBC, but ineffective to detect other codec pairs, e.g., iLBC/AMR.…”

Section: Transcoding Steganography (Transteg)mentioning

confidence: 99%