Image Hiding on Audio Subband Based On Centroid in Frequency Domain

ABSTRAK Audio watermarking adalah mekanisme penyembunyian data pada audio. Metode penyembunyian data yang digunakan dalam penulisan ini adalah Lifting Wavelet Transform (LWT), Fast Fourier Transform (FFT), Centroid dan Quantization Index Modulation (QIM). Langkah pertama adalah host audio tersegmentasi menjadi beberapa frame. Kemudian sub-band terpilih diubah oleh FFT dengan mengubah domain sub-band dari waktu ke frekuensi. Proses centroid digunakan untuk menemukan titik pusat frekuensi untuk lokasi penyisipan untuk mendapatkan output yang lebih stabil. Proses penyematan dilakukan dengan QIM. Kinerja watermarking oleh parameter yang disesuaikan memperoleh nilai imperceptibility dengan Signal to Noise Ratio (SNR) > 21 dB, Mean Opinion Score (MOS)> 3.8 dengan kapasitas = 86.13 bps. Selain itu, untuk sebagian besar file audio terwatermark yang diserang, metode ini tahan terhadap beberapa serangan seperti Low Pass Filter (LPF) dengan fco> 6 kHz, Band Pass Filter (BPF) dengan fco 50 Hz - 6 kHz, Linear Speed Change (LSC) dan MP4 Compression dengan Bit Error Rate (BER) kurang dari 20%. Kata kunci: FFT, subband, LWT, Centroid, Audio Watermarking, QIM   ABSTRACT Audio watermarking is a mechanism for hiding data on audio. Data hiding methods used in this paper are Lifting Wavelet Transform (LWT), Fast Fourier Transform (FFT), Centroid and Quantization Index Modulation (QIM). The first step is to segment host audio into several frames, then the selected sub-band is changed by the FFT by changing the sub-band domain from time to frequency. The centroid process is used to find the center of frequency for the insertion location to get a more stable output. The embedding process is done by QIM. The watermarking performance by adjusted parameters obtains the imperceptibility value with Signal to Noise Ratio (SNR)> 21 dB, Mean Opinion Score (MOS)> 3.8 with a capacity = 86.13 bps. In addition, for most of attacked watermarked audio files, this method is resistant to several attacks such as Low Pass Filter (LPF) with fco> 6 kHz, Band Pass Filter (BPF) with fco 50 Hz - 6 kHz, Linear Speed Change (LSC) and MP4 Compression with Bit Error Rate (BER) less than 20%. Keywords: FFT, subband, LWT, Centroid, Audio Watermarking, QI

Digital Watermarking for Verification of Perception-based Integrity of Audio Data

In certain application fields digital audio recordings contain sensitive content. Examples are historical archival material in public archives that preserve our cultural heritage, or digital evidence in the context of law enforcement and civil proceedings. Because of the powerful capabilities of modern editing tools for multimedia such material is vulnerable to doctoring of the content and forgery of its origin with malicious intent. Also inadvertent data modification and mistaken origin can be caused by human error. Hence, the credibility and provenience in terms of an unadulterated and genuine state of such audio content and the confidence about its origin are critical factors. To address this issue, this PhD thesis proposes a mechanism for verifying the integrity and authenticity of digital sound recordings. It is designed and implemented to be insensitive to common post-processing operations of the audio data that influence the subjective acoustic perception only marginally (if at all). Examples of such operations include lossy compression that maintains a high sound quality of the audio media, or lossless format conversions. It is the objective to avoid de facto false alarms that would be expectedly observable in standard crypto-based authentication protocols in the presence of these legitimate post-processing. For achieving this, a feasible combination of the techniques of digital watermarking and audio-specific hashing is investigated. At first, a suitable secret-key dependent audio hashing algorithm is developed. It incorporates and enhances so-called audio fingerprinting technology from the state of the art in contentbased audio identification. The presented algorithm (denoted as ”rMAC” message authentication code) allows ”perception-based” verification of integrity. This means classifying integrity breaches as such not before they become audible. As another objective, this rMAC is embedded and stored silently inside the audio media by means of audio watermarking technology. This approach allows maintaining the authentication code across the above-mentioned admissible post-processing operations and making it available for integrity verification at a later date. For this, an existent secret-key ependent audio watermarking algorithm is used and enhanced in this thesis work. To some extent, the dependency of the rMAC and of the watermarking processing from a secret key also allows authenticating the origin of a protected audio. To elaborate on this security aspect, this work also estimates the brute-force efforts of an adversary attacking this combined rMAC-watermarking approach. The experimental results show that the proposed method provides a good distinction and classification performance of authentic versus doctored audio content. It also allows the temporal localization of audible data modification within a protected audio file. The experimental evaluation finally provides recommendations about technical configuration settings of the combined watermarking-hashing approach. Beyond the main topic of perception-based data integrity and data authenticity for audio, this PhD work provides new general findings in the fields of audio fingerprinting and digital watermarking. The main contributions of this PhD were published and presented mainly at conferences about multimedia security. These publications were cited by a number of other authors and hence had some impact on their works

A multi-level perspective analysis of the change in music consumption 1989-2014

This thesis seeks to examine the historical socio-technical transitions in the music industry through the 1990s and 2000s which fundamentally altered the way in which music is consumed along with the environmental resource impact of such transitions. Specifically, the investigation seeks to establish a historical narrative of events that are significant to the story of this transition through the use of the multi-level perspective on socio-technical transitions as a framework. This thesis adopts a multi-level perspective for socio-technical transitions approach to analyse this historical narrative seeking to identify key events and actors that influenced the transition as well as enhance the methodological implementation of the multi-level perspective. Additionally, this thesis utilised the Material Intensity Per Service unit methodology to derive several illustrative scenarios of music consumption and their associated resource usage to establish whether the socio-technical transitions experienced by the music industry can be said to be dematerialising socio-technical transitions. This thesis provides a number of original empirical and theoretical contributions to knowledge. This is achieved by presenting a multi-level perspective analysis of a historical narrative established using over 1000 primary sources. The research identifies, examines and discusses key events, actors and transition pathways denote the complex nature of dematerialising socio-technical systems as well as highlights specifically the influence different actors and actor groups can have on the pathways that transitions take. The thesis also provides a broader contribution to the understanding of dematerialisation and technology convergence

Capacity-optimized mp2 audio watermarking

Today a number of audio watermarking algorithms have been proposed, some of them at a quality making them suitable for commercial applications. The focus of most of these algorithms is copyright protection. Therefore, transparency and robustness are the most discussed and optimised parameters. But other applications for audio watermarking can also be identified stressing other parameters like complexity or payload. In our paper, we introduce a new mp2 audio watermarking algorithm optimised for high payload. Our algorithm uses the scale factors of an mp2 file for watermark embedding. They are grouped and masked based on a pseudo-random pattern generated from a secret key. In each group, we embed one bit. Depending on the bit to embed, we change the scale factors by adding 1 where necessary until it includes either more even or uneven scale factors. An uneven group has a 1 embedded, an even group a 0. The same rule is later applied to detect the watermark. The group size can be increased or decreased for transparency/payload trade-off. We embed 160 bits or more in an mp2 file per second without reducing perceived quality. As an application example, we introduce a prototypic Karaoke system displaying song lyrics embedded as a watermark