607 research outputs found
Sensor Data Integrity Verification for Real-time and Resource Constrained Systems
Sensors are used in multiple applications that touch our lives and have become an integral part of modern life. They are used in building intelligent control systems in various industries like healthcare, transportation, consumer electronics, military, etc. Many mission-critical applications require sensor data to be secure and authentic. Sensor data security can be achieved using traditional solutions like cryptography and digital signatures, but these techniques are computationally intensive and cannot be easily applied to resource constrained systems. Low complexity data hiding techniques, on the contrary, are easy to implement and do not need substantial processing power or memory. In this applied research, we use and configure the established low complexity data hiding techniques from the multimedia forensics domain. These techniques are used to secure the sensor data transmissions in resource constrained and real-time environments such as an autonomous vehicle. We identify the areas in an autonomous vehicle that require sensor data integrity and propose suitable water-marking techniques to verify the integrity of the data and evaluate the performance of the proposed method against different attack vectors. In our proposed method, sensor data is embedded with application specific metadata and this process introduces some distortion. We analyze this embedding induced distortion and its impact on the overall sensor data quality to conclude that watermarking techniques, when properly configured, can solve sensor data integrity verification problems in an autonomous vehicle.Ph.D.College of Engineering & Computer ScienceUniversity of Michigan-Dearbornhttp://deepblue.lib.umich.edu/bitstream/2027.42/167387/3/Raghavendar Changalvala Final Dissertation.pdfDescription of Raghavendar Changalvala Final Dissertation.pdf : Dissertatio
Authoritative and Unbiased Responses to Geographic Queries
Trust in information systems stem from two key properties of responses to queries regarding the state of the system, viz., i) authoritativeness, and ii) unbiasedness. That the response is authoritative implies that i) the provider (source) of the response, and ii) the chain of delegations through which the provider obtained the authority to respond, can be verified. The property of unbiasedness implies that no system data relevant to the query is deliberately or accidentally suppressed. The need for guaranteeing these two important properties stem from the impracticality for the verifier to exhaustively verify the correctness of every system process, and the integrity of the platform on which system processes are executed. For instance, the integrity of a process may be jeopardized by i) bugs (attacks) in computing hardware like Random Access Memory (RAM), input/output channels (I/O), and Central Processing Unit( CPU), ii) exploitable defects in an operating system, iii) logical bugs in program implementation, and iv) a wide range of other embedded malfunctions, among others. A first step in ensuing AU properties of geographic queries is the need to ensure AU responses to a specific type of geographic query, viz., point-location. The focus of this dissertation is on strategies to leverage assured point-location, for i) ensuring authoritativeness and unbiasedness (AU) of responses to a wide range of geographic queries; and ii) useful applications like Secure Queryable Dynamic Maps (SQDM) and trustworthy redistricting protocol. The specific strategies used for guaranteeing AU properties of geographic services include i) use of novel Merkle-hash tree- based data structures, and ii) blockchain networks to guarantee the integrity of the processes
A Framework for Facilitating Secure Design and Development of IoT Systems
The term Internet of Things (IoT) describes an ever-growing ecosystem of physical objects
or things interconnected with each other and connected to the Internet. IoT devices
consist of a wide range of highly heterogeneous inanimate and animate objects. Thus, a
thing in the context of the IoT can even mean a person with blood pressure or heart rate
monitor implant or a pet with a biochip transponder. IoT devices range from ordinary
household appliances, such as smart light bulbs or smart coffee makers, to sophisticated
tools for industrial automation. IoT is currently leading a revolutionary change in many
industries and, as a result, a lot of industries and organizations are adopting the paradigm
to gain a competitive edge. This allows them to boost operational efficiency and optimize
system performance through real-time data management, which results in an optimized
balance between energy usage and throughput. Another important application area is
the Industrial Internet of Things (IIoT), which is the application of the IoT in industrial
settings. This is also referred to as the Industrial Internet or Industry 4.0, where Cyber-
Physical Systems (CPS) are interconnected using various technologies to achieve wireless
control as well as advanced manufacturing and factory automation. IoT applications
are becoming increasingly prevalent across many application domains, including smart
healthcare, smart cities, smart grids, smart farming, and smart supply chain management.
Similarly, IoT is currently transforming the way people live and work, and hence
the demand for smart consumer products among people is also increasing steadily. Thus,
many big industry giants, as well as startup companies, are competing to dominate the
market with their new IoT products and services, and hence unlocking the business value
of IoT.
Despite its increasing popularity, potential benefits, and proven capabilities, IoT is still in
its infancy and fraught with challenges. The technology is faced with many challenges, including
connectivity issues, compatibility/interoperability between devices and systems,
lack of standardization, management of the huge amounts of data, and lack of tools for
forensic investigations. However, the state of insecurity and privacy concerns in the IoT
are arguably among the key factors restraining the universal adoption of the technology.
Consequently, many recent research studies reveal that there are security and privacy issues
associated with the design and implementation of several IoT devices and Smart Applications
(smart apps). This can be attributed, partly, to the fact that as some IoT device
makers and smart apps development companies (especially the start-ups) reap business
value from the huge IoT market, they tend to neglect the importance of security. As a
result, many IoT devices and smart apps are created with security vulnerabilities, which
have resulted in many IoT related security breaches in recent years.
This thesis is focused on addressing the security and privacy challenges that were briefly
highlighted in the previous paragraph. Given that the Internet is not a secure environ ment even for the traditional computer systems makes IoT systems even less secure due
to the inherent constraints associated with many IoT devices. These constraints, which are
mainly imposed by cost since many IoT edge devices are expected to be inexpensive and
disposable, include limited energy resources, limited computational and storage capabilities,
as well as lossy networks due to the much lower hardware performance compared
to conventional computers. While there are many security and privacy issues in the IoT
today, arguably a root cause of such issues is that many start-up IoT device manufacturers
and smart apps development companies do not adhere to the concept of security by
design. Consequently, some of these companies produce IoT devices and smart apps with
security vulnerabilities.
In recent years, attackers have exploited different security vulnerabilities in IoT infrastructures
which have caused several data breaches and other security and privacy incidents
involving IoT devices and smart apps. These have attracted significant attention
from the research community in both academia and industry, resulting in a surge of proposals
put forward by many researchers. Although research approaches and findings may
vary across different research studies, the consensus is that a fundamental prerequisite for
addressing IoT security and privacy challenges is to build security and privacy protection
into IoT devices and smart apps from the very beginning. To this end, this thesis investigates
how to bake security and privacy into IoT systems from the onset, and as its main
objective, this thesis particularly focuses on providing a solution that can foster the design
and development of secure IoT devices and smart apps, namely the IoT Hardware Platform
Security Advisor (IoT-HarPSecA) framework. The security framework is expected to
provide support to designers and developers in IoT start-up companies during the design
and implementation of IoT systems. IoT-HarPSecA framework is also expected to facilitate
the implementation of security in existing IoT systems.
To accomplish the previously mentioned objective as well as to affirm the aforementioned
assertion, the following step-by-step problem-solving approach is followed. The first step
is an exhaustive survey of different aspects of IoT security and privacy, including security requirements in IoT architecture, security threats in IoT architecture, IoT application domains
and their associated cyber assets, the complexity of IoT vulnerabilities, and some
possible IoT security and privacy countermeasures; and the survey wraps up with a brief
overview of IoT hardware development platforms. The next steps are the identification of
many challenges and issues associated with the IoT, which narrowed down to the abovementioned
fundamental security/privacy issue; followed by a study of different aspects of
security implementation in the IoT. The remaining steps are the framework design thinking
process, framework design and implementation, and finally, framework performance
evaluation.
IoT-HarPSecA offers three functionality features, namely security requirement elicitation security best practice guidelines for secure development, and above all, a feature that recommends
specific Lightweight Cryptographic Algorithms (LWCAs) for both software and
hardware implementations. Accordingly, IoT-HarPSecA is composed of three main components,
namely Security Requirements Elicitation (SRE) component, Security Best Practice
Guidelines (SBPG) component, and Lightweight Cryptographic Algorithms Recommendation
(LWCAR) component, each of them servicing one of the aforementioned features.
The author has implemented a command-line tool in C++ to serve as an interface
between users and the security framework. This thesis presents a detailed description,
design, and implementation of the SRE, SBPG, and LWCAR components of the security
framework. It also presents real-world practical scenarios that show how IoT-HarPSecA
can be used to elicit security requirements, generate security best practices, and recommend
appropriate LWCAs based on user inputs. Furthermore, the thesis presents performance
evaluation of the SRE, SBPG, and LWCAR components framework tools, which
shows that IoT-HarPSecA can serve as a roadmap for secure IoT development.O termo Internet das coisas (IoT) é utilizado para descrever um ecossistema, em expansão,
de objetos fÃsicos ou elementos interconetados entre si e à Internet. Os dispositivos
IoT consistem numa gama vasta e heterogénea de objetos animados ou inanimados e,
neste contexto, podem pertencer à IoT um indivÃduo com um implante que monitoriza a
frequência cardÃaca ou até mesmo um animal de estimação que tenha um biochip. Estes
dispositivos variam entre eletrodomésticos, tais como máquinas de café ou lâmpadas inteligentes,
a ferramentas sofisticadas de uso na automatização industrial. A IoT está a
revolucionar e a provocar mudanças em várias indústrias e muitas adotam esta tecnologia
para incrementar as suas vantagens competitivas. Este paradigma melhora a eficiência
operacional e otimiza o desempenho de sistemas através da gestão de dados em tempo
real, resultando num balanço otimizado entre o uso energético e a taxa de transferência.
Outra área de aplicação é a IoT Industrial (IIoT) ou internet industrial ou Indústria 4.0,
ou seja, uma aplicação de IoT no âmbito industrial, onde os sistemas ciberfÃsicos estão interconectados
a diversas tecnologias de forma a obter um controlo de rede sem fios, bem
como fabricações avançadas e automatização fabril. As aplicações da IoT estão a crescer
e a tornarem-se predominantes em muitos domÃnios de aplicação inteligentes como sistemas
de saúde, cidades, redes, agricultura e sistemas de fornecimento. Da mesma forma,
a IoT está a transformar estilos de vida e de trabalho e assim, a procura por produtos inteligentes
está constantemente a aumentar. As grandes indústrias e startups competem
entre si de forma a dominar o mercado com os seus novos serviços e produtos IoT, desbloqueando
o valor de negócio da IoT.
Apesar da sua crescente popularidade, benefÃcios e capacidades comprovadas, a IoT está
ainda a dar os seus primeiros passos e é confrontada com muitos desafios. Entre eles,
problemas de conectividade, compatibilidade/interoperabilidade entre dispositivos e sistemas,
falta de padronização, gestão das enormes quantidades de dados e ainda falta de
ferramentas para investigações forenses. No entanto, preocupações quanto ao estado de
segurança e privacidade ainda estão entre os fatores adversos à adesão universal desta
tecnologia. Estudos recentes revelaram que existem questões de segurança e privacidade
associadas ao design e implementação de vários dispositivos IoT e aplicações inteligentes
(smart apps.), isto pode ser devido ao facto, em parte, de que alguns fabricantes e empresas
de desenvolvimento de dispositivos (especialmente startups) IoT e smart apps., recolham
o valor de negócio dos grandes mercados IoT, negligenciando assim a importância
da segurança, resultando em dispositivos IoT e smart apps. com carências e violações de
segurança da IoT nos últimos anos.
Esta tese aborda os desafios de segurança e privacidade que foram supra mencionados.
Visto que a Internet e os sistemas informáticos tradicionais são por vezes considerados inseguros,
os sistemas IoT tornam-se ainda mais inseguros, devido a restrições inerentes a tais dispositivos. Estas restrições são impostas devido ao custo, uma vez que se espera que
muitos dispositivos de ponta sejam de baixo custo e descartáveis, com recursos energéticos
limitados, bem como limitações na capacidade de armazenamento e computacionais,
e redes com perdas devido a um desempenho de hardware de qualidade inferior, quando
comparados com computadores convencionais. Uma das raÃzes do problema é o facto
de que muitos fabricantes, startups e empresas de desenvolvimento destes dispositivos e
smart apps não adiram ao conceito de segurança por construção, ou seja, logo na conceção,
não preveem a proteção da privacidade e segurança. Assim, alguns dos produtos e
dispositivos produzidos apresentam vulnerabilidades na segurança.
Nos últimos anos, hackers maliciosos têm explorado diferentes vulnerabilidades de segurança
nas infraestruturas da IoT, causando violações de dados e outros incidentes de
privacidade envolvendo dispositivos IoT e smart apps. Estes têm atraÃdo uma atenção significativa
por parte das comunidades académica e industrial, que culminaram num grande
número de propostas apresentadas por investigadores cientÃficos. Ainda que as abordagens
de pesquisa e os resultados variem entre os diferentes estudos, há um consenso e
pré-requisito fundamental para enfrentar os desafios de privacidade e segurança da IoT,
que buscam construir proteção de segurança e privacidade em dispositivos IoT e smart
apps. desde o fabrico. Para esta finalidade, esta tese investiga como produzir segurança
e privacidade destes sistemas desde a produção, e como principal objetivo, concentra-se
em fornecer soluções que possam promover a conceção e o desenvolvimento de dispositivos
IoT e smart apps., nomeadamente um conjunto de ferramentas chamado Consultor
de Segurança da Plataforma de Hardware da IoT (IoT-HarPSecA). Espera-se que o conjunto
de ferramentas forneça apoio a designers e programadores em startups durante a
conceção e implementação destes sistemas ou que facilite a integração de mecanismos de
segurança nos sistemas préexistentes.
De modo a alcançar o objetivo proposto, recorre-se à seguinte abordagem. A primeira fase
consiste num levantamento exaustivo de diferentes aspetos da segurança e privacidade na
IoT, incluindo requisitos de segurança na arquitetura da IoT e ameaças à sua segurança,
os seus domÃnios de aplicação e os ativos cibernéticos associados, a complexidade das
vulnerabilidades da IoT e ainda possÃveis contramedidas relacionadas com a segurança e
privacidade. Evolui-se para uma breve visão geral das plataformas de desenvolvimento
de hardware da IoT. As fases seguintes consistem na identificação dos desafios e questões
associadas à IoT, que foram restringidos às questões de segurança e privacidade. As demais
etapas abordam o processo de pensamento de conceção (design thinking), design e
implementação e, finalmente, a avaliação do desempenho.
O IoT-HarPSecA é composto por três componentes principais: a Obtenção de Requisitos
de Segurança (SRE), Orientações de Melhores Práticas de Segurança (SBPG) e a recomendação
de Componentes de Algoritmos Criptográficos Leves (LWCAR) na implementação de software e hardware. O autor implementou uma ferramenta em linha de comandos
usando linguagem C++ que serve como interface entre os utilizadores e a IoT-HarPSecA.
Esta tese apresenta ainda uma descrição detalhada, desenho e implementação das componentes
SRE, SBPG, e LWCAR. Apresenta ainda cenários práticos do mundo real que
demostram como o IoT-HarPSecA pode ser utilizado para elicitar requisitos de segurança,
gerar boas práticas de segurança (em termos de recomendações de implementação) e recomendar
algoritmos criptográficos leves apropriados com base no contributo dos utilizadores.
De igual forma, apresenta-se a avaliação do desempenho destes três componentes,
demonstrando que o IoT-HarPSecA pode servir como um roteiro para o desenvolvimento
seguro da IoT
Optimisation of Tamper Localisation and Recovery Watermarking Techniques
Digital watermarking has found many applications in many fields, such as:
copyright tracking, media authentication, tamper localisation and recovery,
hardware control, and data hiding. The idea of digital watermarking is to embed
arbitrary data inside a multimedia cover without affecting the perceptibility of the
multimedia cover itself. The main advantage of using digital watermarking over
other techniques, such as signature based techniques, is that the watermark is
embedded into the multimedia cover itself and will not be removed even with the
format change.
Image watermarking techniques are categorised according to their robustness
against modification into: fragile, semi-fragile, and robust watermarking. In fragile
watermarking any change to the image will affect the watermark, this makes fragile
watermarking very useful in image authentication applications, as in medical and
forensic fields, where any tampering of the image is: detected, localised, and
possibly recovered. Fragile watermarking techniques are also characterised by a
higher capacity when compared to semi-fragile and robust watermarking. Semifragile
watermarking techniques resist some modifications, such as lossy
compression and low pass filtering. Semi-fragile watermarking can be used in
authentication and copyright validation applications whenever the amount of
embedded information is small and the expected modifications are not severe.
Robust watermarking techniques are supposed to withstand more severe
modifications, such as rotation and geometrical bending. Robust watermarking is
used in copyright validation applications, where copyright information in the image
must remains accessible even after severe modification.
This research focuses on the application of image watermarking in tamper
localisation and recovery and it aims to provide optimisation for some of its
aspects. The optimisation aims to produce watermarking techniques that enhance
one or more of the following aspects: consuming less payload, having better
recovery quality, recovering larger tampered area, requiring less calculations, and
being robust against the different counterfeiting attacks. Through the survey of the main existing techniques, it was found that most of them
are using two separate sets of data for the localisation and the recovery of the
tampered area, which is considered as a redundancy. The main focus in this
research is to investigate employing image filtering techniques in order to use only
one set of data for both purposes, leading to a reduced redundancy in the
watermark embedding and enhanced capacity. Four tamper localisation and
recovery techniques were proposed, three of them use one set of data for
localisation and recovery while the fourth one is designed to be optimised and
gives a better performance even though it uses separate sets of data for
localisation and recovery.
The four techniques were analysed and compared to two recent techniques in the
literature. The performance of the proposed techniques vary from one technique to
another. The fourth technique shows the best results regarding recovery quality
and Probability of False Acceptance (PFA) when compared to the other proposed
techniques and the two techniques in the literature, also, all proposed techniques
show better recovery quality when compared to the two techniques in the
literature
Erasable PUFs: Formal treatment and generic design
Physical Unclonable Functions (PUFs) have not only been suggested as new key storage mechanism, but - in the form of so-called "Strong PUFs"- also as cryptographic primitives in advanced schemes, including key exchange, oblivious transfer, or secure multi-party computation. This notably extends their application spectrum, and has led to a sequence of publications at leading venues such as IEEE S&P, CRYPTO, and EUROCRYPT in the past[3,6,10,11,29, 41]. However, one important unresolved problem is that adversaries can break the security of all these advanced protocols if they gain physical access to the employed Strong PUFs after protocol completion [41]. It has been formally proven[49] that this issue cannot be overcome by techniques on the protocol side alone, but requires resolution on the hardware level - the only fully effective known countermeasure being so-called Erasable PUFs. Building on this work, this paper is the first to describe a generic method how any given silicon Strong PUF with digital CRP-interface can be turned into an Erasable PUFs[36]. We describe how the Strong PUF can be surrounded with a trusted control logic that allows the blocking (or "erasure") of single CRPs. We implement our approach, which we call "GeniePUF", on FPGA, reporting detailed performance data and practicality figures. Furthermore, we develop the first comprehensive definitional framework for Erasable PUFs. Our work so re-establishes the effective usability of Strong PUFs in advanced cryptographic applications, and in the realistic case adversaries get access to the Strong PUF after protocol completion
Machine learning and blockchain technologies for cybersecurity in connected vehicles
Future connected and autonomous vehicles (CAVs) must be secured againstcyberattacks for their everyday functions on the road so that safety of passengersand vehicles can be ensured. This article presents a holistic review of cybersecurityattacks on sensors and threats regardingmulti-modal sensor fusion. A compre-hensive review of cyberattacks on intra-vehicle and inter-vehicle communicationsis presented afterward. Besides the analysis of conventional cybersecurity threatsand countermeasures for CAV systems,a detailed review of modern machinelearning, federated learning, and blockchain approach is also conducted to safe-guard CAVs. Machine learning and data mining-aided intrusion detection systemsand other countermeasures dealing with these challenges are elaborated at theend of the related section. In the last section, research challenges and future direc-tions are identified
Copyright protection of scalar and multimedia sensor network data using digital watermarking
This thesis records the research on watermarking techniques to address the issue of copyright protection of the scalar data in WSNs and image data in WMSNs, in order to ensure that the proprietary information remains safe between the sensor nodes in both. The first objective is to develop LKR watermarking technique for the copyright protection of scalar data in WSNs. The second objective is to develop GPKR watermarking technique for copyright protection of image data in WMSN
Applications de la représentation parcimonieuse perceptuelle par graphe de décharges (Spikegramme) pour la protection du droit d’auteur des signaux sonores
Chaque année, le piratage mondial de la musique coûte plusieurs milliards de dollars en
pertes économiques, pertes d’emplois et pertes de gains des travailleurs ainsi que la perte
de millions de dollars en recettes fiscales. La plupart du piratage de la musique est dû
à la croissance rapide et à la facilité des technologies actuelles pour la copie, le partage,
la manipulation et la distribution de données musicales [Domingo, 2015], [Siwek, 2007].
Le tatouage des signaux sonores a été proposé pour protéger les droit des auteurs et
pour permettre la localisation des instants où le signal sonore a été falsifié. Dans cette
thèse, nous proposons d’utiliser la représentation parcimonieuse bio-inspirée par graphe de
décharges (spikegramme), pour concevoir une nouvelle méthode permettant la localisation
de la falsification dans les signaux sonores. Aussi, une nouvelle méthode de protection du
droit d’auteur. Finalement, une nouvelle attaque perceptuelle, en utilisant le spikegramme,
pour attaquer des systèmes de tatouage sonore.
Nous proposons tout d’abord une technique de localisation des falsifications (‘tampering’)
des signaux sonores. Pour cela nous combinons une méthode à spectre étendu modifié
(‘modified spread spectrum’, MSS) avec une représentation parcimonieuse. Nous utilisons
une technique de poursuite perceptive adaptée (perceptual marching pursuit, PMP [Hossein
Najaf-Zadeh, 2008]) pour générer une représentation parcimonieuse (spikegramme) du
signal sonore d’entrée qui est invariante au décalage temporel [E. C. Smith, 2006] et qui
prend en compte les phénomènes de masquage tels qu’ils sont observés en audition. Un code
d’authentification est inséré à l’intérieur des coefficients de la représentation en spikegramme.
Puis ceux-ci sont combinés aux seuils de masquage. Le signal tatoué est resynthétisé Ã
partir des coefficients modifiés, et le signal ainsi obtenu est transmis au décodeur. Au
décodeur, pour identifier un segment falsifié du signal sonore, les codes d’authentification de
tous les segments intacts sont analysés. Si les codes ne peuvent être détectés correctement,
on sait qu’alors le segment aura été falsifié. Nous proposons de tatouer selon le principe
à spectre étendu (appelé MSS) afin d’obtenir une grande capacité en nombre de bits de
tatouage introduits. Dans les situations où il y a désynchronisation entre le codeur et le
décodeur, notre méthode permet quand même de détecter des pièces falsifiées. Par rapport
à l’état de l’art, notre approche a le taux d’erreur le plus bas pour ce qui est de détecter
les pièces falsifiées. Nous avons utilisé le test de l’opinion moyenne (‘MOS’) pour mesurer
la qualité des systèmes tatoués. Nous évaluons la méthode de tatouage semi-fragile par
le taux d’erreur (nombre de bits erronés divisé par tous les bits soumis) suite à plusieurs
attaques. Les résultats confirment la supériorité de notre approche pour la localisation des
pièces falsifiées dans les signaux sonores tout en préservant la qualité des signaux.
Ensuite nous proposons une nouvelle technique pour la protection des signaux sonores.
Cette technique est basée sur la représentation par spikegrammes des signaux sonores
et utilise deux dictionnaires (TDA pour Two-Dictionary Approach). Le spikegramme est
utilisé pour coder le signal hôte en utilisant un dictionnaire de filtres gammatones. Pour
le tatouage, nous utilisons deux dictionnaires différents qui sont sélectionnés en fonction
du bit d’entrée à tatouer et du contenu du signal. Notre approche trouve les gammatones appropriés (appelés noyaux de tatouage) sur la base de la valeur du bit à tatouer, et
incorpore les bits de tatouage dans la phase des gammatones du tatouage. De plus, il
est montré que la TDA est libre d’erreur dans le cas d’aucune situation d’attaque. Il est
démontré que la décorrélation des noyaux de tatouage permet la conception d’une méthode
de tatouage sonore très robuste.
Les expériences ont montré la meilleure robustesse pour la méthode proposée lorsque le
signal tatoué est corrompu par une compression MP3 à 32 kbits par seconde avec une
charge utile de 56.5 bps par rapport à plusieurs techniques récentes. De plus nous avons
étudié la robustesse du tatouage lorsque les nouveaux codec USAC (Unified Audion and
Speech Coding) à 24kbps sont utilisés. La charge utile est alors comprise entre 5 et 15 bps.
Finalement, nous utilisons les spikegrammes pour proposer trois nouvelles méthodes
d’attaques. Nous les comparons aux méthodes récentes d’attaques telles que 32 kbps MP3
et 24 kbps USAC. Ces attaques comprennent l’attaque par PMP, l’attaque par bruit
inaudible et l’attaque de remplacement parcimonieuse. Dans le cas de l’attaque par PMP,
le signal de tatouage est représenté et resynthétisé avec un spikegramme. Dans le cas de
l’attaque par bruit inaudible, celui-ci est généré et ajouté aux coefficients du spikegramme.
Dans le cas de l’attaque de remplacement parcimonieuse, dans chaque segment du signal,
les caractéristiques spectro-temporelles du signal (les décharges temporelles ;‘time spikes’)
se trouvent en utilisant le spikegramme et les spikes temporelles et similaires sont remplacés
par une autre.
Pour comparer l’efficacité des attaques proposées, nous les comparons au décodeur du
tatouage à spectre étendu. Il est démontré que l’attaque par remplacement parcimonieux
réduit la corrélation normalisée du décodeur de spectre étendu avec un plus grand facteur
par rapport à la situation où le décodeur de spectre étendu est attaqué par la transformation MP3 (32 kbps) et 24 kbps USAC.Abstract : Every year global music piracy is making billion dollars of economic, job, workers’ earnings
losses and also million dollars loss in tax revenues. Most of the music piracy is because of
rapid growth and easiness of current technologies for copying, sharing, manipulating and
distributing musical data [Domingo, 2015], [Siwek, 2007]. Audio watermarking has been
proposed as one approach for copyright protection and tamper localization of audio signals
to prevent music piracy. In this thesis, we use the spikegram- which is a bio-inspired sparse
representation- to propose a novel approach to design an audio tamper localization method
as well as an audio copyright protection method and also a new perceptual attack against
any audio watermarking system.
First, we propose a tampering localization method for audio signal, based on a Modified
Spread Spectrum (MSS) approach. Perceptual Matching Pursuit (PMP) is used to compute
the spikegram (which is a sparse and time-shift invariant representation of audio signals) as
well as 2-D masking thresholds. Then, an authentication code (which includes an Identity
Number, ID) is inserted inside the sparse coefficients. For high quality watermarking, the
watermark data are multiplied with masking thresholds. The time domain watermarked
signal is re-synthesized from the modified coefficients and the signal is sent to the decoder.
To localize a tampered segment of the audio signal, at the decoder, the ID’s associated to
intact segments are detected correctly, while the ID associated to a tampered segment is
mis-detected or not detected. To achieve high capacity, we propose a modified version of
the improved spread spectrum watermarking called MSS (Modified Spread Spectrum). We
performed a mean opinion test to measure the quality of the proposed watermarking system.
Also, the bit error rates for the presented tamper localization method are computed under
several attacks. In comparison to conventional methods, the proposed tamper localization
method has the smallest number of mis-detected tampered frames, when only one frame
is tampered. In addition, the mean opinion test experiments confirms that the proposed
method preserves the high quality of input audio signals.
Moreover, we introduce a new audio watermarking technique based on a kernel-based
representation of audio signals. A perceptive sparse representation (spikegram) is combined
with a dictionary of gammatone kernels to construct a robust representation of sounds.
Compared to traditional phase embedding methods where the phase of signal’s Fourier
coefficients are modified, in this method, the watermark bit stream is inserted by modifying
the phase of gammatone kernels. Moreover, the watermark is automatically embedded only
into kernels with high amplitudes where all masked (non-meaningful) gammatones have
been already removed. Two embedding methods are proposed, one based on the watermark
embedding into the sign of gammatones (one dictionary method) and another one based
on watermark embedding into both sign and phase of gammatone kernels (two-dictionary
method). The robustness of the proposed method is shown against 32 kbps MP3 with
an embedding rate of 56.5 bps while the state of the art payload for 32 kbps MP3 robust
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watermarking is lower than 50.3 bps. Also, we showed that the proposed method is robust
against unified speech and audio codec (24 kbps USAC, Linear predictive and Fourier
domain modes) with an average payload of 5 − 15 bps. Moreover, it is shown that the
proposed method is robust against a variety of signal processing transforms while preserving
quality.
Finally, three perceptual attacks are proposed in the perceptual sparse domain using
spikegram. These attacks are called PMP, inaudible noise adding and the sparse replacement
attacks. In PMP attack, the host signals are represented and re-synthesized with
spikegram. In inaudible noise attack, the inaudible noise is generated and added to the
spikegram coefficients. In sparse replacement attack, each specific frame of the spikegram
representation - when possible - is replaced with a combination of similar frames located
in other parts of the spikegram. It is shown than the PMP and inaudible noise attacks
have roughly the same efficiency as the 32 kbps MP3 attack, while the replacement attack
reduces the normalized correlation of the spread spectrum decoder with a greater factor
than when attacking with 32 kbps MP3 or 24 kbps unified speech and audio coding (USAC)
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