A strong construction of S-box using Mandelbrot set an image encryption scheme

The substitution box (S-box) plays a vital role in creating confusion during the encryption process of digital data. The quality of encryption schemes depends upon the S-box. There have been several attempts to enhance the quality of the S-box by using fractal chaotic mechanisms. However, there is still weakness in the robustness against cryptanalysis of fractal-based S-boxes. Due to their chaotic behavior, fractals are frequently employed to achieve randomness by confusion and diffusion process. A complex number-based S-box and a chaotic map diffusion are proposed to achieve high nonlinearity and low correlation. This study proposed a Mandelbrot set S-box construction based on the complex number and Chen chaotic map for resisting cryptanalytic attacks by creating diffusion in our proposed algorithm. The cryptosystem was built on the idea of substitution permutation networks (SPN). The complex nature of the proposed S-box makes it more random than other chaotic maps. The robustness of the proposed system was analyzed by different analysis properties of the S-box, such as nonlinearity, strict avalanche criterion, Bit independent criterion, and differential and linear probability. Moreover, to check the strength of the proposed S-box against differential and brute force attacks, we performed image encryption with the proposed S-box. The security analysis was performed, including statistical attack analysis and NIST analysis. The analysis results show that the proposed system achieves high-security standards than existing schemes

Noise-Resistant Image Encryption Scheme for Medical Images in the Chaos and Wavelet Domain

In this paper, a noise-resistant image encryption scheme is proposed. We have used a cubic-logistic map, Discrete Wavelet Transform (DWT), and bit-plane extraction method to encrypt the medical images at the bit-level rather than pixel-level. The proposed work is divided into three sections; In the first and the last section, the image is encrypted in the spatial domain. While the middle section of the proposed algorithm is devoted to the frequency domain encryption in which DWT is incorporated. As the frequency domain encryption section is a sandwich between the two spatial domain encryption sections, we called it a ”sandwich encryption.” The proposed algorithm is lossless because it can decrypt the exact pixel values of an image. Along with this, we have also gauge the proposed scheme's performance using statistical analysis such as entropy, correlation, and contrast. The entropy values of the cipher images generated from the proposed encryption scheme are more remarkable than 7.99, while correlation values are very close to zero. Furthermore, the number of pixel change rate (NPCR) and unified average change intensity (UACI) for the proposed encryption scheme is higher than 99.4% and 33, respectively. We have also tested the proposed algorithm by performing attacks such as cropping and noise attacks on enciphered images, and we found that the proposed algorithm can decrypt the plaintext image with little loss of information, but the content of the original image is visible

Application of Stochastic Diffusion for Hiding High Fidelity Encrypted Images

Cryptography coupled with information hiding has received increased attention in recent years and has become a major research theme because of the importance of protecting encrypted information in any Electronic Data Interchange system in a way that is both discrete and covert. One of the essential limitations in any cryptography system is that the encrypted data provides an indication on its importance which arouses suspicion and makes it vulnerable to attack. Information hiding of Steganography provides a potential solution to this issue by making the data imperceptible, the security of the hidden information being a threat only if its existence is detected through Steganalysis. This paper focuses on a study methods for hiding encrypted information, specifically, methods that encrypt data before embedding in host data where the ‘data’ is in the form of a full colour digital image. Such methods provide a greater level of data security especially when the information is to be submitted over the Internet, for example, since a potential attacker needs to first detect, then extract and then decrypt the embedded data in order to recover the original information. After providing an extensive survey of the current methods available, we present a new method of encrypting and then hiding full colour images in three full colour host images with out loss of fidelity following data extraction and decryption. The application of this technique, which is based on a technique called ‘Stochastic Diffusion’ are wide ranging and include covert image information interchange, digital image authentication, video authentication, copyright protection and digital rights management of image data in general

Multimedia

The nowadays ubiquitous and effortless digital data capture and processing capabilities offered by the majority of devices, lead to an unprecedented penetration of multimedia content in our everyday life. To make the most of this phenomenon, the rapidly increasing volume and usage of digitised content requires constant re-evaluation and adaptation of multimedia methodologies, in order to meet the relentless change of requirements from both the user and system perspectives. Advances in Multimedia provides readers with an overview of the ever-growing field of multimedia by bringing together various research studies and surveys from different subfields that point out such important aspects. Some of the main topics that this book deals with include: multimedia management in peer-to-peer structures & wireless networks, security characteristics in multimedia, semantic gap bridging for multimedia content and novel multimedia applications

Towards intelligent aquaculture. Development of an early Biological Warning System to monitor exposure to contaminants and fish welfare: from artificial vision to systems modelling

161 p.Etorkizun hurbilera begira gizakion kopurua ez ezik (Gerland et al., 2014; United Nations, 2014), itsas elikagaien ekoizpenaren eta kontsumoaren hazkundea espero da. Azken honen hazkundeak, batipat, akuikulturak bideratuko du (German Advisory Council on Global Change - WBGU, 2013). Akuikultura, ekoizpena handiagotzeko helburuagaz, itsas organismoen hazkunde kontrolatua da. Bertatik lortzen diren produktuak era askotakoak izan daitezke: arrainak, moluskuak, krustazeoak, algak eta itsas landareak dira ezagunenak. Baina kokodriloak, dortokak eta beste motatako zenbait animalia urlehortarrak ere ekoizten dira. Era berean, akuikultura instalazioek kokapen desberdinak euki ditzakete: itsas kostaldean zein itsasadarretan baina lur barnean zein ibai edo lakuen ondoan ere aurkitu daitezke.Beste edozein ekoizpen prozesu bezala, sortzen diren produktuen kalitatea erronka garrantzitsuenetariko bat da. Eta kalitatea, kontuan izanda sortzen diren produktuak gizakion kontsumorako direla, ekoiztutako animalien osasungarritasunarekin bat doa. Kezkarik garrantzitsuenetarikoa itsas elikagaien ekoizpenean ur ingurugiroan dauden kutsatzatzaileek ekoiztutako produktuetan duten efektua da. Kutsatzaileak gero eta kantitate haundiagoetan azaltzen dira eta gainera, gero eta kutsatzaile berri gehiago agertzen dira (Bevan et al., 2012; Roose et al., 2011). Kutsatzaileak ez dira bakarrik uretara izurtzen, animaliei emoten zaien elikagaiak ere kutsatuta egon daitezke (Dahle et al., 2010; Dobson et al., 2008; Sharma and Paradakar, 2010). Hoierariko kutsatzaile askok ere, animalien ongizatean efektu negatiboak izaten dituzte eta galera ekonomiko haundiak sortarazten dituzte. Gaur egun, kutsatzaileak antzemateko metodo ez-inbasiboen galera dago. Hare eta gehiago, kutsatzaile berriak detektatzeko metodorik ez dago, antzemate metodoak kutsatzaile bakoitzeko ezpezifikoki diseinatsen direlako eta gero eta kutsatzaile berri gehiago detektatzen direlako, adibidez gizakion kontsumorako uran (Dahle et al., 2010; Roose et al., 2011).Tesi honek, monitorizazio metodologia ez inbasibo bat garatzen du non arrainak Alerta Sistema Biologikoa (Biological Warning System - BWS) giza erabiltzen dira. Arrainak, euren igeriketa jokabidea aztertuz, sensore bat balira kontzideratzen dira. Metodologia honen abantailarik esanguratsugarrienak dira: i) teknologia eskuragarria bideratzea, ii) monitorizazio on-line-a uzten duela eta iii) mota ezberdinetako kutsatzaileekin, ezagun ala ezezagun, lan egiteko ahalmena izango duela.Azkenik, proposatutako Alerta Sistema Biologikoa beste hierarkia handiagoko sistemekin egon beharko luke harremanetan eta sistema guzti hauen emaitzak ekoiztutako produktuen trazabilitate agiriekin batera joan beharko lukete azken produktuak merkatuara heltzerakoan. Hierarkia handiagoko sistema hauek Arrizku Analisis eta Punto Kritikoen Kontrol (Hazard Analysis and Critical Control Point - HACCP) eta Arrain Ongizate Segurtasun Sistemak (Fish Welfare Assurance System - FWAS) dira hain zuzen ere (van de Vis et al., 2012).HipotesiaTesi hau ondoko hipotesian oinarrituta dago:Arrain multzo batek sentsore biologiko bat izango balitz bezala jokatuko du; arrainen jokabidea, arrainen erantzun biologiko eta fisiologikoak batzen dituena, kanpo estimuluen aurrean modu ez inbasiboan neurtu daitekelako. Honek, arrain-sistemaren jokabidearen aldaketa on-line monitorizaziorako tresna gisa erabiltzea bideratzen du.Helburuak eta ekarpenakTesi honen helburu garrantzitsuena arrainak sentsore giza erabiliz, arrainen ongizatea on-line monitorizatzeko eta akuikultura industrian aplikatzeko tresna baten disenua eta eraikuntza da. Honetarako, jakintza alor anitzak jorratzen dira, hala nola biologia, etologia, ingurugiroaren ikuskaketa, arrainen ongizatea, elikagain kalitatearen fidagarritasuna, sistemen ingenieritza edota seinaleen prozesamendu ez-lineala.Lupia (Dicentrarchus labrax) izan da Tesi hau garatzeko aukeratutako arrain mota bi arrazoi nagusirengatik. Batetik, mediterraneo itsasoko herrialdeetako akuikultura produkzioan oso hedatuta dagoelako eta, aurrekoarekin loturik, lupiaren produkzioan arrainen ongizatearen eta azken produktuaren kalitatea oso garrantzitsua delako, gehienbat gizakion kontsumora bideraturiko produktua delako hain zuzen.Bigarren mailako helburuak, proposatutako tresnaren ebaluazioarekin lotuta egoteaz gain, diseinatutako sistemak aldagai ezberdinen menpean duen portaera aztertzen dute, hala nola:Arrain-sistemaren erantzuna arrain kopurua aldatuz.Arrain-sistemaren erantzuna arrainen dietari selenioa gehitzerakoan.Arrain-sistemaren erantzuna urari kutsatzaile neurotoxikoa den metilmekurioa gehitzerakoan.Hirugarren eta azken helburua, aurreko bi helburuen bitartez garatutako informazioa, ezagutza-eredu batetan isladatzearekin dator bat.Helburu hauekin loturik, Tesi honek ondoko ekarpenak ditu:Sistemen ingenieritzan oinarritutako lan metodologia berri bat garatu da.Ez-inbasiboa, moldakorra, merkea eta Alerta Sistema Biologiko sistema batetan egokitzeko gai den irudi analisian oinarritutako tresna bat garatu da.Perturbazio bati erantzunez arrain multzoaren mugimendu ereduan oinarrituriko sentsore bat garatu da.Arrainen multzoaren igeriketa ereduari aplikatu ahal zaizkion zenbait seinale prozesaketa metodo ez-lineala garatu dira.Arrainen erantzuna kanpotiko perturbazio baten aurrean modelatzen duen eredu matematikoa garatu da.Garatutako metodologia eta monitorizazio tresna zenbait kasu experimentaletan aztertu da.Ikerketa MetodologiaIkerketa metodologiaren aldetik, Glass-ek (1995) proposatutako pausu berdinak jarraitu dira. Honela, Tesia lau faseetan banaturik dago: jakinarazte fasea, fase proposizionala, fase analitikoa eta ebaluaketa fasea. Era berean, erabilitako metodologia zati zientifiko eta zati enpiriko baten batura da. Ikerketa metodologia honek erdiesten dituen onurak ondokoak dira:Erabilitako ikerketa metodologia arrainen multzoak eta bere ingurugiroak osatzen duten sistemaren dinamika ulertzeko ezin bestekoa izan da.Tesian garatuta tresna zenbait kasu partikularretan aztertu da. Honela, tresnaren onurak ez ezik bere mugak ere aztertu ahal izan dira.Garatutako tresna benetako akuikultura instalazio batetan inplementatzeko bideragarritasuna aztertu da Norbegiako ¿Centre for Autonomous Marine Operations and Systems (AMOS)¿ Ikerketa Zentruan hiru hilabeteko ikerketa egonaldiari esker. Egonaldia Europa Batasuneko ikerlari mugikortasun beka batekin finantziatu da ¿European Economic Area (EEA) Researcher Mobility and Co-operation Grant, NILS Science and Sustainability Programme.Publikatutako lanen maila, kalitatea eta irismena handiagotu da.Etorkizunean, ikerketa proiektu eta gertaeretan parte hartzeko ahalmenaren handiagotzea, ikerlariaren kontaktu sarearen handiagotzearekin batera.Azkenik, Tesiaren zati experimentalak Yin-en (1993) kasu-ikerketaren oinarriak jarraitzen ditu. Kasu-ikerketa metodoa ezagutza induktiboa sortzeko erabiltzen da eta eguneroko gertakari erreal eta komplexuei aplikatzerakoan baliagarritasun handia erakusten du.Lanaren GarapenaTesi honen lehenengo zatian, irudi analisian oinarritutako metodologia ez-inbasibo bat garatzen da. Metedologia hau, video grabaketa, irudi prozesaketa eta seinale ez-linealen analisi eta prozesaketan datza. Arrain multzoaren erantzuna gertaera estokastiko edo aleatorio baten aurrean aztertzen eta neurtzen da. Irudietan agertzen diren objetuen antzematea, fluxu optikoko algoritmo baten bitartez burutzen da. Honela arrainak detektatu ez ezik, irudien atzealdea eta bestelako efektu ez desiratuak ezabatzen dira. Azkenik, arrain multzoaren zentruak jarraitzen duen ibilbidea, Shannon (Shannon, 1951, 1948) eta permutazio entropia (Bandt and Pompe, 2002) batetik; eta Higuchi (1988), Katz (1988) eta Castiglioni-k (2010) proposatutako Katz algoritmoaren aldaketaren bitartezko dimentsio fraktal algoritmoez aztertzen da.Garatutako monitorizazio tresna hiru kasu partikularretan aztertu zen. Lehenengoan, hiru lupia multzo aztertu ziren. Horietariko bi antzekoak ziren (kontrolak eta elastomero batekin markatutakoak), eta hirugarrena aldiz, 9 egunez metilmerkuriodun (4 µg MeHg/L) uretan murgildutako arrainez osoturik zegoen. Shannon-en entropia eta Katz-Castiglioni-ren algoritmoek izan ziren emaitza onenak erakutzi zutenak. Esan daiteke biek, arrainen erantzunak modu ez inbasibo batean kuantifikatzeko garaian, ahalmen nahikoa erakutsi zutela. Hala ere, Katz-Castiglioni-ren algoritmoak Shannon-en entropia baino askoz ere pisu konputazional handiagoa erakutsi zuen.Hasiera baten, arrain multzoa osotzen zuten animalien kopurua inolako eraginik euki zitzakela animalia sistema osoaren jokabidean garatutako aztertze metodologiari dagokionez, ez zen uste. Honetan sakontzeko, bigarren kasu partikular bat diseinatu zen, non sistemako aldagai bakarra arrain kopurua zen. Bigarren kasu partikular honen helbururik garrantzitsuena sistemarentzako Lan Puntuaren zehazpena zen, hau da, arrainek inolako perturbazio barik daudeneko egoera dinamikoa. Monitorizazio tresna doitzeko eta perturbazioak egoera ¿normaletik¿ bereiztu ahal izateko, Lan Puntuaren zehazpena ezin bestekoa da. Honetarako bi experimentu disenatu ziren:Arrain kopuruaren murrizketa. Arrain kopurua 50etik 1era pasatu zen 4 asteren buruan (50, 25, 13 eta arrain 1 aste bakoitzeko).Arrain kopururaren hazkuntza. Sistema osotzen duten arrainen kopurua 1etik 5era hazi zen egunero arrain berri bat sartuz (1, 2, 3, 4 eta 5 arrain egun bakoitzeko).Hirugarren kasu partikularrean, aldiz, arrainen urari bi sustantzia ezberdin gehitu zitzaizkion. Batetik, sodio selenitoa (Na2SeO3, 10 µg/L) gehitu zitzaion 7 egunen zehar eta bestetik metilmerkurioa (4 µg MeHg/L) 14 egunen zehar.Tesiaren azken atalean, aurreko kasuetan garatutako jakituriarekin ezagutza eredu bat eraiki da. Eredua, 3 azpi-ereduez osatuta dago, zeintzuk sistemaren eguneroko erantzuna eta Shannon-en entropiaren emaitzak, egoera basalean, gertaera aleatorio bateri erantzunez eta azken bien arteko erlazioari begira, integratzen dituzte.OndorioakOndoren Tesiaren ondoriorik esanguratsuenak adierazten dira:Arrainen monitorizaziorako tresna garatu da. Tresnaren oinarrian irudi eskuraketa eta prozesaketa egoteaz gain, arrain multzoak osatzen duen zentruaren ibilbidearen analizi ez-lineala ere badago.Arrainen sistemaren dinamika aztertzeko garaian Shannon-en entropia parametrorik onena izan da.1 eta 5 arrainen artean, lubia arrain sistemaren Shannon-en entropia eta sistema osotzen duten arrain kopuruaren erlazioa oso estua da.Lubia arrain sistemaren eta Shannon-en entropiaren arteko erlazioa exponentziala da.Garatutako tresna kasu partikularrei aplikatzerakoan era egokian lan egin du. Honek, ikerketa lanaren hasierako Tesia berretsi du.Espero zen bezala eta garatutako tresnak konfirmatuta, urari gehitutako sodio selenito kontsentrazioak ez du inolako efekturik izan lubia sistemaren Shannon-en entropian.Era berean, garatutako tresnak konfirmatu du urari gehituriko metilmerkurioak efektu ezezkorra izan duela lubia sistemaren Shannon-en entropian.Tresnaren aplikazioak kasu partikularretan lubia sistemaren Shannon-en entropiaren eguneroko balioa ez ezik bere egunean-eguneko bilakaera kontutan hartu behar dela erakutsi du.Garatutako ezagutza eredua lubia arrain sistemaren jokabide erantsunaren eguneroko bilakaeran oinarrituriko 3 azpi-ereduz osoturik dago: Azpi-eredu basala, gertaera aleatorioaren erantzuneko azpi eredua eta aurreko biak erlazionatzen dituen azpi-eredua.Garatutako tresna, zenbait hobekuntzekin, on-line monitorizazio arkitektura batetan inplementatzeko gaitasuna duela esan daiteke. Eta beraz, era basatian nahiz akuikulturan, arrain multzoak monitorizatzeko edo/eta ur kutsadura antzemateko ingurumen-programetan tresna baliagarria izan daiteke.Beraz, ikerketa lan honen Tesia arrainak sentsore biologiko moduan erabil daitezkela da; kanpo perturbazioen eraginez euren portaeran agertzen diren aldaketak modu ez-inbasiboan neurtu daitezkelako.Gerorako LanaGaur egun Errezirkulazio Akuikultura Sistemek (Recirculating Aquaculture Systems - RAS) gero eta aplikazio handiagoa dute munduan zehar. Tesi honetan oinarrituriko teknologia baten garapenak zekulako erabilgarritasuna eukiko luke mota honetako sistemetan, batez ere, produkzio unitate osoa monitorizatu daitekelako. Era berean, ur kutsadura antzemateko ingurumen-programetan tresna baliagarria izan daiteke. Azken honetarako, teknologia honetan oinarrituriko ikusketa guneak garatu beharko lirateke.Urpean lan egiteak desabantail ugari ditu. Hau ekiditeko datu eskuraketa teknika ezberdinak aztertu beharko lirateke, hala nola izpi-infragorriak, sonar teknologia edota irudi hiperespektralak zenbait esatearren.Azkenik, teknologia honetatik lortutako datuak bestelako tekniken bidez lorturiko datuekin bat egin beharko lirateke. Honela, arrainen datu biokimiko, histologiko eta fisiologikoez gain, teknika ez-inbasiboen bidez neurtutako igeriketa jokabideak ere kontutan hartu beharreko parametroa izan beharko luke.Research Center for Experimental Marine Biology and Biotechnology - Plentzia Marine Station (PiE

Sparse image representation with encryption

In this thesis we present an overview of sparse approximations of grey level images. The sparse representations are realized by classic, Matching Pursuit (MP) based, greedy selection strategies. One such technique, termed Orthogonal Matching Pursuit (OMP), is shown to be suitable for producing sparse approximations of images, if they are processed in small blocks. When the blocks are enlarged, the proposed Self Projected Matching Pursuit (SPMP) algorithm, successfully renders equivalent results to OMP. A simple coding algorithm is then proposed to store these sparse approximations. This is shown, under certain conditions, to be competitive with JPEG2000 image compression standard. An application termed image folding, which partially secures the approximated images is then proposed. This is extended to produce a self contained folded image, containing all the information required to perform image recovery. Finally a modified OMP selection technique is applied to produce sparse approximations of Red Green Blue (RGB) images. These RGB approximations are then folded with the self contained approach

Recent Advances in Signal Processing

The signal processing task is a very critical issue in the majority of new technological inventions and challenges in a variety of applications in both science and engineering fields. Classical signal processing techniques have largely worked with mathematical models that are linear, local, stationary, and Gaussian. They have always favored closed-form tractability over real-world accuracy. These constraints were imposed by the lack of powerful computing tools. During the last few decades, signal processing theories, developments, and applications have matured rapidly and now include tools from many areas of mathematics, computer science, physics, and engineering. This book is targeted primarily toward both students and researchers who want to be exposed to a wide variety of signal processing techniques and algorithms. It includes 27 chapters that can be categorized into five different areas depending on the application at hand. These five categories are ordered to address image processing, speech processing, communication systems, time-series analysis, and educational packages respectively. The book has the advantage of providing a collection of applications that are completely independent and self-contained; thus, the interested reader can choose any chapter and skip to another without losing continuity

Efficient simultaneous encryption and compression of digital videos in computationally constrained applications

This thesis is concerned with the secure video transmission over open and wireless network channels. This would facilitate adequate interaction in computationally constrained applications among trusted entities such as in disaster/conflict zones, secure airborne transmission of videos for intelligence/security or surveillance purposes, and secure video communication for law enforcing agencies in crime fighting or in proactive forensics. Video content is generally too large and vulnerable to eavesdropping when transmitted over open network channels so that compression and encryption become very essential for storage and/or transmission. In terms of security, wireless channels, are more vulnerable than other kinds of mediums to a variety of attacks and eavesdropping. Since wireless communication is the main mode in the above applications, protecting video transmissions from unauthorized access through such network channels is a must. The main and multi-faceted challenges that one faces in implementing such a task are related to competing, and to some extent conflicting, requirements of a number of standard control factors relating to the constrained bandwidth, reasonably high image quality at the receiving end, the execution time, and robustness against security attacks. Applying both compression and encryption techniques simultaneously is a very tough challenge due to the fact that we need to optimize the compression ratio, time complexity, security and the quality simultaneously. There are different available image/video compression schemes that provide reasonable compression while attempting to maintain image quality, such as JPEG, MPEG and JPEG2000. The main approach to video compression is based on detecting and removing spatial correlation within the video frames as well as temporal correlations across the video frames. Temporal correlations are expected to be more evident across sequences of frames captured within a short period of time (often a fraction of a second). Correlation can be measured in terms of similarity between blocks of pixels. Frequency domain transforms such as the Discrete Cosine Transform (DCT) and the Discrete Wavelet Transform (DWT) have both been used restructure the frequency content (coefficients) to become amenable for efficient detection. JPEG and MPEG use DCT while JPEG2000 uses DWT. Removing spatial/temporal correlation encodes only one block from each class of equivalent (i.e. similar) blocks and remembering the position of all other block within the equivalence class. JPEG2000 compressed images achieve higher image quality than JPEG for the same compression ratios, while DCT based coding suffer from noticeable distortion at high compression ratio but when applied to any block it is easy to isolate the significant coefficients from the non-significant ones. Efficient video encryption in computationally constrained applications is another challenge on its own. It has long been recognised that selective encryption is the only viable approach to deal with the overwhelming file size. Selection can be made in the spatial or frequency domain. Efficiency of simultaneous compression and encryption is a good reason for us to apply selective encryption in the frequency domain. In this thesis we develop a hybrid of DWT and DCT for improved image/video compression in terms of image quality, compression ratio, bandwidth, and efficiency. We shall also investigate other techniques that have similar properties to the DCT in terms of representation of significant wavelet coefficients. The statistical properties of wavelet transform high frequency sub-bands provide one such approach, and we also propose phase sensing as another alternative but very efficient scheme. Simultaneous compression and encryption, in our investigations, were aimed at finding the best way of applying these two tasks in parallel by selecting some wavelet sub-bands for encryptions and applying compression on the other sub-bands. Since most spatial/temporal correlation appear in the high frequency wavelet sub-bands and the LL sub-bands of wavelet transformed images approximate the original images then we select the LL-sub-band data for encryption and the non-LL high frequency sub-band coefficients for compression. We also follow the common practice of using stream ciphers to meet efficiency requirements of real-time transmission. For key stream generation we investigated a number of schemes and the ultimate choice will depend on robustness to attacks. The still image (i.e. RF’s) are compressed with a modified EZW wavelet scheme by applying the DCT on the blocks of the wavelet sub-bands, selecting appropriate thresholds for determining significance of coefficients, and encrypting the EZW thresholds only with a simple 10-bit LFSR cipher This scheme is reasonably efficient in terms of processing time, compression ratio, image quality, as well was security robustness against statistical and frequency attack. However, many areas for improvements were identified as necessary to achieve the objectives of the thesis. Through a process of refinement we developed and tested 3 different secure efficient video compression schemes, whereby at each step we improve the performance of the scheme in the previous step. Extensive experiments are conducted to test performance of the new scheme, at each refined stage, in terms of efficiency, compression ratio, image quality, and security robustness. Depending on the aspects of compression that needs improvement at each refinement step, we replaced the previous block coding scheme with a more appropriate one from among the 3 above mentioned schemes (i.e. DCT, Edge sensing and phase sensing) for the reference frames or the non-reference ones. In subsequent refinement steps we apply encryption to a slightly expanded LL-sub-band using successively more secure stream ciphers, but with different approaches to key stream generation. In the first refinement step, encryption utilized two LFSRs seeded with three secret keys to scramble the significant wavelet LL-coefficients multiple times. In the second approach, the encryption algorithm utilises LFSR to scramble the wavelet coefficients of the edges extracted from the low frequency sub-band. These edges are mapped from the high frequency sub-bands using different threshold. Finally, use a version of the A5 cipher combined with chaotic logistic map to encrypt the significant parameters of the LL sub-band. Our empirical results show that the refinement process achieves the ultimate objectives of the thesis, i.e. efficient secure video compression scheme that is scalable in terms of the frame size at about 100 fps and satisfying the following features; high compression, reasonable quality, and resistance to the statistical, frequency and the brute force attack with low computational processing. Although image quality fluctuates depending on video complexity, in the conclusion we recommend an adaptive implementation of our scheme. Although this thesis does not deal with transmission tasks but the efficiency achieved in terms of video encryption and compression time as well as in compression ratios will be sufficient for real-time secure transmission of video using commercially available mobile computing devices