1,418 research outputs found
Roadmap on optical security
Postprint (author's final draft
Optical image compression and encryption methods
International audienceOver the years extensive studies have been carried out to apply coherent optics methods in real-time communications and image transmission. This is especially true when a large amount of information needs to be processed, e.g., in high-resolution imaging. The recent progress in data-processing networks and communication systems has considerably increased the capacity of information exchange. However, the transmitted data can be intercepted by nonauthorized people. This explains why considerable effort is being devoted at the current time to data encryption and secure transmission. In addition, only a small part of the overall information is really useful for many applications. Consequently, applications can tolerate information compression that requires important processing when the transmission bit rate is taken into account. To enable efficient and secure information exchange, it is often necessary to reduce the amount of transmitted information. In this context, much work has been undertaken using the principle of coherent optics filtering for selecting relevant information and encrypting it. Compression and encryption operations are often carried out separately, although they are strongly related and can influence each other. Optical processing methodologies, based on filtering, are described that are applicable to transmission and/or data storage. Finally, the advantages and limitations of a set of optical compression and encryption methods are discussed
A DNA Based Colour Image Encryption Scheme Using A Convolutional Autoencoder
With the advancement in technology, digital images can easily be transmitted
and stored over the Internet. Encryption is used to avoid illegal interception
of digital images. Encrypting large-sized colour images in their original
dimension generally results in low encryption/decryption speed along with
exerting a burden on the limited bandwidth of the transmission channel. To
address the aforementioned issues, a new encryption scheme for colour images
employing convolutional autoencoder, DNA and chaos is presented in this paper.
The proposed scheme has two main modules, the dimensionality conversion module
using the proposed convolutional autoencoder, and the encryption/decryption
module using DNA and chaos. The dimension of the input colour image is first
reduced from N M 3 to P Q gray-scale image using the
encoder. Encryption and decryption are then performed in the reduced dimension
space. The decrypted gray-scale image is upsampled to obtain the original
colour image having dimension N M 3. The training and
validation accuracy of the proposed autoencoder is 97% and 95%, respectively.
Once the autoencoder is trained, it can be used to reduce and subsequently
increase the dimension of any arbitrary input colour image. The efficacy of the
designed autoencoder has been demonstrated by the successful reconstruction of
the compressed image into the original colour image with negligible perceptual
distortion. The second major contribution presented in this paper is an image
encryption scheme using DNA along with multiple chaotic sequences and
substitution boxes. The security of the proposed image encryption algorithm has
been gauged using several evaluation parameters, such as histogram of the
cipher image, entropy, NPCR, UACI, key sensitivity, contrast, etc. encryption
Secure and efficient storage of multimedia: content in public cloud environments using joint compression and encryption
The Cloud Computing is a paradigm still with many unexplored areas ranging from the
technological component to the de nition of new business models, but that is revolutionizing the way we design, implement and manage the entire infrastructure of information technology.
The Infrastructure as a Service is the delivery of computing infrastructure, typically a virtual data center, along with a set of APIs that allow applications, in an automatic way, can control the resources they wish to use. The choice of the service provider and how it applies to their business model may lead to higher or lower cost in the operation and maintenance of applications near the suppliers.
In this sense, this work proposed to carry out a literature review on the topic of Cloud
Computing, secure storage and transmission of multimedia content, using lossless compression, in public cloud environments, and implement this system by building an application that manages data in public cloud environments (dropbox and meocloud).
An application was built during this dissertation that meets the objectives set. This system provides the user a wide range of functions of data management in public cloud environments, for that the user only have to login to the system with his/her credentials, after performing the login, through the Oauth 1.0 protocol (authorization protocol) is generated an access token, this token is generated only with the consent of the user and allows the application to get access to data/user les without having to use credentials. With this token the framework can now operate and unlock the full potential of its functions. With this application
is also available to the user functions of compression and encryption so that user can make the most of his/her cloud storage system securely. The compression function works using the compression algorithm LZMA being only necessary for the user to choose the les to be compressed.
Relatively to encryption it will be used the encryption algorithm AES (Advanced Encryption Standard) that works with a 128 bit symmetric key de ned by user.
We build the research into two distinct and complementary parts: The rst part consists
of the theoretical foundation and the second part is the development of computer application where the data is managed, compressed, stored, transmitted in various environments of cloud computing. The theoretical framework is organized into two chapters, chapter 2 - Background
on Cloud Storage and chapter 3 - Data compression.
Sought through theoretical foundation demonstrate the relevance of the research, convey some of the pertinent theories and input whenever possible, research in the area. The second part of the work was devoted to the development of the application in cloud environment.
We showed how we generated the application, presented the features, advantages, and
safety standards for the data. Finally, we re ect on the results, according to the theoretical
framework made in the rst part and platform development.
We think that the work obtained is positive and that ts the goals we set ourselves
to achieve. This research has some limitations, we believe that the time for completion was scarce and the implementation of the platform could bene t from the implementation of other features.In future research it would be appropriate to continue the project expanding the capabilities
of the application, test the operation with other users and make comparative tests.A Computação em nuvem é um paradigma ainda com muitas áreas por explorar que
vão desde a componente tecnológica à definição de novos modelos de negócio, mas que está
a revolucionar a forma como projetamos, implementamos e gerimos toda a infraestrutura da
tecnologia da informação.
A Infraestrutura como Serviço representa a disponibilização da infraestrutura computacional,
tipicamente um datacenter virtual, juntamente com um conjunto de APls que permitirá
que aplicações, de forma automática, possam controlar os recursos que pretendem utilizar_ A
escolha do fornecedor de serviços e a forma como este aplica o seu modelo de negócio poderão
determinar um maior ou menor custo na operacionalização e manutenção das aplicações junto
dos fornecedores.
Neste sentido, esta dissertação propôs· se efetuar uma revisão bibliográfica sobre a
temática da Computação em nuvem, a transmissão e o armazenamento seguro de conteúdos
multimédia, utilizando a compressão sem perdas, em ambientes em nuvem públicos, e implementar
um sistema deste tipo através da construção de uma aplicação que faz a gestão dos
dados em ambientes de nuvem pública (dropbox e meocloud).
Foi construída uma aplicação no decorrer desta dissertação que vai de encontro aos objectivos
definidos. Este sistema fornece ao utilizador uma variada gama de funções de gestão
de dados em ambientes de nuvem pública, para isso o utilizador tem apenas que realizar o login
no sistema com as suas credenciais, após a realização de login, através do protocolo Oauth 1.0
(protocolo de autorização) é gerado um token de acesso, este token só é gerado com o consentimento
do utilizador e permite que a aplicação tenha acesso aos dados / ficheiros do utilizador
~em que seja necessário utilizar as credenciais. Com este token a aplicação pode agora operar e
disponibilizar todo o potencial das suas funções. Com esta aplicação é também disponibilizado
ao utilizador funções de compressão e encriptação de modo a que possa usufruir ao máximo
do seu sistema de armazenamento cloud com segurança. A função de compressão funciona
utilizando o algoritmo de compressão LZMA sendo apenas necessário que o utilizador escolha os
ficheiros a comprimir. Relativamente à cifragem utilizamos o algoritmo AES (Advanced Encryption
Standard) que funciona com uma chave simétrica de 128bits definida pelo utilizador.
Alicerçámos a investigação em duas partes distintas e complementares: a primeira parte
é composta pela fundamentação teórica e a segunda parte consiste no desenvolvimento da aplicação
informática em que os dados são geridos, comprimidos, armazenados, transmitidos em
vários ambientes de computação em nuvem. A fundamentação teórica encontra-se organizada
em dois capítulos, o capítulo 2 - "Background on Cloud Storage" e o capítulo 3 "Data Compression",
Procurámos, através da fundamentação teórica, demonstrar a pertinência da investigação. transmitir algumas das teorias pertinentes e introduzir, sempre que possível, investigações
existentes na área. A segunda parte do trabalho foi dedicada ao desenvolvimento da
aplicação em ambiente "cloud". Evidenciámos o modo como gerámos a aplicação, apresentámos
as funcionalidades, as vantagens. Por fim, refletimos sobre os resultados , de acordo com o
enquadramento teórico efetuado na primeira parte e o desenvolvimento da plataforma.
Pensamos que o trabalho obtido é positivo e que se enquadra nos objetivos que nos propusemos
atingir. Este trabalho de investigação apresenta algumas limitações, consideramos que
o tempo para a sua execução foi escasso e a implementação da plataforma poderia beneficiar
com a implementação de outras funcionalidades. Em investigações futuras seria pertinente dar continuidade ao projeto ampliando as potencialidades da aplicação, testar o funcionamento
com outros utilizadores e efetuar testes comparativos.Fundação para a Ciência e a Tecnologia (FCT
Toward Free and Open Source Film Projection for Digital Cinema
International audienceCinema industry has chosen Digital Cinema Package (DCP) as encoding format for the distribution of digital films. DCP uses JPEG2000 for video compression. An efficient implementation of coding and decoding for this format is complex, however. Currently deployed equipment is expensive and has high maintenance costs, preventing art-house cinema theaters from acquiring it. Therefore, we conduct this research activity in cooperation with Utopia cinemas, a group of art-house cinemas, whose main requirement (besides functional ones) is to provide Free and Open Source Software (FOSS). This paper presents a solution that achieves real-time JPEG2000 decoding and DCP presentation based on widespread open source multimedia tools, namely VLC and libavcodec library. We present the improvements that were made in VLC to support the DCP packaging format, as well as details on JPEG2000 decoding inside libavcodec (optimization and lossy decoding). We also evaluate the performance of the decoding chai
EFFICIENT COMPRESSION AND ENCRYPTION SCHEME FOR SECURE TRANSMISSION OF IMAGES AND ITS RECONSTRUCTION
When it is desired to transmit redundant data over an insecure and bandwidth-constrained channel, it is customary to first compress the data and then encrypt it. In this paper, we investigate the efficiency of reversing the order of these steps, i.e., first encrypting and then compressing, without compromise for compression efficiency or the informationtheoretic security. A pseudorandom permutation and a linear encoding scheme is used to encrypt an original image, and the encrypted data are efficiently compressed by discarding the excessively rough and fine information of coefficients generated from orthogonal transform. After receiving the compressed data, based on spatial correlation, a receiver can reconstruct the principal content of the original image by iteratively updating the values of coefficients and the linear decoding procedure
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