On the Design of Perceptual MPEG-Video Encryption Algorithms

In this paper, some existing perceptual encryption algorithms of MPEG videos are reviewed and some problems, especially security defects of two recently proposed MPEG-video perceptual encryption schemes, are pointed out. Then, a simpler and more effective design is suggested, which selectively encrypts fixed-length codewords (FLC) in MPEG-video bitstreams under the control of three perceptibility factors. The proposed design is actually an encryption configuration that can work with any stream cipher or block cipher. Compared with the previously-proposed schemes, the new design provides more useful features, such as strict size-preservation, on-the-fly encryption and multiple perceptibility, which make it possible to support more applications with different requirements. In addition, four different measures are suggested to provide better security against known/chosen-plaintext attacks.Comment: 10 pages, 5 figures, IEEEtran.cl

Simultaneous Visual Cryptography

A visual cryptography scheme (VCS), as proposed by M. Naor and A. Shamir, encodes a secret image into n different shares. The scheme ensures that only certain designated combinations of shares can recover the original image, while other combinations yield, in probabilistic sense, no information about the secret image. In this thesis, we show that there exist simultaneous visual cryptography schemes (SVCS), i.e. cryptographic schemes that allow for multiple secret images to be encoded across a set of n shares. The essential part of this research is to derive a set of formal definitions used to construct a valid SVCS and to design and examine different approaches for establishing valid SVCS constructions. In particular, we describe an SVCS that allows encoding n 1 distinct secret images across a set of n shares, and include a program that demonstrates the successful use of this SVCS in the appendix

Image Security using Visual Cryptography

Informations are being transferred through open channels and the security of those informations has been prime concerns. Apart from many conventional cryptographic schemes, visual cryptographic techniques have also been in use for data and information security. Visual cryptography is a secret sharing scheme as it breaks an original image into image shares such that, when the shares are stacked on one another, a hidden secret image is revealed. The Visual Cryptography Scheme is a secure method that encrypts a secret document or image by breaking it into image shares. A unique property of Visual Cryptography Scheme is that one can visually decode the secret image by superimposing shares without computation. Even to make the visual cryptography image shares more secure, public key encryption scheme is applied. Public key encryption technique makes image shares so secure that it becomes very hard for a third party to decode the secret image information without having required data that is a private key

A NOVEL JOINT PERCEPTUAL ENCRYPTION AND WATERMARKING SCHEME (JPEW) WITHIN JPEG FRAMEWORK

Due to the rapid growth in internet and multimedia technologies, many new commercial applications like video on demand (VOD), pay-per-view and real-time multimedia broadcast etc, have emerged. To ensure the integrity and confidentiality of the multimedia content, the content is usually watermarked and then encrypted or vice versa. If the multimedia content needs to be watermarked and encrypted at the same time, the watermarking function needs to be performed first followed by encryption function. Hence, if the watermark needs to be extracted then the multimedia data needs to be decrypted first followed by extraction of the watermark. This results in large computational overhead. The solution provided in the literature for this problem is by using what is called partial encryption, in which media data are partitioned into two parts - one to be watermarked and the other is encrypted. In addition, some multimedia applications i.e. video on demand (VOD), Pay-TV, pay-per-view etc, allow multimedia content preview which involves „perceptual‟ encryption wherein all or some selected part of the content is, perceptually speaking, distorted with an encryption key. Up till now no joint perceptual encryption and watermarking scheme has been proposed in the literature. In this thesis, a novel Joint Perceptual Encryption and Watermarking (JPEW) scheme is proposed that is integrated within JPEG standard. The design of JPEW involves the design and development of both perceptual encryption and watermarking schemes that are integrated in JPEG and feasible within the „partial‟ encryption framework. The perceptual encryption scheme exploits the energy distribution of AC components and DC components bitplanes of continuous-tone images and is carried out by selectively encrypting these AC coefficients and DC components bitplanes. The encryption itself is based on a chaos-based permutation reported in an earlier work. Similarly, in contrast to the traditional watermarking schemes, the proposed watermarking scheme makes use of DC component of the image and it is carried out by selectively substituting certain bitplanes of DC components with watermark bits. vi ii Apart from the aforesaid JPEW, additional perceptual encryption scheme, integrated in JPEG, has also been proposed. The scheme is outside of joint framework and implements perceptual encryption on region of interest (ROI) by scrambling the DCT blocks of the chosen ROI. The performances of both, perceptual encryption and watermarking schemes are evaluated and compared with Quantization Index modulation (QIM) based watermarking scheme and reversible Histogram Spreading (RHS) based perceptual encryption scheme. The results show that the proposed watermarking scheme is imperceptible and robust, and suitable for authentication. Similarly, the proposed perceptual encryption scheme outperforms the RHS based scheme in terms of number of operations required to achieve a given level of perceptual encryption and provides control over the amount of perceptual encryption. The overall security of the JPEW has also been evaluated. Additionally, the performance of proposed separate perceptual encryption scheme has been thoroughly evaluated in terms of security and compression efficiency. The scheme is found to be simpler in implementation, have insignificant effect on compression ratios and provide more options for the selection of control factor

Mixing Biometric Data For Generating Joint Identities and Preserving Privacy

Biometrics is the science of automatically recognizing individuals by utilizing biological traits such as fingerprints, face, iris and voice. A classical biometric system digitizes the human body and uses this digitized identity for human recognition. In this work, we introduce the concept of mixing biometrics. Mixing biometrics refers to the process of generating a new biometric image by fusing images of different fingers, different faces, or different irises. The resultant mixed image can be used directly in the feature extraction and matching stages of an existing biometric system. In this regard, we design and systematically evaluate novel methods for generating mixed images for the fingerprint, iris and face modalities. Further, we extend the concept of mixing to accommodate two distinct modalities of an individual, viz., fingerprint and iris. The utility of mixing biometrics is demonstrated in two different applications. The first application deals with the issue of generating a joint digital identity. A joint identity inherits its uniqueness from two or more individuals and can be used in scenarios such as joint bank accounts or two-man rule systems. The second application deals with the issue of biometric privacy, where the concept of mixing is used for de-identifying or obscuring biometric images and for generating cancelable biometrics. Extensive experimental analysis suggests that the concept of biometric mixing has several benefits and can be easily incorporated into existing biometric systems

A Spatial Domain Image Steganography Technique Based on Plane Bit Substitution Method

Steganography is the art and science of hiding information by embedding data into cover media. In this paper we propose a new method of information hiding in digital image in spatial domain. In this method we use Plane Bit Substitution Method (PBSM) technique in which message bits are embedded into the pixel value(s) of an image. We first, proposed a Steganography transformation machine (STM) for solving Binary operation for manipulation of original image with help to least significant bit (LSB) operator based matching. Second, we use pixel encryption and decryption techniques under theoretical and experimental evolution. Our experimental, techniques are sufficient to discriminate analysis of stego and cover image as each pixel based PBSM, and operand with LSB

A dual watermarking scheme for identity protection

A novel dual watermarking scheme with potential applications in identity protection, media integrity maintenance and copyright protection in both electronic and printed media is presented. The proposed watermarking scheme uses the owner’s signature and fingerprint as watermarks through which the ownership and validity of the media can be proven and kept intact. To begin with, the proposed watermarking scheme is implemented on continuous-tone/greyscale images, and later extended to images achieved via multitoning, an advanced version of halftoning-based printing. The proposed watermark embedding is robust and imperceptible. Experimental simulations and evaluations of the proposed method show excellent results from both objective and subjective view-points

Design of data validation solutions using high density 2D colored codes and a (2,2) xor-based color interference visual cryptography scheme

Tese (doutorado)—Universidade de Brasília, Faculdade de Tecnologia, Departamento de Engenharia Elétrica, 2018.A validação de dados nos sistemas de informação utiliza majoritariamente algoritmos criptográficos em sistemas que, geralmente, não utilizam materiais não eletrônicos como parte da infraestrutura do criptossistema. Nesse trabalho, foram desenvolvidos dois sistemas de armazenamento e recuperação de dados através da proposta de uma nova tecnologia de códigos de barra colorido bidimensional e de um novo esquema de criptografia visual. Os códigos de barras bidimensionais têm sido amplamente estudados, mas ainda continuam sem contar com um padrão que consiga transmitir alta quantidade de informação em pequenos espaços impressos. As aplicações desse modelo de transmissão tem como motivação a necessidade de armazenar (e recuperar) uma alta quantidade de informação em pequenas áreas impressas, como por exemplo, para utilização de dados criptográficos que sejam processados sem conexão e armazenados em pequenos espaços impressos, como os de caixas de remédios ou caixas de cigarros. O código de barras colorido 2D proposto nesse trabalho é chamado de High Density 2 Dimensional Code (HD2DC) e possui 8 diferentes tamanhos. O HD2DC permite a utilização de 5 ou 8 cores em cada tamanho e conta com o algoritmo de correção de erro Reed-Solomon com 3 diferentes níveis (10%, 20% e 30%). O HD2DC foi desenvolvido com o objetivo de ser um padrão de código de barras colorido 2D para operações de transmissão de grande quantidade de informações em pequenas ou médias áreas de impressão. Criptografia visual é uma técnica que cifra uma imagem secreta em duas ou mais imagens chave. A decodificação de qualquer esquema de criptografia visual depende do sistema visual humano e a maioria das propostas existentes consideram para a decodificação a utilização da sobreposição de duas ou mais lâminas físicas com n x n (n ≥ 2) pixels expandidos. O esquema de criptografia visual proposto nesse trabalho considera a utilização de duas imagens. A primeira é uma lâmina física feita por uma impressão colorida em Policloreto de Polivinila (PVC) transparente de 3 milímetros, enquanto que a segunda é uma imagem colorida apresentada na tela do visor de um smartphone. Ambas as imagens não geram expansão de pixels. A obtenção das melhores cores utilizadas nesse criptossistema foi realizada através de estudos físicos do comportamento da interferência de cor entre a tela do smartphone e a cor utilizada na impressão do PVC transparente. Essa nova proposta possui um alto nível de usabilidade para validação de dados em transações eletrônicas e conta com um custo muito baixo de implementação. Um sistema robusto de validação de dados é criado quando é combinada a criptografia visual proposta com o HD2DC. O HD2DC tem a capacidade de armazenar uma das imagens chave, no caso a que deve ser mostrada no visor do celular, essa arquitetura de codificação aumenta a percepção de segurança e explora a usabilidade do celular por meio da utilização da câmera e da tela como ferramentas para mostrar a imagem cifrada da criptografia visual.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Digital data validation generally requires that algorithms are ran into on cryptographic systems that, usually, do not use non-electronic devices as part of their information security infrastructure. This work presents two information storage and retrieval systems: a new colored two-dimensional barcode technology and a novel visual cryptography scheme. Two-dimensional barcodes have been a topic of research for several decades, but there is still no standard that stores and retrieves high amounts of data. Recently, new requirements have been imposed on applications that use 2D barcodes as a communication channel, such as the capability of storing information into a small printed area. This particular requirement is specially important for 2D barcodes that store cryptographic primitives to be processed off-line. This is the case of barcodes in products like cigarettes and medicines, which are used for data validation and product verification. The proposed 2D colored barcode is called High Density Two-Dimensional Code (HD2DC) and is currently one of the 2D barcodes with the highest data density. HD2DC can be generated in 8 different sizes, with 5 or 8 colors. To increase robustness, the system uses a Reed-Solomon error correction algorithm with 3 different levels: Low, Medium and High, which provide approximately 10%, 20% and 30% error correction, respectively. Visual cryptography (VC) is a technique that encodes the content of a secret image into two or more images, which are called shares. These shares are printed on transparencies and superimposed (requiring a good alignment) to reveal (visually) the original secret image, i.e. without requiring any computation. Current visual cryptography schemes use at least 2 shares (transparencies) as keys. With respect to the secret image size, most of these schemes produce a n x n (n ≥ 2) size expansion of the shares and the decoded image. The proposed Visual Cryptography scheme, on the other hand, uses two shares and does not require a size expansion. The first share is a colored film printed on a Polyvinyl Chloride (PVC) surface of 3 millimeters, while the second share is a colored image displayed on a smartphone or tablet. In this work, we performed a physical evaluation of the color interference properties of these two shares (the printed PVC transparency and the image displayed on the mobile device) to find the most adequate color space to be used in the proposed cryptosystem. We also propose a strong validation system combining our Xor-Based Visual Cryptography scheme with HD2DC. HD2DC has the capability of storing the share that is shown on the mobile device display. This encoding architecture enhances security perception and explores the mobile device usability, using its screen to display a Visual Cryptography share