This Spotlight introduces some classical information-security approaches, e.g., steganography, watermarking, and digital cryptographic methods. It provides an overview of optical encryption from the perspective of image (both 2-D and 3-D) and optical-information processing. Both experimental and synthesized results (images) are provided in the text for illustration. Wherever possible (space permitting), background information is provided, although some knowledge of advanced mathematics and image processing, and familiarity with standard scientific computing languages, is needed for complete comprehension.
Generalized Phase Contrast elevates the phase contrast technique not only to improve phase imaging but also to cross over and interface with diverse and seemingly disparate fields of contemporary optics and photonics. This book presents a comprehensive introduction to the Generalized Phase Contrast (GPC) method including an overview of the range of current and potential applications of GPC in wavefront sensing and phase imaging, structured laser illumination and image projection, optical trapping and manipulation, and optical encryption and decryption. The GPC method goes further than the restrictive assumptions of conventional Zernike phase contrast analysis and achieves an expanded range of validity beyond weak phase perturbations. The generalized analysis yields design criteria for tuning experimental parameters to achieve optimal performance in terms of accuracy, fidelity and light efficiency. Optimization can address practical issues, such as finding an optimal spatial filter for the chosen application, and can even enable a Reverse Phase Contrast mode where intensity patterns are converted into a phase modulation.
Advanced technologies such as artificial intelligence, big data, cloud computing, and the Internet of Things have changed the digital landscape, providing many new and exciting opportunities. However, they also provide ever-shifting gateways for information theft or misuse. Staying ahead requires the development of innovative and responsive security measures, and recent advances in optical technology have positioned it as a promising alternative to digital cryptography. Optical Cryptosystems introduces the subject of optical cryptography and provides up-to-date coverage of optical security schemes. Optical principles, approaches, and algorithms are discussed as well as applications, including image/data encryption-decryption, watermarking, image/data hiding, and authentication verification. This book also includes MATLAB(R) codes, enabling students and research professionals to carry out exercises and develop newer methods of image/data security and authentication.
Code-division multiple access (CDMA) technology has been widely adopted in cell phones. Its astonishing success has led many to evaluate the promise of this technology for optical networks. This field has come to be known as Optical CDMA (OCDMA). Surveying the field from its infancy to the current state, Optical Code Division Multiple Access: Fundamentals and Applications offers the first comprehensive treatment of OCDMA from technology to systems. The book opens with a historical perspective, demonstrating the growth and development of the technologies that would eventually evolve into today's optical networks. Building on this background, the discussion moves to coherent and incoherent optical CDMA coding techniques and performance analysis of these codes in fiber optic transmission systems. Individual chapters provide detailed examinations of fiber Bragg grating (FBG) technology including theory, design, and applications; coherent OCDMA systems; and incoherent OCDMA systems. Turning to implementation, the book includes hybrid multiplexing techniques along with system examples and conversion techniques to connect networks that use different multiplexing platforms, state-of-the-art integration technologies, OCDMA network security issues, and OCDMA network architectures and applications, including a look at possible future directions. Featuring contributions from a team of international experts led by a pioneer in optical technology, Optical Code Division Multiple Access: Fundamentals and Applications places the concepts, techniques, and technologies in clear focus for anyone working to build next-generation optical networks.
Presenting encryption algorithms with diverse characteristics, Image Encryption: A Communication Perspective examines image encryption algorithms for the purpose of secure wireless communication. It considers two directions for image encryption: permutation-based approaches and substitution-based approaches. Covering the spectrum of image encryption principles and techniques, the book compares image encryption with permutation- and diffusion-based approaches. It explores number theory-based encryption algorithms such as the Data Encryption Standard, the Advanced Encryption Standard, and the RC6 algorithms. It not only details the strength of various encryption algorithms, but also describes their ability to work within the limitations of wireless communication systems. Since some ciphers were not designed for image encryption, the book explains how to modify these ciphers to work for image encryption. It also provides instruction on how to search for other approaches suitable for this task. To make this work comprehensive, the authors explore communication concepts concentrating on the orthogonal frequency division multiplexing (OFDM) system and present a simplified model for the OFDM communication system with its different implementations. Complete with simulation experiments and MATLAB® codes for most of the simulation experiments, this book will help you gain the understanding required to select the encryption method that best fulfills your application requirements.
Optical and photonic systems and devices have significant potential for homeland security. "Optical Imaging Sensors and Systems for Homeland Security Applications" presents original and significant technical contributions from leaders of industry, government, and academia in the field of optical and photonic sensors, systems and devices for detection, identification, prevention, sensing, security, verification and anti-counterfeiting. The chapters have recent and technically significant results, ample illustrations, figures, and key references. This book is intended for engineers and scientists in the relevant fields, graduate students, industry managers, university professors, government managers, and policy makers.
For every opportunity presented by the information age, there is an opening to invade the privacy and threaten the security of the nation, U.S. businesses, and citizens in their private lives. The more information that is transmitted in computer-readable form, the more vulnerable we become to automated spying. It's been estimated that some 10 billion words of computer-readable data can be searched for as little as $1. Rival companies can glean proprietary secrets . . . anti-U.S. terrorists can research targets . . . network hackers can do anything from charging purchases on someone else's credit card to accessing military installations. With patience and persistence, numerous pieces of data can be assembled into a revealing mosaic. Cryptography's Role in Securing the Information Society addresses the urgent need for a strong national policy on cryptography that promotes and encourages the widespread use of this powerful tool for protecting of the information interests of individuals, businesses, and the nation as a whole, while respecting legitimate national needs of law enforcement and intelligence for national security and foreign policy purposes. This book presents a comprehensive examination of cryptographyâ€"the representation of messages in codeâ€"and its transformation from a national security tool to a key component of the global information superhighway. The committee enlarges the scope of policy options and offers specific conclusions and recommendations for decision makers. Cryptography's Role in Securing the Information Society explores how all of us are affected by information security issues: private companies and businesses; law enforcement and other agencies; people in their private lives. This volume takes a realistic look at what cryptography can and cannot do and how its development has been shaped by the forces of supply and demand. How can a business ensure that employees use encryption to protect proprietary data but not to conceal illegal actions? Is encryption of voice traffic a serious threat to legitimate law enforcement wiretaps? What is the systemic threat to the nation's information infrastructure? These and other thought-provoking questions are explored. Cryptography's Role in Securing the Information Society provides a detailed review of the Escrowed Encryption Standard (known informally as the Clipper chip proposal), a federal cryptography standard for telephony promulgated in 1994 that raised nationwide controversy over its "Big Brother" implications. The committee examines the strategy of export control over cryptography: although this tool has been used for years in support of national security, it is increasingly criticized by the vendors who are subject to federal export regulation. The book also examines other less well known but nevertheless critical issues in national cryptography policy such as digital telephony and the interplay between international and national issues. The themes of Cryptography's Role in Securing the Information Society are illustrated throughout with many examplesâ€"some alarming and all instructiveâ€"from the worlds of government and business as well as the international network of hackers. This book will be of critical importance to everyone concerned about electronic security: policymakers, regulators, attorneys, security officials, law enforcement agents, business leaders, information managers, program developers, privacy advocates, and Internet users.
Nonlinear behavior of light such as chaos can be observed during propagation of a laser beam inside the microring resonator (MRR) systems. This Brief highlights the design of a system of MRRs to generate a series of logic codes. An optical soliton is used to generate an entangled photon. The ultra-short soliton pulses provide the required communication signals to generate a pair of polarization entangled photons required for quantum keys. In the frequency domain, MRRs can be used to generate optical millimetre-wave solitons with a broadband frequency of 0–100 GHz. The soliton signals are multiplexed and modulated with the logic codes to transmit the data via a network system. The soliton carriers play critical roles to transmit the data via an optical communication link and provide many applications in secured optical communications. Therefore, transmission of data information can be performed via a communication network using soliton pulse carriers. A system known as optical multiplexer can be used to increase the channel capacity and security of the signals.
This book addresses the fundamental concepts in the theory and practice of visual cryptography. The design, construction, analysis, and application of visual cryptography schemes (VCSs) are discussed in detail. Original, cutting-edge research is presented on probabilistic, size invariant, threshold, concolorous, and cheating immune VCS. This updated second edition has also been expanded with new content on braille and 2D barcode authentication of visual cryptography shares. Features: contains review exercises at the end of each chapter, as well as a helpful glossary; examines various common problems in visual cryptography, including the alignment, flipping, cheating, distortion, and thin line problems; reviews a range of VCSs, including XOR-based visual cryptography and security enriched VCS; describes different methods for presenting color content using visual cryptographic techniques; covers such applications of visual cryptography as watermarking, resolution variant VCS, and multiple resolution VCS.
