Laser speckle photography for surface tampering detection

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2012.Cataloged from PDF version of thesis.Includes bibliographical references (p. 59-61).It is often desirable to detect whether a surface has been touched, even when the changes made to that surface are too subtle to see in a pair of before and after images. To address this challenge, we introduce a new imaging technique that combines computational photography and laser speckle imaging. Without requiring controlled laboratory conditions, our method is able to detect surface changes that would be indistinguishable in regular photographs. It is also mobile and does not need to be present at the time of contact with the surface, making it well suited for applications where the surface of interest cannot be constantly monitored. Our approach takes advantage of the fact that tiny surface deformations cause phase changes in reflected coherent light which alter the speckle pattern visible under laser illumination. We take before and after images of the surface under laser light and can detect subtle contact by correlating the speckle patterns in these images. A key challenge we address is that speckle imaging is very sensitive to the location of the camera, so removing and reintroducing the camera requires high-accuracy viewpoint alignment. To this end, we use a combination of computational rephotography and correlation analysis of the speckle pattern as a function of camera translation. Our technique provides a reliable way of detecting subtle surface contact at a level that was previously only possible under laboratory conditions. With our system, the detection of these subtle surface changes can now be brought into the wild.by YiChang Shih.S.M

Implementação fotónica de funções fisicamente não clonáveis

This dissertation aimed to study and develop optical Physically Unclonable Functions, which are physical devices characterized by having random intrinsic variations, thus being eligible towards high security systems due to their unclonability, uniqueness and randomness. With the rapid expansion of technologies such as Internet of Things and the concerns around counterfeited goods, secure and resilient cryptographic systems are in high demand. Moreover the development of digital ecosystems, mobile applications towards transactions now require fast and reliable algorithms to generate secure cryptographic keys. The statistical nature of speckle-based imaging creates an opportunity for these cryptographic key generators to arise. In the scope of this work, three different tokens were implemented as physically unclonable devices: tracing paper, plastic optical fiber and an organic-inorganic hybrid. These objects were subjected to a visible light laser stimulus and produced a speckle pattern which was then used to retrieve the cryptographic key associated to each of the materials. The methodology deployed in this work features the use of a Discrete Cosine Transform to enable a low-cost and semi-compact 128-bit key encryption channel. Furthermore, the authentication protocol required the analysis of multiple responses from different samples, establishing an optimal decision threshold level that maximized the robustness and minimized the fallibility of the system. The attained 128-bit encryption system performed, across all the samples, bellow the error probability detection limit of 10-12, showing its potential as a cryptographic key generator.Nesta dissertação pretende-se estudar e desenvolver Funções Fisicamente Não Clonáveis, dispositivos caracterizados por terem variações aleatórias intrínsecas, sendo, portanto, elegíveis para sistemas de alta segurança devido à sua impossibilidade de clonagem, unicidade e aleatoriedade. Com a rápida expansão de tecnologias como a Internet das Coisas e as preocupações com produtos falsificados, os sistemas criptográficos seguros e resilientes são altamente requisitados. Além disso, o desenvolvimento de ecossistemas digitais e de aplicações móveis para transações comerciais requerem algoritmos rápidos e seguros de geração de chaves criptográficas. A natureza estatística das imagens baseadas no speckle cria uma oportunidade para o aparecimento desses geradores de chaves criptográficas. No contexto deste trabalho, três dispositivos diferentes foram implementados como funções fisicamente não clonáveis, nomeadamente, papel vegetal, fibra ótica de plástico e um híbrido orgânico-inorgânico. Estes objetos foram submetidos a um estímulo de luz coerente na região espectral visível e produziram um padrão de speckle o qual foi utilizado para recuperar a chave criptográfica associada a cada um dos materiais. A metodologia implementada neste trabalho incorpora a Transformada Discreta de Cosseno, o que possibilita a criação de um sistema criptográfico de 128 bits caracterizado por ser semi-compacto e de baixo custo. O protocolo de autenticação exigiu a análise de múltiplas respostas de diferentes Physically Unclonable Functions (PUFs), o que permitiu estabelecer um nível de limite de decisão ótimo de forma a maximizar a robustez e minimizar a probabilidade de erro por parte do sistema. O sistema de encriptação de 128 bits atingiu valores de probabilidade de erro abaixo do limite de deteção, 10-12, para todas as amostras, mostrando o seu potencial como gerador de chaves criptográficas.Mestrado em Engenharia Físic

NASA patent abstracts bibliography: A continuing bibliography. Section 1: Abstracts (supplement 35)

Abstracts are provided for 58 patents and patent applications entered into the NASA scientific and technical information systems during the period January 1989 through June 1989. Each entry consists of a citation, an abstract, and in most cases, a key illustration selected from the patent or patent application

Three-dimensional geometry characterization using structured light fields

Tese de doutoramento. Engenharia Mecânica. Faculdade de Engenharia. Universidade do Porto. 200

Machine Learning Attacks on Optical Physical Unclonable Functions

Traditional security algorithms for authentication and encryption rely heavily on the digital storage of secret information (e.g. cryptographic key), which is vulnerable to copying and destruction. An attractive alternative to digital storage is the storage of this secret information in the intrinsic, unpredictable, and non-reproducible features of a physical object. Such devices are termed physical unclonable functions (PUFs), and recent research proves that PUFs can resolve the vulnerabilities associated with digital key storage while otherwise maintaining the same level of security as traditional methods. Modern cryptographic algorithms rest on the shoulders of this one-way principle in certain mathematical algorithms (e.g. RSA or Rabin functions). However, a key difference between PUFs and traditional one-way algorithms is that conventional algorithms can be duplicated. Here, we investigate a silicon photonic PUF a novel cryptographic device based on ultrafast and nonlinear optical interactions within an integrated silicon photonic cavity. This work reviews the important properties of this device including high complexity of light interaction with the material, unpredictability of the response and ultrafast generation of private information. We further explore the resistance of silicon photonic PUFs against numerical modeling attacks and demonstrate the influence of cavity’s inherent nonlinear optical properties on the success of such attacks. Finally, we demonstrate encrypted data storage and compare the results of decryption using a genuine silicon PUF device the “clone” generated by the numerical algorithm. Finally, we provide similar analysis of modeling attacks on another well-known type of optical PUF, called the optical scattering PUF (OSPUF). While not as compatible with integration as the silicon photonic PUF, the OSPUF system is known to be extremely strong and resistant to adversarial attacks. By attacking a simulated model of OSPUF, we attempt to present the underlying reasons behind the strong security of this given device and how this security scales with the OSPUFs physical parameters

Digital watermarking and novel security devices

EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Looking towards the future: the changing nature of intrusive surveillance and technical attacks against high-profile targets

In this thesis a novel Bayesian model is developed that is capable of predicting the probability of a range of eavesdropping techniques deployed, given an attacker's capability, opportunity and intent. Whilst limited attention by academia has focused on the cold war activities of Soviet bloc and Western allies' bugging of embassies, even less attention has been paid to the changing nature of the technology used for these eavesdropping events. This thesis makes four contributions: through the analysis of technical eavesdropping events over the last century, technological innovation is shown to have enriched the eavesdropping opportunities for a range of capabilities. The entry barrier for effective eavesdropping is lowered, while for the well resourced eavesdropper, the requirement for close access has been replaced by remote access opportunities. A new way to consider eavesdropping methods is presented through the expert elicitation of capability and opportunity requirements for a range of present-day eavesdropping techniques. Eavesdropping technology is shown to have life-cycle stages with the technology exploited by different capabilities at different times. Three case studies illustrate that yesterday’s secretive government method becomes today’s commodity. The significance of the egress transmission path is considered too. Finally, by using the expert elicitation information derived for capability, opportunity and life-cycle position, for a range of eavesdropping techniques, it is shown that it is possible to predict the probability of particular eavesdropping techniques being deployed. This novel Bayesian inferencing model enables scenarios with incomplete, uncertain or missing detail to be considered. The model is validated against the previously collated historic eavesdropping events. The development of this concept may be scaled with additional eavesdropping techniques to form the basis of a tool for security professionals or risk managers wishing to define eavesdropping threat advice or create eavesdropping policies based on the rigour of this technological study.Open Acces

A report on CVPR2012

CVPR2012 報告.修正版.A report on CVPR2012. A revised version.電子情報通信学会パターン認識・メディア理解研究会,2012/6/29 補足資

Reducing Inherent Deviations in Galvanometer Scanning Systems for Large Area Processing

Galvanometer laser machining is a well-established laser machining technique in which the laser beam is positioned on a working field by means of mirrors mounted in galvanometers. Nonetheless, new applications make necessary the development of innovative techniques for increasing the performance of such systems. Aside all the advantages of this technique like given resolution, repeatability and velocity, a limited working area is an important drawback. In this thesis work, the limitations of different state-of-the-art schemes for increasing the working field of galvanometer laser machining systems are examined. The necessity of a new strategy for reducing present deviations introducing a vision system is established. The construction of an error vector and calculation of coordinate’s transformations to improve precision are presented. In this work, the “Arithmetic mean transformation”, “individual correction transformation”, “iterative inverse distance weighting transformation” and a stitching approach denominated “Auto-stitching” are presented and demonstrated as methods for reducing inherent deviations in galvanometer scanning systems for large area processing

The technological translation from Industry 4.0 to Precision Agriculture: adoption and perception of Italian farmers

Purpose: This research aims to identify the rate of knowledge, adoption and perceptions of Italian farmers towards Precision Agriculture technologies. Methodology: An online survey was carried out, using the Snowball sampling method, among 755 Italian farmers and involving the main Italian trade associations. Findings: The findings showed that among Italian farmers the technologies related to Monitoring appear to be the best known, adopted and perceived as the most useful; followed by technologies related to Automation and IoT. Managerial implications: Considering the results that emerged from this research, it seems necessary to undertake models of training development paths so that farmers can deepen the themes of technological integration with an orientation towards sustainability. Research limitations: The present research, not being able to be considered exhaustive for the understanding of the phenomenon, aims to be the starting point for future research aimed at a further analysis on the models of diffusion and technological integration. Originality: The models of technological integration for agricultural cultivation techniques are constantly evolving. Through the analysis of knowledge, use and perception of farmers it could be possible to detect new models for the diffusion of technology