L'authentification homme-machine est une problématique largement développée pour les télécommunications. Une authentification dans le sens "machine-homme" permettra d'assurer l'utilisateur humain assermenté du fonctionnement intègre d'une machine lors, par exemple, d'une session de vote électronique ou d'une vérification d'objet en traçabilité sécurisée. Cette thèse se focalise sur la traçabilité sécurisée sans accès (systématique) à un canal de communication. Nous décrivons différentes techniques d'authentification de produits manufacturés en nous concentrant sur une méthode de caractérisation de motifs imprimés. Pour effectivement authentifier un objet, nous montrons qu'un agent vérifieur doit s'assurer de l'intégrité du tiers et du système électronique utilisée pour la vérification. Cependant l'authenticité du système électronique lui-même reste à vérifier. La question que nous adressons alors est la suivante : comment un être humain peut-il se convaincre de l'intégrité et de l'authenticité d'un système embarqué dans un mode hors ligne ? Nous définissons deux familles de solutions. Dans la première, l'utilisateur fait appel, pour les calculs, à un dispositif auxiliaire tandis que dans la seconde l'utilisateur ne fait usage que d'un papier et d'un crayon. Pour chacune des deux familles, nous proposons un protocole d'authentification d'un système embarqué dont la puce, typiquement un FPGA ou un microcontrôleur, dépend de la configuration ou de la programmation d'une mémoire RAM / "Human-to-Machine" authentication is widely developed for modern telecommunications. A "Machine-to-Human" authentication will ensure the trusted human user about the integrity of the machine, for example during an electronic voting session or object verification in secure traceability. This work is focused on secure traceability without any systematic access to a communication network. We depict different technics for goods authentication and we focus on a method based on the characterization of printed patterns. To completely authenticate an object, we show that a human verifier has to be confident in the integrity of the third party and the electronic system involved in the verification phase. However, the authenticity of the electronic system itself has also to be verified. We address here the following question : how a human being can convince himself about the integrity and the authenticity of an embedded system in an off-line environment ? We propose two groups of solutions. In the first one, an auxiliary electronic device is used to perform computing operations. In the second one, the human capability (memory and computational abilities) is exploited. In each group, we propose a protocol to authenticate embedded systems for which the chip (typically an FPGA (Field Programmable Gate Array) or a microcontroller) is initialized according to the configuration or programming of its RAM memory

This thesis addresses authenticity and integrity of medical images using watermarking. Hospital Information Systems (HIS), Radiology Information Systems (RIS) and Picture Archiving and Communication Systems (P ACS) now form the information infrastructure for today's healthcare as these provide new ways to store, access and distribute medical data that also involve some security risk. Watermarking can be seen as an additional tool for security measures. As the medical tradition is very strict with the quality of biomedical images, the watermarking method must be reversible or if not, region of Interest (ROI) needs to be defined and left intact. Watermarking should also serve as an integrity control and should be able to authenticate the medical image. Three watermarking techniques were proposed. First, Strict Authentication Watermarking (SAW) embeds the digital signature of the image in the ROI and the image can be reverted back to its original value bit by bit if required. Second, Strict Authentication Watermarking with JPEG Compression (SAW-JPEG) uses the same principal as SAW, but is able to survive some degree of JPEG compression. Third, Authentication Watermarking with Tamper Detection and Recovery (AW-TDR) is able to localise tampering, whilst simultaneously reconstructing the original image.

In the thesis are described and implemented 5 methods (some with their own proposal) of multifactor authentication in web application environment. The results of the work is the web application and individual authentication methods (which are attached separately) for use in your own web application.

Static authentication, where user identity is checked once at login time, can be circumvented no matter how strong the authentication mechanism is. Through attacks such as man-in-the-middle and its variants, an authenticated session can be hijacked later after the initial login process has been completed. In the last decade, continuous authentication (CA) using biometrics has emerged as a possible remedy against session hijacking. CA consists of testing the authenticity of the user repeatedly throughout the authenticated session as data becomes available. CA is expected to be carried out unobtrusively, due to its repetitive nature, which means that the authentication information must be collectible without any active involvement of the user and without using any special purpose hardware devices (e.g. biometric readers). Stylometry analysis, which consists of checking whether a target document was written or not by a specific individual, could potentially be used for CA. Although stylometric techniques can achieve high accuracy rates for long documents, it is still challenging to identify an author for short documents, in particular when dealing with large author populations. In this dissertation, we propose a new framework for continuous authentication using authorship verification based on the writing style. Authorship verification can be checked using stylometric techniques through the analysis of linguistic styles and writing characteristics of the authors. Different from traditional authorship verification that focuses on long texts, we tackle the use of short messages. Shorter authentication delay (i.e. smaller data sample) is essential to reduce the window size of the re-authentication period in CA. We validate our method using different block sizes, including 140, 280, and 500 characters, and investigate shallow and deep learning architectures for machine learning classification. Experimental evaluation of the proposed authorship verification approach based on the Enron emails dataset with 76 authors yields an Equal Error Rate (EER) of 8.21% and Twitter dataset with 100 authors yields an EER of 10.08%. The evaluation of the approach using relatively smaller forgery samples with 10 authors yields an EER of 5.48%. / Graduate

International Telemetering Conference Proceedings / October 25-28, 1999 / Riviera Hotel and Convention Center, Las Vegas, Nevada / The arms control verification activity is executed between countries, so various telemetry data will be remote-transmitted in the public signal channel and can be easily tampered. In order to secure this data’s authenticity and integrality, the paper has established a Multi-layer Data Authentication Protocol (MDAP) in which the key cryptographic technologies are digital signature and authentication. Meanwhile, overall evaluations of MDAP have been presented. We proved the MDAP is secure.

International Telemetering Conference Proceedings / October 21, 2002 / Town & Country Hotel and Conference Center, San Diego, California / Next generation flight termination systems (FTSs) will use digital technologies to verify the authenticity of range safety commands by command receiver-decoders located on each vehicle. This paper will discuss the general principles behind simplex message authentication using a block encryption cipher, and presents examples for demonstration.

In this thesis we study how hash chains and other hash structures can be used in various cryptographic applications. In particular we focus on the applications of entity authentication, signatures and key establishment. We study recursive application of hash functions to create hash chains, hash trees and other hash structures. We collate all these to form a catalogue of structures that we apply to various cryptographic applications. We study existing work on authentication and create many entity authentication schemes based on structures from our catalogue. We present a novel algorithm to find efficient signature schemes from any given hash structure. We study some suggestions for suitable hash structures and define a particular scalable hash structure complete with a simple message to signature map that is the most efficient such scheme of which we know. We explore k-time signature schemes and identify two new properties, which we call perforated and porous. We look at the application of hash structures to key establishment schemes. We compare the existing schemes and make improvements on many. We present a new key establishment scheme, and show a link between certain k-time signatures and certain key establishment schemes. We look at the other applications of hash structures, and suggest areas in which our catalogue could be used for further development.

代理者（Agent）是一個自主性的軟體程式，可以幫助代表人類在網際網路上從事各種的電子化服務（E-Service）。由於目前多代理者系統缺少了安全管理的機制，以致於目前為止代理者代表人類在網上從事活動的行為還不被大家接受。因此，我們提出了一套以代理者為導向的公鑰匙架構（Agent-Oriented Public Key Infrastructure, APKI），各式各樣的數位憑證被產生、儲存、註銷及驗證，以滿足不同存取控制的需求。例如，代理者的認證是以代理者身份憑證為基礎，而授權的部分則以授權憑證或屬性憑證來做驗證。透過這些數位憑證，我們可以在虛擬網路上的代理者之間建立一條信任路徑，一個安全的電子化服務的實際應用範例將會以此架構實作及呈現出來，以驗證我們所提架構的可行性。 / Agent is autonomous software that mediates e-service for human on the Internet. The acceptance of agent-mediated e-service (AMES) is very slow for the lacking of security management infrastructure for multi-agent system. Therefore we proposed an agent-oriented public key infrastructure (APKI) for multi-agent e-service. In this APKI, a taxonomy of digital certificates are generated, stored, verified, and revoked to satisfy different access and delegation control purposes. Agent identity certificate was designed for agent’s authentication whereas attributed and agent authorization certificates were proposed for agent’s authorization and delegation. Using these digital certificates, we establish agent trust relationships on the cyberspace. A trusted agent-mediated e-service scenario will be shown to demonstrate the feasibility of our APKI.

Multi-touch tablets allow users to interact with computers through intuitive, natural gestures and direct manipulation of digital objects. One advantage of these devices is that they can offer a large, collaborative space where several users can work on a task at the same time. However the lack of privacy in these situations makes standard password-based authentication easily compromised. This work presents a new gesture-based authentication system based on users' unique signature of touch motion. This technique has two key features. First, at each step in authentication the system prompts the user to make a specific gesture selected to maximize the expected long-term information gain. Second, each gesture is integrated using a hierarchical probabilistic model, allowing the system to accept or reject a user after a variable number of gestures. This touch-based approach would allow the user to accurately authenticate without the need to cover their hand or look over their shoulder. This method has been tested using a set of samples collected under real-world conditions in a business office, with a touch tablet that was used on a near daily basis by users familiar with the device. Despite the lack of sophisticated, high-precision equipment, the system is able to achieve high user recognition accuracy with relatively few gestures, demonstrating that human touch patterns have a distinctive signature" that can be used as a powerful biometric measure for user recognition and personalization.

This essay presents an emerging conception of truth and shows how it appropriates Herman Dooyeweerd’s conception. First I compare my “critical hermeneutics” with other reformational models of critique. Then I propose to think of truth as a dynamic correlation between (1) human fidelity to societal principles and (2) a life-giving disclosure of society. This conception recontextualizes the notion of propositional truth, and it links questions of intersubjective validity with Dooyeweerd’s emphasis on “standing in the truth.” While abandoning his idea of transcendent truth, I seek to preserve the holism and normativity of Dooyeweerd’s radical conception.