Security on the Internet is essential to ensure the privacy of an individual. Today, Trans- port Layer Security (TLS) and certificates are used to ensure this. But certificates are not enough in order to maintain confidentiality and therefore a new concept, Certificate Trans- parency (CT), has been introduced. CT improves security by allowing the analysis of sus- picious certificates. Validation by CT uses public logs that can return Signed Certificate Timestamp (SCT), which is a promise returned by the log indicating that the certificate will be added to the log. A server may then deliver the SCT to a client in three different ways: X.509v3 extension, Online Certificate Status Protocol (OSCP) stapling and TLS extension. For further analysis, we have created a tool to collect data during TLS handshakes and data transfer, including byte information, the certificates themselves, SCT delivery method and especially timing information. From our dataset we see that most websites do not use CT and the ones that use CT almost only use X.509 extension to send their SCTs.

The sale of prepaid electricity is prevalent in South Africa due to the current economic, social, and political conditions. The system currently used for the distribution of tokens for prepaid electricity, CVS, has a design flaw that leads to many security vulnerabilities. The design flaw is that the security devices that generate the tokens are distributed in the field and operate independently of centralised control. This was done because of the limited communication infrastructure in South Africa 10 years ago, but is no longer necessary. An improvement to the system is suggested that removes the security vulnerabilities by making the system on-line. By employing the communication infrastructure that is available today to provide access to the security devices, the security devices can be located in a secure environment. Changing the mode of operation to on-line also has other advantages such as simplifying auditing and removing synchronisation problems. This improved system works by communicating on-line with a centralised server and database for every transaction that a customer makes. By doing this, all of the parties involved are kept up to date with the most recent transactions. There can no longer be financial discrepancies and the risk of all parties involved is thus reduced. It is no longer meaningful to steal the vending machines because they no longer have the ability to generate tokens independently. In order to implement such a system, however, there are many security aspects that need to be addressed, such as the confidentiality of the information within the system and proving that a transaction did occur between two specific parties. To this end, cryptographic functions and protocols are selected that meet the requirements of the system. Public key cryptography was found to be a necessary ingredient in making the system work effectively and efficiently. In order to use public key cryptography in the new system, Public Key Infrastructure is required to manage public keys and provide authentication services. A suitable system is developed and described that employs certificate authorities and X.509 certificates. The procedures that are required from each party are listed. A set of messages that is required for the functions of the system is given. For each message, the contents of the message is given, the parts of the message that must be encrypted are defined and the parts of the message that must be digitally signed are given. Finally, the security of the individual parts of the system is critically analysed to show that all of the design goals have been achieved. Particular attention is given to the authentication of parties involved in the communication. The security of the system as a whole is also evaluated with respect to the X.810 security framework and it is shown that the system is robust from a security perspective. The result of the research is a system that meets the required functionality to replace the existing system, and at the same time meets all of the security requirements. It is shown that the proposed system does not have the security flaws of the existing system and thus is more effective in its purpose of vending prepaid electricity. / Dissertation (MEng (Electronic))--University of Pretoria, 2007. / Electrical, Electronic and Computer Engineering / unrestricted

Certificate Transparency provides auditability to the widely used X.509 Public Key Infrastructure (PKIX) authentication in Transport Layer Security (TLS) protocol. Transparency logs issue signed promises of inclusions to be used together with certificates for authentication of TLS servers. Google Chrome enforces the use of Certificate Transparency for validation of Extended Validation (EV) certificates. This thesis proposes a methodology for asserting correct operation and presents a survey of active Logs. An experimental Monitor has been implemented as part of the thesis. Varying Log usage patterns and metadata about Log operation are presented, and Logs are categorized based on characteristics and usage. A case of mis-issuance by Symantec is presented to show the effectiveness of Certificate Transparency.

The Network Service Ochestrator (NSO) is a network automation system provided by Cisco that is used to automate large network changes with the ability to roll back in case of errors. It provides a rich northbound interface to communicate with the user and a southbound interface to orchestrate network devices securely. On these northbound and southbound interfaces, NSO supports NETCONF and RESTCONF, which is an IETF standard for network automation. NSO native implementation of NETCONF and RESTCONF lacks support for Public-Key Infrastructure (X.509) (PKIX) infrastructure and SSH and SSL/TLS as transport. Instead, Cisco suggests that customers use external relay agents such as PKIX-SSH for SSH and GNUTLS for TLS for NETCONF. The certificates and keys are saved on the hard drive and loaded for every connection via RESTCONF. This workaround solution provides authentication and authorization without audit logging within NSO. In this work, a native implementation of the X509 certification with PKIX infrastructure on SSH and SSL/TLS for NETCONF and RESTCONF is investigated. The project evaluates design alternatives with respect to security, computational complexity, maintainability, and user-friendliness, and concludes by highlighting the pros and cons of both native and workaround implementation. / Ciscos NSO är en nätverksorkestreringsplatform som används för att automatisera stora ändringar i nätverk med egenheten att ändringarna kan backas tillbaka om inte samtliga kan kan utföras. NSO tillhandahåller användare gränssnitt (northbound) för att säkert kommunicera (southbound) med nätverksenheterna. Gränssnitten stödjer de standardiserade protokollen Netconf och Restconf. Båda dessa protokoll saknar inbyggts stöd för PKIX över SSH, SSL och TSL. När detta önskas rekommenderar Cisco sina kunder att externa klienter som PKIX-SSH eller GNUTLS. När detta görs sparas certifikat och nyklar lokalt för varje Restconf koppel och ingen läggning av flödet kommer att ske i NSO. I detta arbete presenteras ett inbyggt stöd för X509 certifiering med PKIX för SSH, SSL, och TLS. Stödet kan användas för Netconf och Restconf. Olikheter mellan dagens tillgängliga stöd och det inbyggda stödet med avseende på säkerhet, komplexitet, underhållbarhet, och användarvänlighet jämförs. Avslutningsvis belyses för- respektive nackdelar med de olika implementateringarna.

La sécurité est un enjeu majeur des technologies numériques modernes. Avec le développement de l'Internet, les besoins de sécurité sont de plus en plus importants. Le développement d'applications Internet telles que le commerce électronique, les applications médicales ou la vidéoconférence, implique de nouveaux besoins comme, l'identification des entités communicantes, l'intégrité des messages échangés, la confidentialité de la transaction, l'authentification des entités, l'anonymat du propriétaire du certificat, l'habilitation des droits, la procuration, etc..<br /><br />Qu'il s'agisse de données médicales, fiscales ou bancaires, le besoin en sécurité est essentiel afin de crédibiliser le système, tout en respectant à la fois les besoins des utilisateurs et des applications. Cette sécurité a néanmoins un prix : celui de l'établissement de la confiance entre les partenaires en communication. La confiance des utilisateurs passe par la sécurisation des transactions, par exemple au moyen d'une procédure de certification, et la reconnaissance des signatures électroniques.<br /><br />Malgré la diversité des certificats numériques existants (certificat d'identité X.509, SPKI, certificat d'attributs, etc.), ils sont encore limités, génériques et répondent ainsi insuffisamment aux besoins spécifiques des applications électroniques et des utilisateurs. D'où la nécessité de spécifier une nouvelle approche pour la génération de certificats numériques répondant à ces exigences, légers, simplifiés et plus ouverts que ceux existants.<br /><br />Les travaux de recherche présentés dans cette thèse consistent à proposer une nouvelle approche pour la génération de certificats numériques pour contribuer aux services d'autorisation, puis à intégrer cette contribution au protocole d'attribution dynamique des adresses DHCP (Dynamic Host Configuration Protocol)afin de le renforcer.<br /><br />Cette thèse est constituée de deux parties.<br /><br />Dans la première partie, nous traitons les différents types de certificats existants ainsi que leurs limites. Nous proposons et spécifions une approche qui permet de garantir à l'application et à l'utilisateur la bonne mise en forme des informations dans le certificat et l'adéquation du contenu de leur certificat vis-à-vis de leurs besoins.<br />Ces certificats sont des certificats d'attributs spécifiés en XML, flexibles et respectant les besoins de l'application et la personnalisation de l'utilisateur durant la génération du certificat.<br />Pour chaque application, nous avons défini une grammaire DTD (Document Type Definition) pour préciser tous les champs dont l'application a besoin. L'idée principale est de stocker, sur le serveur, des DTDs c'est-à-dire, des fichiers contenant un certain nombre de paramètres correspondant aux données qui seront insérées dans le certificat d'attributs final. La génération de ces certificats d'attributs respecte la grammaire associée à<br />l'application. En effet, c'est grâce à celles-ci que l'administrateur personnalisera les certificats d'attributs que<br />l'utilisateur pourra demander. Ainsi, si le besoin d'un nouveau type de certificat d'attributs émane, il suffit de créer la DTD correspondant à la nouvelle application ajoutée.<br /><br />Pour satisfaire les besoins de l'utilisateur, l'E-IGP (Extension de l'Infrastructure de Gestion des Privilèges)permet à ce dernier de personnaliser sa demande de certificats d'attributs. C'est l'utilisateur qui précise les valeurs des paramètres de l'application, la date de validité de son certificat d'attributs, les rôles qu'il souhaite avoir ou les délégations qu'il souhaite fournir à quelqu'un suivant ces besoins. La mise en oeuvre de l'E-IGP a nécessité l'existence d'une Infrastructure de Gestion des Clefs, à laquelle l'E-IGP est rattaché.<br /><br />Pour prouver la faisabilité et l'efficacité de l'approche proposée, nous l'intégrons dans le fonctionnement du protocole DHCP. Destiné à faciliter le travail des administrateurs systèmes en automatisant l'attribution des adresses IP et les paramètres de configurations aux clients du réseau, le protocole DHCP souffre de nombreux problèmes de sécurité. Il ne supporte pas le mécanisme avec lequel les clients et les serveurs DHCP<br />s'authentifient. De plus, le protocole DHCP n'assure pas l'intégrité des données échangées, ni leur confidentialité et il ne possède aucun mécanisme de contrôle d'accès.<br /><br />La deuxième contribution majeure de cette thèse est la spécification et l'implémentation d'une extension du protocole DHCP, appelée E-DHCP (Extended Dynamic Host Configuration Protocol). E-DHCP présente une méthode d'authentification d'entités (client et serveur) DHCP et des contenus des messages DHCP. E-DHCP propose une nouvelle option DHCP. La technique utilisée par cette option est basée sur l'utilisation<br />d'algorithmes de clefs de chiffrement asymétrique, de certificats d'identité X.509 et de certificats d'attributs simplifiés spécifiés en XML, proposés dans la première contribution de cette thèse. L'idée principale de E-DHCP est d'adosser au serveur DHCP un serveur AA (Attribute Authority) d'un E-IGP pour former un nouveau serveur appelé serveur E-DHCP. Ce nouveau serveur crée un certificat d'attributs pour le client contenant l'adresse Internet attribuée dynamiquement. L'utilisation du certificat d'attributs confirme la possession du client de son adresse IP.

<p>In the area of computer network security, standardization work has been conducted for several years. However, the sub area of access control and authorization has so far been left out of major standardizing. </p><p>This thesis explores the ongoing standardization for access control and authorization. In addition, areas and techniques supporting access control are investigated. Access control in its basic forms is described to point out the building blocks that always have to be considered when an access policy is formulated. For readers previously unfamiliar with network security a number of basic concepts are presented. An overview of access control in public networks introduces new conditions and points out standards related to access control. None of the found standards fulfills all of our requirements at current date. The overview includes a comparison between competing products, which meet most of the stated conditions. </p><p>In parallel with this report a prototype was developed. The purpose of the prototype was to depict how access control could be administered and to show the critical steps in formulating an access policy.</p>

<p>This master thesis consists of three parts. The first part contains a summary of what is needed to understand a X.509 parser that I have created, a discussion concerning the technical problems I encountered during the programming of this parser and a discussion concerning the final version of the parser. The second part concerns a comparison I made between the X.509 parser I created and a X.509 parser created"automatically"by a compiler. I tested static memory, allocation of memory during runtime and utilization of the CPU for both my parser (MP) and the parser that had a basic structure constructed by a compiler (OAP). I discuss changes in the parsers involved to make the comparison fair to OAP, the results from the tests and when circumstances such as time and non-standard content in the project make one way of constructing a X.509 parser better than the other way. The last part concerns a WTLS parser (a simpler kind of X.509 parser), which I created.</p>

In the area of computer network security, standardization work has been conducted for several years. However, the sub area of access control and authorization has so far been left out of major standardizing. This thesis explores the ongoing standardization for access control and authorization. In addition, areas and techniques supporting access control are investigated. Access control in its basic forms is described to point out the building blocks that always have to be considered when an access policy is formulated. For readers previously unfamiliar with network security a number of basic concepts are presented. An overview of access control in public networks introduces new conditions and points out standards related to access control. None of the found standards fulfills all of our requirements at current date. The overview includes a comparison between competing products, which meet most of the stated conditions. In parallel with this report a prototype was developed. The purpose of the prototype was to depict how access control could be administered and to show the critical steps in formulating an access policy.

This master thesis consists of three parts. The first part contains a summary of what is needed to understand a X.509 parser that I have created, a discussion concerning the technical problems I encountered during the programming of this parser and a discussion concerning the final version of the parser. The second part concerns a comparison I made between the X.509 parser I created and a X.509 parser created"automatically"by a compiler. I tested static memory, allocation of memory during runtime and utilization of the CPU for both my parser (MP) and the parser that had a basic structure constructed by a compiler (OAP). I discuss changes in the parsers involved to make the comparison fair to OAP, the results from the tests and when circumstances such as time and non-standard content in the project make one way of constructing a X.509 parser better than the other way. The last part concerns a WTLS parser (a simpler kind of X.509 parser), which I created.

Certificates are the foundation of secure communication over the internet as of today. While certificates can be issued with long validity periods, there is always a risk of having them compromised during their lifetime. A good practice is therefore to use shorter validity periods. However, this limits the certificate lifetime and gives less flexibility in the timing of certificate replacements. In this thesis, we use publicly available network logs from Rapid7's Project Sonar to provide an overview of the current state of certificate usage behavior. Specifically, we look at the Let's Encrypt mass revocation event in March 2020, where millions of certificates were revoked with just five days notice. In general, we show how this kind of datasets can be used, and as a deeper exploration we analyze certificate validity, lifetime and use of certificates with overlapping validity periods, as well as discuss how our findings relate to industry standard and current security trends. Specifically, we isolate automated certificate services such as Let's Encrypt and cPanel to see how their certificates differ in characteristics from other certificates in general. Based on our findings, we propose a set of rules to help improve the trust in certificate usage and strengthen security online, introducing an Always secure policy aligning certificate validity with revocation time limits in order to replace revocation requirements and overcoming the fact that mobile devices today ignore this very important security feature. To round things off, we provide some ideas for further research based on our findings and what we see possible with datasets such as the one researched in this thesis.