Security of ECQV-Certified ECDSA Against Passive Adversaries

We show that the elliptic curve Qu-Vanstone implicit certificate scheme (ECQV), when composed with the Elliptic Curve Digital Signature Algorithm (ECDSA), is secure against passive adversaries under the combined assumption of the random oracle model and the generic group model,---if the ECQV certificate itself is excluded from the signable message space, because of an attack of Kravitz. In contrast, we detail an attack on the composition of another implicit certificate scheme, proposed by Pintsov and Vanstone for Optimal Mail Certificates (OMC), and ECDSA. This composition attack forges an implicitly certified ECDSA signature, and is passive in the sense of needing no interaction with the signer or the certification authority. (Pintsov and Vanstone did not propose combining OMC with ECDSA.

Proposal and evaluation of authentication protocols for Smart Grid networks

Dissertação (mestrado)—Universidade de Brasília, Faculdade de Tecnologia, Departamento de Engenharia Elétrica, 2018.Uma rede Smart Grid (ou rede elétrica inteligente) representa a evolução das redes elétricas tradicionais, tornada possível graças à integração das tecnologias da informação e das comunicações com a infraestrutura elétrica. Esta integração propicia o surgimento de novos serviços, tornando a rede elétrica mais eficiente, gerando também novos desafios a serem atendidos, dentre eles a segurança do sistema. A rede SG deve garantir a confiabilidade, a integridade e a privacidade dos dados armazenados ou em transito pelo sistema, o que leva à necessidade de autenticação e controle de acesso, obrigando a todo usuário ou dispositivo a se autenticar e a realizar somente operações autorizadas. A autenticação de usuários e dispositivos é um processo muito importante para a rede SG, e os protocolos usados para esse fim devem ser capazes de proteção contra possiveis ataques (por exemplo, Man-in-the-Middle - MITM, repetição, Denegação de Serviço - DoS). Por outro lado, a autorização é tratada em conjunto com a autenticação e relacionada com as politicas de controle de acesso do sistema. Uma parte essencial para criar os protocolos de autenticação seguros envolve os esquemas de ciframento. O uso de um ou a combinação de vários esquemas afeta diretamente o desempenho do protocolo. Cada dia novos esquemas são propostos, e seu emprego nos protocolos de autenticação melhora o desempenho do sistema em comparação aos protocolos já propostos no mesmo cenário. Neste trabalho são propostos 3 (três) protocolos de autenticação seguros e de custo adequado para os cenários descritos a seguir: - Autenticação dos empregados das empresas de fornecimento de energia que procuram acesso ao sistema de forma remota; - Autenticação de Smart Meters numa Infraestrutura de medição avançada (AMI, do inglês Advanced Metering Infrastructure) baseada em nuvem computacional; e - Autenticação de veículos elétricos em uma rede V2G (do inglês, Vehicle-to-Grid). Cada um dos cenários tem caraterísticas particulares que são refletidas no projeto dos protocolos propostos. Além disso, todos os protocolos propostos neste trabalho garantem a autenticação mutua entre todas as entidades e a proteção da privacidade, confidencialidade e integridade dos dados do sistema. Uma comparação dos custos de comunicação e computação é apresentada entre os protocolos propostos neste trabalho e protocolos desenvolvidos por outros autores para cada um dos cenários. Os resultados das comparações mostram que os protocolos propostos neste trabalho têm, na maioria dos casos, o melhor desempenho computacional e de comunicações, sendo assim uma ótima escolha para a sua implementação nas redes SG. A validação formal dos protocolos propostos por meio da ferramenta AVISPA é realizada, permitindo verificar o atendimento a requisitos de segurança.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES).A Smart Grid network (or inteligent electrical network) represents the evolution of traditional electrical networks, made possible due to the integration of information and communication technologies with the electrical power grid. This integration generates new services and improves the efficiency of the electrical power grid, while new challenges appear and must be solved, including the security of the system. The SG network must assure reliability, integrity and privacy of the data stored or in trnsit in the system, leading to the need for authentication and access control, thus all users and devices must authenticate and accomplish only authorized operations. The authentication of users and devices is a very important process for the SG network, and the protocols used for this task must be able to protect against possible attacks (for example, Man- in-the-Middle - MITM, repetição, Denegação de Serviço – DoS). On the other hand, authorization is treated jointly with authentication and related to policies of access control to the system. An essential part of creating secure authentication protocols involves encryption schemes. The use of one or the combination of several schemes directly affects protocol performance. Each day new schemas are proposed, and their utilization in the authentication protocols improves the performance of the system compared to the protocols already proposed in the same scenario. In this work 3 (three) secure and cost-effective authentication protocols are proposed, for the following scenarios: - Authentication of employees of energy suply enterprises, looking for remote or local access to the system; - Authentication of Smart Meters in an Advanced Metering Infrastructure based on cloud computing; and - Authentication of electrical vehicles in a V2G (“Vehicle-to-Grid”) network. Each scenario has specific characteristics, that are reflected on the design of the proposed protocols. Moreover, such protocols assure mutual authentication among entities as well as the protection of privacy, confidentiality and integrity of system data. A comparison considering communication and computing costs is presented, involving proposed protocols and other previously published protocols, for each scenario. The results show that the proposed protocols have, in most cases, the best performance, thus constituting good choices for future implementation in SG networks. The formal validation of the proposed protocols by the use of AVISPA tool is realized, allowing to verify the compliance with security requirements

Contactless payments :usability at the cost of security?

PhD ThesisEMV (Europay, MasterCard, Visa), commonly termed “Chip & PIN”, is becoming the dominant card based payment technology globally. The EMV Chip & PIN transaction protocol was originally designed to operate in an environment where the card was physically inserted into the POS terminal / ATM and used a wired connection to communicate. The introduction of EMV contactless payments technology raises an interesting question “has usability been improved at the cost of security?”. Specifically, to make contactless payments more convenient / usable, a wireless interface has been added to EMV cards and PIN entry has been waived for contactless payments. Do these new usability features make contactless cards less secure? This PhD thesis presents an analysis of the security of the EMV contactless payments. It considers the security of the EMV contactless transaction protocols as stand-alone processes and the wider impact of contactless technology upon the security of the EMV card payment system as a whole. The thesis contributes a structured analysis methodology which identifies vulnerabilities in the EMV protocol and demonstrates the impact of these vulnerabilities on the EMV payment system. The analysis methodology comprises UML diagrams and reference tables which describe the EMV protocol sequences, a protocol emulator which implements the protocol, a Z abstract model of the protocol and practical demonstrations of the research results. Detailed referencing of the EMV specifications provide a documented link between the exploitable vulnerabilities observed in real EMV cards and the source of the vulnerability in the EMV specifications. Our analysis methodology has identified two previously undocumented vulnerabilities in the EMV contactless transaction protocol. The potential existence of these vulnerabilities was identified using the Z abstract model with the protocol emulator providing experimental confirmation of the potential for real-world exploitation of the vulnerabilities and test results quantifying the extent of the impact. Once a vulnerability has been shown to be exploitable using the protocol emulator, we use practical demonstrations to show that these vulnerabilities can be exploited in the real-world using off-the-shelf equipment. This presents a stronger impact message when presenting our research results to a nontechnical audience. This has helped to raise awareness of security issues relating to EMV contactless cards, with our work appearing in the media, radio and TV