Jorge L. Hernandez-Ardieta

Publications (22) View all

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  Available from: Jorge L. Hernandez-Ardieta

  Thesis: Enhancing the reliability of digital signatures as non-repudiation evidence under a holistic threat model

  Jorge Lopez Hernandez-Ardieta
  01/2011, Degree: Ph.D. in Computer Science, Supervisor: Prof. Dr. Ana Isabel Gonzalez-Tablas Ferreres
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  Available from: Jorge L. Hernandez-Ardieta

  Conference Proceeding: Harmonizing Common Criteria and Formal Risk Analysis Methodologies: Security Target Construction through Risk Analysis

  Jorge Lopez Hernandez-Ardieta, David Vara Cuesta
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  ABSTRACT: Common Criteria (CC) establishes a methodology to evaluate the security claimed by information technology products. As a requisite of CC-based evaluations, the manufacturer has to provide a formal document named security target, in which a security problem definition must be included along with the security objectives met by the product and the implemented security functional requirements (SFRs). The security problem definition contains the assets to protect, the expected threats to those assets, the existent organizational security policies and the assumptions made, being most of this information typically obtained from a formal risk analysis (RA). A RA is a process that organizations shall carry out to determine appropriate and cost-effective security controls to protect their ICT systems. By means of a RA, the level of security risk on the organization’s assets can be calculated. The risk level usually depends on the probability of occurrence of the considered threats and the potential impact should these threats occur. In a RA, the reduction of the risk level can also be estimated, being able to decide the appropriate security controls to implement in order to achieve an acceptable residual risk level. It is thus clear that the output of a RA process can help to approximate a CC evaluation, and, in particular, to shape the security target content. However, CC and RA methodologies follow opposite approaches. In the former, the evaluation result is binary. Either the ICT product resists the vulnerability analysis performed by the evaluators, or it does not. In the latter, the organization pursues a residual level of risk, which is never zero (due to the costs). This means that SFRs intend to completely counteract the attacks which the product is exposed to, while the security controls intend to mitigate (not eliminate) the risk by reducing the impact of the threats, their probability of occurrence, or both. In this presentation we will explain a methodology developed to combine formal RA and CC in a harmonized way, permitting to automatically derive the SFRs from the security controls selected in the RA, and to decide the evaluation assurance level (EAL) to achieve depending on the potential risk estimated in the RA. Our methodology fills the current gap between RA and CC, offering a time-save and accurate approach to write security targets. Furthermore, it is possible to specify a different EAL for different sets of SFRs, in a manner that composite evaluation could benefit from it. We will also present the results of using our methodology in a complex ICT system, proving its applicability in a concrete and demanding scenario.
  12th International Common Criteria Conference, Selangor, Malaysia; 01/2011
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  Available from: Jorge L. Hernandez-Ardieta

  Conference Proceeding: Aumento de la Fiabilidad de la Evidencia en un Protocolo de Intercambio Justo mediante la División del Entorno de Firma

  Jorge L. Hernandez-Ardieta, Ana I. Gonzalez-Tablas, Benjamin Ramos Alvarez, Arturo Ribagorda Garnacho
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  ABSTRACT: El respaldo legal de la firma electrónica unido a su reconocimiento como evidencia de no repudio por parte de los estándares internacionales hace que la seguridad del proceso de creación de firmas sea una cuestión de suma importancia. Sin embargo, numerosos estudios demuestran que existe una gran variedad de ataques a entornos de creación de firmas, lo cual socava la fiabilidad de la firma electrónica como evidencia de no repudio y evidencia en procedimientos legales. En este artículo se presenta un protocolo en el cual se aumenta considerablemente la fiabilidad de la evidencia generada aun cuando el firmante emplea un entorno de creación de firmas inseguro. El protocolo se ha diseñado tomando como base un protocolo de intercambio justo presentado con anterioridad, en el cual se asegura que ningún participante obtiene una ventaja respecto al otro durante la transacción.
  Congreso Iberoamericano de Seguridad Informática (CIBSI'09), Montevideo, Uruguay; 11/2009
• Conference Proceeding: Extended Electronic Signature Policies

  Jorge L. Hernandez-Ardieta, Ana I. Gonzalez-Tablas, Benjamin Ramos, Arturo Ribagorda
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  ABSTRACT: A signature policy collects the rules to create and validate electronic signatures under which they become binding in a particular transactional context. These policies have been widely adopted to enforce the binding property of signatures in business scenarios. However, current standards only cover the definition of the requirements to be fulfilled by a single signature. As a consequence, business models where more than one signature is required in order to make the transaction effective cannot adhere to the benefits of signature policies. This paper is the first to propose a solution where the dependences and relationships among the signatures generated in the same transaction can be established. In particular, the ASN.1 definition of an extended signature policy is presented along with the procedures to be followed by the transacting parties. This work will be submitted to the IETF PKIX Work Group to be considered as an Experimental Request For Comments document (RFC).
  ACM 2nd International Conference on Security of Information and Networks (SIN 2009), Cyprus; 10/2009
• Chapter: Formal Validation of OFEPSP+ with AVISPA

  Jorge L. Hernandez-Ardieta, Ana I. Gonzalez-Tablas, Benjamin Ramos
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  ABSTRACT: Formal validation of security protocols is of utmost importance before they gain market or academic acceptance. In particular, the results obtained from the formal validation of the improved Optimistic Fair Exchange Protocol based on Signature Policies (OFEPSP+) are presented. OFEPSP+ ensures that no party gains an unfair advantage over the other during the protocol execution, while substantially reducing the probability of a successful attack on the protocol due to a compromise of the signature creation environment. We have used the Automated Validation of Internet Security Protocols and Applications (AVISPA) and the Security Protocol ANimator for AVISPA (SPAN), two powerful automated reasoning technique tools to formally specify and validate security protocols for the Internet.
  08/2009: pages 124-137;