Electronic Commerce Research and Applications, vol. 3, no. 2, Elsevier, pp. 152-162, 2004.
Non-repudiation is a security service that provides cryptographic evidence to support the settlement of disputes in electronic commerce. In commercial transactions, an intermediary (or agent) might be involved to help transacting parties to conduct their business. Nevertheless, such an intermediary may not be fully trusted. In this paper, we propose agent-mediated non-repudiation protocols and analyze their security requirements. We first present a simple scenario with only one recipient, followed by a more complicated framework where multiple recipients are involved and collusion between them is possible. We also identify applications that could take advantage of these agent-mediated non-repudiation protocols.
Computer Communications, vol. 29, no. 15, Elsevier, pp. 2739-2749, 2006. DOI (I.F.: 0.444)
Unsolicited Commercial Email, or Spam, is nowadays an increasingly serious problem to email users. A number of anti-spam schemes have been proposed in the literature and some of them have been deployed in email systems, but the problem has yet been well addressed. One of those schemes is challenge-response, in which a challenge, ranging from a simple mathematical problem to a hard-AI problem, is imposed on an email sender in order to forbid machine-based spam reaching receivers’ mailboxes. However, such a scheme introduces new problems for the users, e.g., delay of service and denial of service. In this paper, we introduce the pre-challenge scheme, which is based on the challenge-response mechanism and takes advantage of some features of email systems. It assumes each user has a challenge that is defined by the user himself/herself and associated with his/her email address, in such a way that an email sender can simultaneously retrieve a new receiver’s email address and challenge before sending an email in the first contact. Some new mechanisms are employed in our scheme to reach a good balance between security against spam and convenience to normal email users. Our scheme can be also used for protecting other messaging systems, like Instant Messaging and Blog comments.
Sensors, vol. 10, pp. 3718-3731, 2010.
International Journal of Computer Systems Science & Engineering, vol. 3, CRL Publishing, pp. 185-192, 2005. (I.F.: 0.119)
Virtual Private Networks (VPNs) provide a cost-effective way for securing communications using public and insecure networks like the Internet. The main purpose of a VPN is to securely and transparently connect two or more remote networks to form virtually a single network, using centralized security policies for better management and protection. However, in certain scenarios, users may not require such a transparent access to the resources within their networks, but only want temporary secure access to internal services based on their own demands. We call the network architecture with such a feature as Casual VPN. In this paper, we present the notion of Casual VPN, and explain why traditional VPN architectures and protocols are unable to offer Casual VPN services. We also propose and define the operation of a particular Casual VPN architecture, C-VPN, which additionally allows the management of TCP and UDP-based protocols.
IEEE Computer, vol. 46, no. 10, IEEE Computer Society, pp. 74 - 83, 2013. DOI (I.F.: 1.438)
Information systems, networks, and technologies have become an integral part of modern critical control systems that manage many of today&#x2019;s critical infrastructures. The continuous operation, maintenance, and protection of critical infrastructures have become a high national priority for governments around the world because our society heavily depends on them for most of our daily activities (travel, power usage, banking transactions, telecommunications, etc) and safety. It is therefore critical that these infrastructures have to be protected from potential accidental incidents or cyberattacks. We present the fundamental architectural components of critical control systems which manage most critical infrastructures. We identify some of the vulnerabilities and threats to modern critical control systems followed by protection solutions that can be deployed to mitigate attacks exploiting these vulnerabilities.
International Journal of Critical Infrastructure Protection (IJCIP), vol. 8, Elsevier Science, pp. 53–66, 01/2015. DOI (I.F.: 1.351)
Critical infrastructures play a vital role in supporting modern society. The reliability, performance, continuous operation, safety, maintenance and protection of critical infrastructures are national priorities for countries around the world. This paper explores the vulnerabilities and threats facing modern critical infrastructures with special emphasis on industrial control systems, and describes a number of protection measures. The paper also discusses some of the challenging areas related to critical infrastructure protection such as governance and security management, secure network architectures, self-healing, modeling and simulation, wide-area situational awareness, forensics and learning, and trust management and privacy.
Information Security Technical Report, vol. 12, no. 3, Elsevier, pp. 179-185, 2007. DOI
Spam is a big problem for email users. The battle between spamming and anti-spamming technologies has been going on for many years. Though many advanced anti-spamming technologies are progressing significantly, spam is still able to bombard many email users. The problem worsens when some anti-spamming methods unintentionally filtered legitimate emails instead! In this paper, we first review existing anti-spam technologies, then propose a layered defense framework using a combination of anti-spamming methods. Under this framework, the server-level defense is targeted for common spam while the client-level defense further filters specific spam for individual users. This layered structure improves on filtering accuracy and yet reduces the number of false positives. A sub-system using our pre-challenge method is implemented as an add-on in Microsoft Outlook 2002. In addition, we extend our client-based pre-challenge method to a domain-based solution thus further reducing the individual email users’ overheads.
Computer Networks, vol. 57, Elsevier, pp. 2266–2279, July 2013. DOI (I.F.: 1.282)
In the Internet of Things, services can be provisioned using centralized architectures, where central entities acquire, process, and provide information. Alternatively, distributed architectures, where entities at the edge of the network exchange information and collaborate with each other in a dynamic way, can also be used. In order to understand the applicability and viability of this distributed approach, it is necessary to know its advantages and disadvantages – not only in terms of features but also in terms of security and privacy challenges. The purpose of this paper is to show that the distributed approach has various challenges that need to be solved, but also various interesting properties and strengths.
Telecommunications Systems, vol. 35, pp. 161-176, September, 2007.
In any kind of electronic transaction, it is extremely important to assure that any of the parties involved can not deny their participation in the information exchange. This security property, which is called non-repudiation, becomes more important in Digital Rights Management (DRM) scenarios, where a consumer can freely access to certain contents but needs to obtain the proper Right Object (RO) from a vendor in order to process it. Any breach in this process could result on financial loss for any peer, thus it is necessary to provide a service that allows the creation of trusted evidence. Unfortunately, non-repudiation services has not been included so far in DRM specifications due to practical issues and the type of content distributed. In this paper we analyze how to allow the integration of non-repudiation services to a DRM framework, providing a set of protocols that allows the right objects acquisition to be undeniable, alongside with a proof-of-concept implementation and a validation process.
ACM Comput. Surveys, vol. 41, no. 1, pp. 5, December, 2008. (I.F.: 9.92)
Nonrepudiation is a security service that plays an important role in many Internet applications. Traditional two-party nonrepudiation has been studied intensively in the literature. This survey focuses on multiparty scenarios and provides a comprehensive overview. It starts with a brief introduction of fundamental issues on nonrepudiation, including the types of nonrepudiation service and cryptographic evidence, the roles of trusted third-party, nonrepudiation phases and requirements, and the status of standardization. Then it describes the general multiparty nonrepudiation problem, and analyzes state-of-the-art mechanisms. After this, it presents in more detail the 1-N multiparty nonrepudiation solutions for distribution of different messages to multiple recipients. Finally, it discusses advanced solutions for two typical multiparty nonrepudiation applications, namely, multiparty certified email and multiparty contract signing.
Computer Communications, vol. 27, no. 16, pp. 1608-1616, 2004. (I.F.: 0.574)
Non-repudiation is a security service that provides cryptographic evidence to support the settlement of disputes. In this paper, we introduce the state-of-the-art of non-repudiation protocols for multiple entities. We extend an existing multi-party non-repudiation (MPNR) protocol to allow an originator to send different messages to many recipients in a single transaction. We further propose an optimistic multi-party non-repudiation protocol for exchange of different messages. The performance of our protocols with enhanced functionalities is still promising in comparison with existing MPNR protocols.
Information Management & Computer Security Journal, vol. 13, no. 5, pp. 350-366, 2005.
As a value-added service to deliver important data over the Internet with guaranteed receipt for each successful delivery, certified email has been discussed for years and a number of research papers appeared in the literature. But most of them deal with the two-party scenarios, i.e., there are only one sender and one recipient. In some applications, however, the same certified message may need to be sent to a set of recipients. In this paper, we presents two optimized multi-party certified email protocols. They have three major features. (1) A sender could notify multiple recipients of the same information while only those recipients who acknowledged are able to get the information. (2) Both the sender and the recipients can end a protocol run at any time without breach of fairness. (3) The exchange protocols are optimized, each of which have only three steps.
Concurrency and Computation Practice & Experience, vol. 23, no. 12, John Wiley & Sons, Inc., pp. 1414-1430, Aug 2011. DOI (I.F.: 0.636)
Energy distribution systems are becoming increasingly widespread in today’s society. One of the elements that is used to monitor and control these systems are the SCADA (Supervisory Control and Data Acquisition) systems. In particular, these control systems and their complexities, together with the emerging use of the Internet and wireless technologies, bring new challenges that must be carefully considered. Examples of such challenges are the particular bene¯ts of the integration of those new technologies, and also the e®ects they may have on the overall SCADA security. The main task of this paper is to provide a framework that shows how the integration of di®erent state-of-the-art technologies in an energy control system, such as Wireless Sensor Networks (WSNs), Mobile Ad-Hoc Networks (MANETs), and the Internet, can bring some interesting benefits such as status management and anomaly prevention, while maintaining the security of the whole system.
Wireless Personal Communications, vol. 73, Springer, pp. 23-50, Nov 2013, 2012. DOI (I.F.: 0.428)
The smart grid is an electronically controlled electrical grid that connects power generation, transmission, distribution, and consumers using information communication technologies. One of the key characteristics of the smart grid is its support for bi-directional information flow between the consumer of electricity and the utility provider. This two-way interaction allows electricity to be generated in real-time based on consumers’ demands and power requests. As a result, consumer privacy becomes an important concern when collecting energy usage data with the deployment and adoption of smart grid technologies. To protect such sensitive information it is imperative that privacy protection mechanisms be used to protect the privacy of smart grid users. We present an analysis of recently proposed smart grid privacy solutions and identify their strengths and weaknesses in terms of their implementation complexity, efficiency, robustness, and simplicity.
Journal of Computer Security, vol. 27, issue 5, Elsevier, pp. 521-546, 09/2019. (I.F.: 3.579)