Catálogo de publicaciones - libros

The first generation of European e-passports will be issued in 2006. We discuss how borders are crossed regarding the security and privacy erosion of the proposed schemes, and show which borders need to be crossed to improve the security and the privacy protection of the next generation of e-passports. In particular we discuss attacks on Basic Access Control due to the low entropy of the data from which the access keys are derived, we sketch the European proposals for Extended Access Control and the weaknesses in that scheme, and show how fundamentally different design decisions can make e-passports more secure.

Automated trust negotiation (ATN) is an important approach to establish trust between strangers through the exchange of credentials and access control policies. In practice, access control policy may contain sensitive information. The negotiation process becomes complicated when the access control policy is designed complex in order to avoid information leakage. Furthermore, if the access control policy has conflicts or cycles, normal negotiation strategies often fail. In this paper, a new approach to hide access control policy is proposed based on the study on the existing problems. In the approach, the policy consistency is checked so as to detect policy conflicts. 0-1 table is used to implement it as well as discover minimal credential-set. Meanwhile, a practical example shows that the approach is suitable and can effectively protect sensitive information in access control policy.

We present an approach to protect mobile code and agents at runtime using Trusted Computing (TC) technologies. For this purpose, a “mobile policy” is defined by the mobile code originator, and is enforced by the runtime environment in a remote host to control which users can run the mobile code and what kind of results a user can observe, depending on the security properties of the user. The separation of policy specification and implementation mechanism in existing mobile computing platform such as Java Runtime Environment (JRE) enables the implementation of our approach by leveraging current security technologies. The main difference between our approach and existing runtime security models is that the policies enforced in our model are intended to protect the resources of the mobile applications instead of the local system resources. This requires the remote runtime environment to be trusted by the application originator to authenticate the remote user and enforce the policy. Emerging TC technologies such as specified by the Trusted Computing Group (TCG) provide assurance of the runtime environment of a remote host.

is a process by which one IP node acts as an endpoint intermediary for an IP address that actually belongs to another IP node. Address proxying serves many useful functions in IP networks. In IPv6, the Secure Neighbor Discovery Protocol (SEND) provides powerful tools for securing the mapping between the IP address and the link address which is the basis of local link address proxying; however, these tools don’t work for address proxies. In this paper, we present an extension to SEND for secure proxying. As an example of how secure address proxying can be used, we propose a minor extension of the Mobile IPv6 protocol to allow secure proxying by the home agent. We then present measurements comparing SEND with and without the address proxying extensions.

The digital watermark is used for detection of digital image alteration. However, most of digital images are printed on the paper document for submitting. Once digital images are printed on the paper, it is hard to detect alteration of it. In this paper, the detection method of printed image alteration by using digital watermark is proposed.

This paper addresses implementation issues for real-time watermark embedding scheme of High Definition(HD) resolution videos on personal computers. In most watermark applications, an embedding procedure should be built at low costs and at the same time the embedded watermarks should have robustness against signal and image processing as well as malicious attacks. This paper provides some performance optimization guidelines and a simplified Human Visual System (HVS) method for fast and robust watermark embedding. This work demonstrates a real-time watermark embedding process including HD MPEG-2 video decoding, watermark embedding and displaying on Intel architecture personal computers. Experimental results show optimized embedding performances and robustness against several malicious attacks commonly happened to videos.

The satellite TV industry relies heavily on the use of smart card technology at the very heart of broadcasted services that are protected by legacy conditional access systems. The process of Satellite TV signal protection is distributed amongst a number of system components, e.g. smart cards, receivers, Conditional Access Modules (CAM) and the content provider. However, the introduction of “Open” Satellite Receivers, providing a highly configurable environment with software emulation of conditional access systems, enabled the implementation of whole range of new attacks. A widely deployed attack is often referred to as the “card sharing” attack, by which one legitimate user colludes to provide protected content to a larger group of unauthorised users. This paper proposes a countermeasure that increases the bandwidth requirements of this attack to the point where it is no longer practical with a standard internet connection, with a minimal impact on existing protocols and architectures.

This paper analyzed the features of the flooding-based DoS/DDoS attack traffic, and proposed a novel real-time algorithm for detecting such DoS/DDoS attacks. In order to shorten the delay of detection, short-term traffic prediction was introduced, and prediction values were used in the detecting process. Though we use real-time traffic data to calculate the mean and variance, few periods of data need to be stored because the algorithm is a recurring process, therefore the occupied storage space is less. Moreover, the complex and cost of the recurring process is less than calculating the whole sequence, so the load of the server would not increase much. Although we focus our research on detecting flooding-based DoS/DDoS attacks, the simulation shows that the approach also can deal with DDoS attacks that zombies start without simultaneousness.

Currently, a buffer overflow attack is one of the most serious and widely utilized assaults in computer systems. Defense methods against this attack can be classified as three: compiler modification, system software modification, and hardware modification. Among them, most of the cases, hardware modification methods aim at detecting or tolerating alternation of return addresses in the memory stack. However, to the best of our knowledge, the previous methods cannot defend against frame pointer overwrite attacks, where an adversary can control the execution at his/her will by modifying the saved frame pointers in the stack. In this paper, we present a new reliable hardware stack to detect alternation of saved frame pointers as well as return addresses. We show that the proposed method can defend against both frame pointer overwrite attacks and stack smashing attacks.

In the TCP network environment, all unit transmissions are constructed using sessions. In the session, packets are transmitted sequentially. In this case, the previous and next packets contain causality mutually. Thus, we propose a method that models network transmission information based on transitions of packet states. In addition to the transition model, a probability matrix for the multiple state-transition models of all sessions is represented. The matching of the models is achieved using the maximum log-likelihood ratio. Evaluation of the proposed method for intrusion modeling is conducted by using 1999 DARPA data sets. The method is also compared with Snort-2 which is misuse-based intrusion detection system. In addition, the techniques for advancing proposed method are discussed.