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Recently we have observed the growth of the intelligent application especially with its mobile character, called e-anything. The implementation of these applications provides guarantee of security requirements of the cryptographic protocols which are used in the application. Traditionally the protocols have been configured with the strongest possible security mechanisms. Unfortunately, when the application is used by means of the mobile devices, the strongest protection can lead to the denial of services for them. The solution of this problem is introducing the quality of protection models which will scale the protection level depending on the actual threat level. In this article we would like to introduce the application which manages the protection level of the processes in the mobile environment. The Security Protocol Optimizing Tool (SPOT) optimizes the cryptographic protocol and defines the protocol version appropriate to the actual threat level. In this article the architecture of the SPOT is presented with a detailed description of the included modules. [ABSTRACT FROM AUTHOR]

We provide the first description of and security model for authenticated key exchange protocols with predicate-based authentication. In addition to the standard goal of session key security, our security model also provides for credential privacy: a participating party learns nothing more about the other party΄s credentials than whether they satisfy the given predicate. Our model also encompasses attribute-based key exchange since it is a special case of predicate-based key exchange. We demonstrate how to realize a secure predicate-based key exchange protocol by combining any secure predicate-based signature scheme with the basic Diffie-Hellman key exchange protocol, providing an efficient and simple solution. [ABSTRACT FROM AUTHOR]

This paper presents a theory of runtime enforcement based on mechanism models called MRAs (Mandatory Results Automata). MRAs can monitor and transform security-relevant actions and their results. Because previous work could not model monitors transforming results, MRAs capture realistic behaviors outside the scope of previous models. MRAs also have a simple but realistic operational semantics that makes it straightforward to define concrete MRAs. Moreover, the definitions of policies and enforcement with MRAs are significantly simpler and more expressive than those of previous models. Putting all these features together, we argue that MRAs make good general models of runtime mechanisms, upon which a theory of runtime enforcement can be based. We develop some enforceability theory by characterizing the policies MRAs can and cannot enforce. [ABSTRACT FROM AUTHOR]

The aim of this paper is to address the problems associated with the current wireless ad-hoc networks, which are characterized by the lack of infrastructure. This characteristic makes it difficult to apply generic administrative approaches to solve problems such as intrusion detection. Due to the dynamic changes of topology in such networks, it is difficult to determine whether the node participating in the routing domain is Byzantine or indeed an authenticated node. The paper discusses also how mobile agent technology can be used to perform the authentication mechanism, and hence improve the utilization of the network bandwidth and provide an efficient profile management in mobile ad-hoc networks. [ABSTRACT FROM AUTHOR]

Certificate-based encryption was introduced in Eurocrypt΄03 to solve the certificate management problem in public key encryption. Recently, this idea has been extended to certificate-based signatures. To date, several new schemes and security models of certificate-based signatures have been proposed. In this paper, we first introduce a new security model of certificate-based signatures. Our model is not only more elaborated when compared with the existing ones, but also defines several new types of adversaries in certificate-based signatures. We then investigate the relationship between certificate-based signatures and certificateless signatures, by proposing a generic construction of certificate-based signatures from certificateless signatures. Our generic construction is secure (in the random oracle model) under the security model defined in this paper, assuming the underlying certificateless signatures satisfying certain security notions. [ABSTRACT FROM AUTHOR]

The notion of certified encryption had recently been suggested as a suitable setting for analyzing the security of encryption against adversaries that tamper with the key-registration process. The flexible syntax afforded by certified encryption suggests that identity-based and certificateless encryption schemes can be analyzed using the models for certified encryption. In this paper we explore the relationships between security models for these two primitives and that for certified encryption. We obtain the following results. We show that an identity-based encryption scheme is secure if and only if it is secure when viewed as a certified encryption scheme. This result holds under the (unavoidable) restriction that registration occurs over private channels. In the case of certificateless encryption we observe that a similar result cannot hold. The reason is that existent models explicitly account for attacks against the non-monolithic structure of the secret keys whereas certified encryption models treat secret keys as whole entities. We propose an extension for certified encryption where the adversary is allowed to partially modify the secret keys of honest parties. The extension that we propose is very general and may lead to unsatisfiable notions. Nevertheless, we exhibit one instantiation for which we can prove the desired result: a certificateless encryption is secure if and only if its associated certified encryption scheme is secure. As part of our analysis, and a result of separate interest we confirm the folklore belief that for both IBE and CLE, security in the single-user setting (as captured by existent models) is equivalent to security in the multi-user setting. [ABSTRACT FROM AUTHOR]

In this paper, we focus on security models in steganography. We first recall classical security models both in cryptography and in steganography. We rely on these models to propose the definitions of the malleability-based models of security for private key steganographic schemes. We also prove that the indistinguishability-based security under the hypothesis of a chosen hidden text adaptive attack (IND-CHA2) implies malleability-based security under the same hypothesis (NM-CHA2). This connection gives us some keys to explain why many practical steganography schemes do not resist adaptive adversaries. Finally, we propose a generic construction to overcome the intrinsic vulnerability of many of them induced by the malleability property. [ABSTRACT FROM AUTHOR]

This paper describes three practical techniques for authenticating the code and other execution state of an operating system using the services of the TPM and a hypervisor. The techniques trade off detailed reporting of the OS code and configuration with the manageability and comprehensibility of reported configurations. Such trade-offs are essential because of the complexity and diversity of modern general purpose operating systems makes simple code authentication schemes using code hashes or certificates infeasible. [ABSTRACT FROM AUTHOR]

In this paper, we propose to link practical steganalysis and classical security models. In one hand, some steganography schemes are proved to be secure in some security models but in practice, they cannot be used in real-life because of too many constrains. In the other hand, lots of practical steganography algorithms have been broken by effective steganalysis but without any connection with standard models of attackers. So, we introduce two new types of adversaries to simulate real attackers, the IND-SSA adversary and the IND-USA adversary. The IND-SSA adversary emulates specific steganalysis whereas the IND-USA attacker stands for universal steganalysis. We also define the games and the security models associated with and formalize discrimination attacks and discriminant steganalysis. Then, we connect these new models with the hierarchy of classical security models. Using models introduced by C. Cachin, S. Katzenbeisser and F. Petitcolas, and finally by N. Hopper, we show how effective steganalysis gives us a lower bound on the insecurity of the steganalyzed steganography schemes. We also point out that steganography schemes which are not secure in these new models are also not secure in the classical models of security. [ABSTRACT FROM AUTHOR]