Mobile ad hoc network (MANET) is an infrastructureless mobile networks where nodes can freely move and join. MANET has attracted much attention in recent years owing to the increased focus on wireless communication. It is a highly flexible network, vulnerable to various types of security attacks by malicious nodes. Ensuring network security is a major concern in the case of MANET. Certificate r...

This Technical Report is the second of a sequence of five reports that analyse the problem of the interoperability between the EDI and X.509 worlds, and specify one possible solution in order to eliminate the barriers of communication between both certification infrastructures. This sequence of works have been structured in two parts. The first part is concentrated in the incompatibility betwee...

Featured with anonymity and spontaneity, ring signature has been widely adopted in various environments to offer anonymous authentication. To simplify the certificate management in traditional public key infrastructure (PKI) and solve the inherent key escrow problem in the Identity-based cryptography, Qin et al. propose a pairingfree ring signature scheme in the certificate-based cryptosystem r...

Most of the security architecture uses public key cryptosystems for authentication and to secure the communication that takes place on distributes sites. Now a day’s identity based cryptography and certificate-less public key cryptography are used for enhancing the security. Certificate-less based cryptography has reduced the certificate necessity for key distribution and reducing the problem o...

A wide spectrum of certificate revocation mechanisms is currently in use. A number of them have been proposed by standardisation bodies, while some others have originated from academic or private institutions. What is still missing is a systematic and robust framework for the sound evaluation of these mechanisms. We present a mechanism-neutral framework for the evaluation of certificate status ...

This article describes three experiments designed to investigate the effects of competition and attachment on auction bidder behavior. For each study, in order to isolate bidders' desire to win the item from bidders’ desire to simply win the auction, we constructed survey experiments with participants divided into two groups. Both groups bid on a certificate that could be exchanged for an attra...

An isomorphism certificate of a labeled tournament T is a labeled subdigraph of T which together with an unlabeled copy of T allows the errorless reconstruction of T . It is shown that any tournament on n vertices contains an isomorphism certificate with at most n log2 n edges. This answers a question of Fishburn, Kim and Tetali. A score certificate of T is a labeled subdigraph of T which toget...

The authors present an automatic method for the synthesis of certificates for components in embedded real-time systems. A certificate is a small homomorphic abstraction that can transparently replace the component during model checking: if the verification with the certificate succeeds, then the component is guaranteed to be correct; if the verification with the certificate fails, then the comp...

In ad-hoc networks and other highly distributed and decentralized environments, authorization certificates can be used to control access. Moreover, it is possible to delegate rights listed in the certificate to another users. Several such subsequent delegations build a chain of certificates. Chains of delegation certificates can improve the capability and manageability of systems. Distributed g...

Security poses a major challenge in ad hoc networks today due to the lack of fixed or organizational infrastructure. This paper proposes a modification to the existing “fully distributed certificate authority” scheme for ad hoc networks. In the proposed modification, redundancy is introduced by allocating more than one share to each node in order to increase the probability of creating the cert...