In addition to maintaining consistency of the database, secure concurrency control algorithms must be free from covert channels arising due to data conflicts between transactions. The existing secure concurrency control approaches are unfair to transactions at higher access classes. In this paper, a secure two-phase locking protocol is presented, which is correct and free from covert channels. ...

We design and analyze a simple optimistic fair non-repudiation protocol. Our protocol isconsiderably simpler and more efficient than current proposals, due mainly to the avoidanceof using session labels. We model-check both safety and liveness properties. We verify thesafety properties using a standard intruder, and the liveness properties using an intruderthat respects the resi...

In the present study, we investigate impact of discounts on valuation performance initial public offerings. Review existing literature reveals that such lacks examination in terms as most studies focus methods. Accordingly, examine offerings before and after applying discounts. Whereby, underwriters apply a deliberate discount to fair value estimate setting final offer price. We assess through ...

The ASW protocol is one of the prominent optimistic fair exchange protocols that is used for contract signing between two participants, the originator and the responder, with the aid of a trusted third party in case of a dispute. In this paper, the key security objectives of ASW protocol — fairness, effectiveness and timeliness — have been verified using a probabilistic model checking tool, PRI...

Non-repudiation Protocols. During the last decade open networks, above all the Internet, have known an impressive growth. As a consequence, new security issues, like non-repudiation have to be considered. Repudiation is de ned as the denial of an entity of having participated in all or part of a communication. Consider for instance the following scenario: Alice wants to send a message to Bob; a...

An untraceable fair network payment protocol is proposed by Wang in Asiacrypt’03, which employs the existent techniques of the offline untraceable cash and a new technique called restrictive confirmation signature scheme (RCSS). It is claimed that the fair payment protocol has both the fairness such that the buyer obtains the digital goods if and only if the merchant gains the digital cash and ...

This paper studies the fairness with which competing flows share the channel in ad hoc networks using collision avoidance protocols. It is shown that the required multihop coordination makes the backoff-based distributed fair queueing schemes less effective. Using extensive simulations of two competing flows with different underlying network configurations, it is shown that the commonly used fl...