Fair exchange is an important tool to achieve "fairness" of electronic commerce. Several previous schemes satisfy universally composable security which provides security preserving property under complex net...
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Fair exchange is an important tool to achieve "fairness" of electronic commerce. Several previous schemes satisfy universally composable security which provides security preserving property under complex networks like the Internet. In recent years, as the demand for electronic commerce increases, fair exchange for electronic vouchers (e.g., electronic tickets, moneys, etc.) to obtain services or contents is in the spotlight. The definition of fairness for electronic vouchers is different from that for general electronic items (e.g., the sender must not do duplicate use of exchanged electronic vouchers). However, although there are universally composable schemes for electronic items, there is no previous study for electronic vouchers. In this paper, we introduce a universally composable definition of fair voucher exchange, that is, an ideal functionality of fair voucher exchange. Also, we prove the equivalence between our universally composable definition and the conventional definition for electronic vouchers. Thus, our formulation of the ideal functionality is justified. Finally, we propose a new fair voucher exchange scheme from non-blocking atomic commitment, as black-box, which satisfies our security definition and is adequate for mobile environments. By instantiating general building blocks with known practical ones, our scheme can be also practical because it is implemented without trusted third party in usual executions.
The secure execution of a mobile agent is a very important design issue in building a mobile agent system and many fault-tolerant schemes have been proposed so far. Mobile agents are no longer a theoretical issue sinc...
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ISBN:
(纸本)0780391799
The secure execution of a mobile agent is a very important design issue in building a mobile agent system and many fault-tolerant schemes have been proposed so far. Mobile agents are no longer a theoretical issue since different architectures for their realization have been proposed In the context of e-commerce, execution atomicity is an important property for mobile agents. A mobile agent executes atomically, if either all its operations succeed, or none at all. This requires to solve an instance of the atomiccommitment problem. However, it is important that failures (e.g., of machines or agents) do not lead to blocking of transactional mobile agents, i.e., agents that execute as a transaction. In this paper, we give a novel specification of non-blocking atomic commitment in the context of mobile agent execution. Fault tolerance for mobile agent systems is an unsolved topic, to which more importance should be attached. Besides the security problems by intended attacks it is very important to realize that an agent can simply get lost by errors of the network or the hosts. We then show how transactional mobile agent execution can be built on top of earlier work on fault-tolerant mobile agent execution and give preliminary performance results.
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