Universally Composable NBAC-Based Fair Voucher Exchange for Mobile Environments

Masayuki TERADA
Sadayuki HONGO
Kazuo OHTA

IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences   Vol.E94-A    No.6    pp.1263-1273
Publication Date: 2011/06/01
Online ISSN: 1745-1337
DOI: 10.1587/transfun.E94.A.1263
Print ISSN: 0916-8508
Type of Manuscript: Special Section PAPER (Special Section on Discrete Mathematics and Its Applications)
fairness,  fair exchange,  electronic voucher,  universal composability,  non-blocking atomic commitment,  

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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.