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| Format: | Artículo científico |
| Language: | en |
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Universidad de Talca
2006
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| Online Access: | https://www.redalyc.org/articulo.oa?id=96510102 |
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Table of Contents:
- Digital Coins: Fairness Implemented by Observer Heike Neumann Thomas Schwarzpaul Multidisciplinaria (Ciencias Naturales y Exactas) observer fairness digital coins Electronic cash For real-world applications digital coin systems, i.e., off-line payment systems offering not only the unforgeability ofconventional coins but also the anonymity of customers making purchases, need to have some additional features.One of these additional features is the hardware protection of the system, provided by dedicated tamper-resistantdevices called observers which are used to physically prevent illegitimate copying of coins.Another essential feature for practical applications is anonymity-revocation mechanisms. Basically, digital coinsystems guarantee perfect anonymity, i.e., the bank cannot link views of the withdrawal and payments in order todetermine whether or not a customer spent her money at a certain shop. The customer´s privacy protection is the maindifference between coin systems and those based on credit card or cheque based systems. While privacy protection isa desirable property of cash systems, perfect anonymity is not. Perfect anonymity makes possible perfect blackmailingor money laundering. To prevent such perfect crime it must be possible to revoke the anonymity of customers in caseof need. Anonymity revocation is done by a trusted third party. Cash systems that allow anonymity revocation arecalled fair.We present a coin system featuring both observer and fairness, showing that both concepts do not interfere witheach other and can be implemented simultaneously without loss of security. We prove this claim not only by presentinga fair variant of the Brands´ coin system but additionally by outlining a generic framework for fair wallets in whichessentially any blind signature scheme can be used. Unlike other fair off-line coin systems, fairness is implementedwith the help of the observer, thereby reducing the computational effort during the withdrawal 2006 artículo científico 0718-1876 https://www.redalyc.org/articulo.oa?id=96510102 en http://www.redalyc.org/revista.oa?id=965 Journal of Theoretical and Applied Electronic Commerce Research application/pdf Universidad de Talca Journal of Theoretical and Applied Electronic Commerce Research (Chile) Num.1 Vol.1