A new fair micropayment system based on hash chain

Micropayment systems in existence usually do not provide fairness, which means that either the customer or the merchant, or both, can cheat each other and gain a financial advantage by misbehaving in the protocols. We propose a new fair micropayment system based on hash chain, which is an offline, prepaid system and supports divisibility of digital coins in a simpler way. Moreover, in our system, a hash chain can be used to have transactions with different merchants. Compared with other micropayment schemes, e.g. Pay Word, no public-key operation is required, which improves the efficiency of our system. In addition, restricted anonymous is provided in our system.