Digital Coins based on Hash Chain

We propose three digital coin schemes for doing electronic transactions over the Internet. These schemes are based on one-way hash functions. The rst scheme uses an ordinary one-way single hash function chain, which forms the basis of a simple micropayment scheme. The second scheme is based on a new technique called double-locked hash chain technique which overcomes some of the drawbacks found in single hash chain schemes. The third micropayment scheme presents a method to achieve client anonymity.