Aspects of micropayments

There are many challenges to make micropayment systems on the Internet work as reliably, safely and efficiently as they need to. I have studied many of these problems, and seen how different researchers have tried to solve the challenges. A summary of many of these problems and suggested solutions are presented in this thesis. A new micropayments system is presented, based on Merkle's authentication tree and Wintemitz's one-time signatures. The scheme can add efficiency and flexibility to a range of existing micropayment schemes based on hash chains. Unlike earlier system, hash chains can be made relatively short, since the computational cost of authenticating a new hash chain is made small.