SmartPT: PayTree with Smart Contracts

Abstract

There are several challenges in designing micropayment schemes for use in realworld applications such schemes need to be reliable, safe and efficient. A summary of various techniques by multiple researchers try to overcome these challenges is presented in this thesis. Current micropayment schemes don’t let users pay multiple merchants using a single chain or tree data structure but require a unique chain or tree for each merchant. This is problematic as a normal user interacts with multiple merchants during a single session and has to maintain a different chain or tree for each merchant, leading to increased storage space. In 1998, Jutla and Yung proposed a scheme called PayTree which supports paying multiple merchants using a single ee, their scheme needs an intermediary to verify the payment. In this thesis, we propose a system that allows a user to pay multiple merchants using a single tree without the need for any ntermediary. We do this by modifying PayTree to work without an intermediary by implementing it on the Ethereum blockchain. We provide proof of concept prototype that proves the feasibility of the system. We start by providing the necessary information for understanding micropayment schemes and how blockchain works. After this, we show how PayTree can be extended to work without an intermediary. Lastly, we conclude that this system enables users to reduce storage space while paying multiple merchants simultaneously.