A study of electronic cash paradigm

The usage of electronic payment has been a daily occurrence to today society. Electronic cash (e-cash) is a new kind of electronic payment. Therefore, the definition and scheme of e-cash is still not definite. However, the usage of e-cash is already increasing in rapid rate. For example, Suica Card in Japan and London´s Oyster card. This paper review researches on e-cash from blind signature scheme to the famous BitCoin. From the review, we conclude that there are two kind of paradigm of e-cash, Centralized Paradigm and Decentralized Paradigm. The major difference between the two paradigms is their architecture of entity relationship. Centralized Paradigm has a single entity that oversees the system. Decentralized Paradigm is managed by community of users. We will show the properties of each paradigm and opportunity to improve each paradigm.