During the last five years, the term mobile commerce (m-commerce) has appeared in the vocabulary of business people and researchers. Historically and conceptually, m-commerce can be regarded a new phase in electronic commerce (e-commerce). Although the term was introduced without a clear meaning and it is still lacking a single widely accepted definition, most people would say that the term m-commerce refers to e-commerce activities performed by people while on the move. Thus, m-commerce involves e-commerce transactions where a mobile terminal and a wireless network are used to conduct them. Therefore, m-commerce takes advantage of the e-commerce infrastructure developed for Internet e-commerce. Although in some cases an m-commerce transaction might be an alternative to a regular e-commerce transaction (such as buying a book) performed using a workstation and wired network, in many cases this is not the situation. The limitations of the mobile device - for instance, user interface limitations - are such that it is not attractive to perform typical Internet e-commerce transactions on them. Wireless technologies, combined with so-called ‘Internet-enabled’ terminals, constitute an ideal platform to realize new types of e-commerce transactions that are not possible or reasonable for wired terminals. The small and light, yet powerful, mobile terminals are almost always carried by their owners, just like wallets or watches. They can indeed also store electronic cash, credit card information, tickets, certificates of the Public Key Infrastructure (PKI), and so forth. Thus, they can assume the role of an e-wallet, as well as function as authentication and authorization devices in various contexts.