The notion of Mobile Payment Services (MPS) refers to making payments for goods, services and bills authorized, that are initiated and realized by using mobile devices independent from a bank website connection [4]. The transaction
can either be remote (SMS-based for instance) or processed locally via contactless technologies such as Near Field Communication (NFC) at the Point of Sale (P.O.S.) as Starbucks or REWE offer it in Germany. One aspect of MPS is mobile ticketing; it has been adopted by some public transport services and other public authorities in urban areas of larger Western and Eastern European cities, as at the airport or in train stations. The administration of the city of Düsseldorf for example offers cash-less payment options for parking tickets via mobile payment. It is a very convenient way to pay and even to extend the parking time via SMS payment. The city of Bucharest offers the possibility to pay the underground-ticket cash-less via mobile phone or via credit card that has to be held against an NFC terminal.