Contactless payment system with mobile NFC devices

Mobilne storitve predstavljajo enega od načinov zamenjave klasične plačilne kartice s pametnim telefonom in tehnologijo NFC (Near Field Communication). Pojavljajo se različne ideje kako izvesti gotovinske transakcije med dvema NFC napravama, brez vsakokratne povezave z zalednim sistemom, v katerem ima uporabnik svoj bančni račun. Cilj magistrskega dela je bil razviti sistem za demonstracijo in izvedbo brezkontaktnega plačevanja, ki temelji na uporabi elektronske gotovine. Njegova izvedba je razdeljena na strežniški del, ki predstavlja bančni sistem in uporabniški del, ki omogoča izmenjavo gotovine v nepovezanem načinu. Anonimno plačilo poteka med dvema mobilnima napravama Android s pomočjo komunikacije P2P (Peer-to-Peer) v tehnologiji NFC. Zasnovani in implementirani so postopki, ki omogočajo dvig in polog elektronske gotovine med mobilno aplikacijo in bančnim sistemom. Zagon aplikacije je omogočen z vpisom poznane kode in preverjanjem kartice NFC, varnost podatkov na napravi pa je zagotovljena s šifriranjem. Za detekcijo dvojne porabe je izveden postopek, ki omogoča beleženje podatkov o položeni elektronski gotovini.Mobile services represent one of the possibilities for replacing traditional payment cards with smartphones and NFC (Near Field Communication) technology. There are different ideas how to implement cash transactions between two NFC devices without respective connection with system of a user’s bank. The aim of the master’s thesis was to develop a system for demonstration and realization of contactless payment, based on electronic cash. The implementation of a system containing the server part which represents banking system, and the user application that enables the exchange of the electronic cash in offline mode. Anonymous payment is performed between two Android mobile devices via P2P (Peer-to-Peer) communication in NFC technology. The procedures for withdrawing and depositing of the electronic cash between the mobile application and the banking system are designed and implemented. It is possible to launch the application by entering the user’s PIN code and checking of the NFC card. Data security on a mobile device in ensured with the encryption. The procedure that enables the recording of a data about the deposited electronic cash is carried out and tested with the history data to detect double spending