Abstract
The Kontiki Working Group, formed in 1988, has 80 members drawn from transport authorities, transport operators, the industry, consultancies, research institutes and the banking sector. In addition to the smart card, the mobile phone is increasingly being used as a mobile user device. The interoperability of local applications based on a European standard is considered important for customers who desire seamless public transport wherever they wish to travel. Smartcard-based systems in Europe have proliferated and trails of mobile phone payment are underway. Technical considerations relating to these payment methods are considered, including security.