Electronic money (also identified as electronic cash, e-money, digital cash electronic currency, digital money, or digital currency) refers to money or scrip which is exchanged only by electronic means. Usually, this involves use of computer networks, the internet and digital stored value systems. Electronic Funds Transfer (EFT) and straight deposit are cases of E- Money. As well, it is a collective expression for financial cryptography and technologies allowing it.
Though electronic money has been an attractive problem for cryptography (see for illustration the work of David Chaum and Markus Jakobsson), to date, use of digital cash has been quite low-scale. One rare achievement has been Hong Kong's Octopus card system, which in progress as a transfer payment system and has full-grown into a extensively used electronic cash system. Singapore also has an electronic money execution for its public transportation system (commuter trains, bus, etc), which is extremely related to Hong Kong's Octopus card and based on the similar sort of card (FeliCa). There are as well one completion is in the Netherlands, recognized as Chipknip.