Digital Cash (also known as Electronic Money, e-money, electronic cash, electronic currency) is money which is exchanged on an electronic way. Digital cash is the equivalent of paper money in the virtual world. More or less all currencies can be used as digital cash. It is used to buy or sell services and goods via the internet. To transfer the money in the internet their are different electronic payment options. The most used option might be paypal.
A use-case for digital cash is a digital wallet
Froomkin, Michael A., Flood Control on the Information Ocean: Living With Anonymity, Digital Cash, and Distributed Databases,Published at 15 U. Pittsburgh Journal of Law and Commerce 395 1996
http://osaka.law.miami.edu/~froomkin/articles/oceanno.htm#xtocid583121
— Moritz Stigler 2011/08/12 22:13