WITHOUT doubt, one of the emerging developments that promises to change our on-line lives is digital cash. After all, as businesses increasingly eye the on-line world, and particularly the Internet as a potential outlet not just for promotion, but also for sales, distribution and services, the issues of secure and anonymous monetary transactions have become important. This is why several companies have not only begun to address secure transactions, but also anonymous transactions, like those now carried out with hard cash. After all, there are times when it is preferable to use cash, and many people dislike the openness of their financial status that electronic, credit-based transactions seem to present. The result is the concept of digital cash - and this has become the hot topic in magazines covering on-line affairs. This month's issue of Wired magazine calls digital cash 'the real killer app' emerging on-line - more so than video-on-demand and other much discussed technologies. An example of the development taking place is the work being done by a Dutch company, DigiCash. DigiCash has developed cryptographic protocols that promise to allow us to implement electronic cash transactions. There are many other companies and projects in the game - the NetCheque project is a debit-card system being tested in southern California, and the NetBill, being tested at Carnegie Mellon University, is a similar project. The application of digital cash is expected to influence industries beyond the on-line community. In the transportation industry many people believe digital money could potentially replace cash and ticket fares. The big players are also moving into the realm of digital money - banks and Microsoft. CitiBank is experimenting with prepaid cards, and Microsoft has bought out Intuit, which is known for its home financial management package, Quicken. The process envisioned by many debit card supporters is that it will be possible to download money into the card from home and then use it for purchases. The model also extends to cyberspace, where it is conceivable that people could download money from their banks into an on-line virtual wallet and then spend it on-line. This would allow easy personal exchanges of money, lending cash on the Net and would facilitate low-cost payments. The most important issue underlying digital money, whether on a smart card, smart wallet or in a computer-based virtual wallet, is about protocols. Protocols can either make a system an open window into people's personal lives, or promise them the privacy now provided by cash transactions. On top of this, useful protocols must prevent hackers from creating their own electronic digital printing presses that could put out forged electronic cash in volumes never envisioned by even the best counterfeiters of today. These issues are only the tip of the iceberg. It is still unclear who will regulate digital cash, and what will lend these collections of electronic pulses the credibility as accepted tender. Today, cash is backed by the banking system as well as the gold standard. Will the banks do the same with electronic cash? Also, implementing these protocols regionally, nationally or even globally will require infrastructure investments that must be underwritten. Can we expect the finance industry to do it, or should individuals be doing it with their taxes? Even though these questions remain unanswered, the digital and on-line communities are witnessing more ventures and experiments with possible solutions. As businesses are expected to jump into the on-line world next year, we can expect these issues to be resolved, and more quickly than some might think.