Finaly I have difficulty regarding Digicash as being all that socially responsible. Chaum's problems had a lot to do with the business terms he insisted on. What he had was a technology which allowed an improvement to a payment system. He imagined he had a monopoly on the only feasible solution. He was very baddly mistaken. The monopoly rents he demanded were more than the market was willing to pay for a working and deployed system - let alone for a patent license.
Where does the "monopoly rents" comment come from?
In other words, on what basis are you making that statement?
Chaum's reported demands for patent licensing fees were consistently above 10-20% of the service revenue plus a significant up front fee. Those levels are more usually associate with a monopolistic patent, hence 'monopoly rent'. The fact that Chaum didn't have the monopoly he appeared to imagine is probably why nobody was queuing up to pay his demands. Phill