There's an article in EETimes 6 Nov 2000 p 160 about EDA providers who let you download tools, then pay for them by the hour. This differs from ASPs who run the apps on their machines (thereby exposing your secret designs). The interesting thing is that many tools run $5/hour, (e.g., for a $10K-$25K per seat app) and are billable in .01 second quanta. That's about a tenth of a penny. The license-server is filled with stored value (e.g., from a credit card, they'd probably take more anonymous transfers) and can run for a while without talking to the server. Interesting bizmodel and good example of crypto enabling commerce. [Though not really privacy ---you're still trusting the tool provider not to have hacked the tools to send your designs home..] "e*ECAD" is the company FWIW. No affiliation.