(Bob -- feel free to forward this to whatever list(s) you think might be interes ted -- Nick). I desribe an architecture providing usage control (as opposed to access control) for mutually suspicious objects (i.e., objects interacting across trust boundar ies), using bearer certificates: http://szabo.best.vwh.net/scarce.html Nick Szabo http://szabo.best.vwh.net/ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ --- end forwarded text -- ----------------- R. A. Hettinga The Internet Bearer Underwriting Corporation http://www.ibuc.com/ 44 Farquhar Street, Boston, MA 02131 USA "... however it may deserve respect for its usefulness and antiquity, [predicting the end of the world] has not been found agreeable to experience." -- Edward Gibbon, 'Decline and Fall of the Roman Empire'